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https://en.wikipedia.org/wiki/Scanline%20rendering | Scanline rendering (also scan line rendering and scan-line rendering) is an algorithm for visible surface determination, in 3D computer graphics, that works on a row-by-row basis rather than a polygon-by-polygon or pixel-by-pixel basis. All of the polygons to be rendered are first sorted by the top y coordinate at which they first appear, then each row or scan line of the image is computed using the intersection of a scanline with the polygons on the front of the sorted list, while the sorted list is updated to discard no-longer-visible polygons as the active scan line is advanced down the picture.
The main advantage of this method is that sorting vertices along the normal of the scanning plane reduces the number of comparisons between edges. Another advantage is that it is not necessary to translate the coordinates of all vertices from the main memory into the working memory—only vertices defining edges that intersect the current scan line need to be in active memory, and each vertex is read in only once. The main memory is often very slow compared to the link between the central processing unit and cache memory, and thus avoiding re-accessing vertices in main memory can provide a substantial speedup.
This kind of algorithm can be easily integrated with many other graphics techniques, such as the Phong reflection model or the Z-buffer algorithm.
Algorithm
The usual method starts with edges of projected polygons inserted into buckets, one per scanline; the rasterizer maintains an active edge table (AET). Entries maintain sort links, X coordinates, gradients, and references to the polygons they bound. To rasterize the next scanline, the edges no longer relevant are removed; new edges from the current scanlines' Y-bucket are added, inserted sorted by X coordinate. The active edge table entries have X and other parameter information incremented. Active edge table entries are maintained in an X-sorted list, effecting a change when 2 edges cross. After updating edges, the active edge table is traversed in X order to emit only the visible spans, maintaining a Z-sorted active Span table, inserting and deleting the surfaces when edges are crossed.
Variants
A hybrid between this and Z-buffering does away with the active edge table sorting, and instead rasterizes one scanline at a time into a Z-buffer, maintaining active polygon spans from one scanline to the next.
In another variant, an ID buffer is rasterized in an intermediate step, allowing deferred shading of the resulting visible pixels.
History
The first publication of the scanline rendering technique was probably by Wylie, Romney, Evans, and Erdahl in 1967.
Other early developments of the scanline rendering method were by Bouknight in 1969, and Newell, Newell, and Sancha in 1972. Much of the early work on these methods was done in Ivan Sutherland's graphics group at the University of Utah, and at the Evans & Sutherland company in Salt Lake City.
Use in realtime rendering
The early Ev |
https://en.wikipedia.org/wiki/Mac%20OS%20X%20Server | Mac OS X Server is a discontinued series of Unix-like server operating systems developed by Apple Inc. based on macOS. It provided server functionality and system administration tools, and tools to manage both macOS-based computers and iOS-based devices, network services such as a mail transfer agent, AFP and SMB servers, an LDAP server, and a domain name server, as well as server applications including a Web server, database, and calendar server.
Starting with OS X Lion, Apple stopped selling a standalone server operating system, instead releasing an add-on Server app marketed as OS X Server (and later macOS Server), which was sold through the Mac App Store. The Server app lacked many features from Mac OS X Server, and later versions of the app only included functionality related to user and group management, Xsan, and mobile device management through profiles. The Server app was discontinued on April 21, 2022, and Apple said that later versions of macOS would drop support for it.
History
Mac OS X Server is based on an open source foundation called Darwin and uses open industry standards and protocols. Mac OS X Server was provided as the operating system for Xserve computers, rack-mounted server computers designed by Apple. Also, it was optionally pre-installed on the Mac Mini and Mac Pro and was sold separately for use on any Macintosh computer meeting its minimum requirements.
Mac OS X Server 1.0 (Rhapsody)
Mac OS X Server 1.0 was released in March 1999, predating the release of the consumer version of Mac OS X by two years. Mac OS X Server 1.0 was based on Rhapsody, a hybrid of OPENSTEP from NeXT Computer and Mac OS 8.5.1. The GUI looked like a mixture of Mac OS 8's Platinum appearance with OPENSTEP's NeXT-based interface. It included a runtime layer called Blue Box for running legacy Mac OS-based applications within a separate window. There was discussion of implementing a 'transparent blue box' which would intermix Mac OS applications with those written for Rhapsody's Yellow Box environment, but this would not happen until Mac OS X's Classic environment. Apple File Services, Macintosh Manager, QuickTime Streaming Server, WebObjects, and NetBoot were included with Mac OS X Server 1.0. It could not use FireWire devices. The last release is Mac OS X Server 1.2v3.
Mac OS X Server 10.0 (Cheetah)
Mac OS X Server 10.0 (released May 21, 2001) included the new Aqua user interface, Apache, PHP, MySQL, Tomcat, WebDAV support, Macintosh Manager, and NetBoot.
Mac OS X Server 10.1 (Puma)
Mac OS X Server 10.1 (released September 25, 2001) featured improved performance, increased system stability, and decreased file transfer times compared to Mac OS X Server 10.0. Support was added for RAID 0 and RAID 1 storage configurations, and Mac OS 9.2.1 in NetBoot.
Mac OS X Server 10.2 (Jaguar)
Mac OS X Server 10.2 (released August 23, 2002) includes updated Open Directory user and file management, which with this release is based on LDAP, beginning the depr |
https://en.wikipedia.org/wiki/AIBO | AIBO (stylized as aibo, abbreviated as Artificial Intelligence RoBOt, homonymous with , "pal" or "partner" in Japanese) is a series of robotic dogs designed and manufactured by Sony. Sony announced a prototype Aibo in mid-1998, and the first consumer model was introduced on 11 May 1999. New models were released every year until 2006. Although most models were dogs, other inspirations included lion cubs, huskies, Jack Russell terriers, bull terrier, and space explorers. Only the ERS-7, ERS-110/111 and ERS-1000 versions were explicitly a "robotic dog", but the 210 can also be considered a dog due to its Jack Russell Terrier appearance and face.
In 2006, AIBO was added into the Carnegie Mellon University Robot Hall of Fame.
On 26 January 2006 Sony announced that it would discontinue AIBO and several other products in an effort to make the company more profitable. Sony's AIBO customer support was withdrawn gradually, with support for the final ERS-7M3 ending in March 2013.
In July 2014, Sony stopped providing repairs for AIBO products and did not provide customer support or repair for the older AIBO robots.
In November 2017, Sony announced a new generation of AIBO. The fourth generation model, ERS-1000, was launched in Japan on 11 January 2018. The second lottery sale was set on 6 February 2018.
History
The AIBO product line was developed at Sony's Computer Science Laboratory (CSL). Founded in 1990, CSL was set up to emulate the innovation center at Xerox's Palo Alto Research Center (PARC). CSL's first product was the Aperios operating system, which later formed the base software used by some AIBO models. When Nobuyuki Idei became president of Sony in 1995, he sought to adopt a digital agenda and gave greater prominence to CSL.
Dr. Toshitada Doi is credited as AIBO's original progenitor: in 1994 he had started work on robots at CSL with artificial intelligence expert Masahiro Fujita. Fujita felt that the robot's behaviors needed to "be sufficiently complex or unexpected so that people keep an interest in watching or taking care of it". Fujita argued at the time that, while technologies such as voice recognition and vision were not mature enough for critical applications, their limited capabilities could be a novel, interesting and attractive feature for "appropriately designed entertainment robots". His early monkey-like prototype "MUTANT" included behaviors such as tracking a yellow ball, shaking hands, karate strikes and sleeping, which were later adopted in AIBOs. Fujita received the IEEE Inaba Technical Award for Innovation Leading to Production for AIBO as "the world's first mass-market consumer robot for entertainment applications".
Artist Hajime Sorayama was enlisted to create the initial designs for the AIBO's body. Those designs are now part of the permanent collections of the Museum of Modern Art and the Smithsonian Institution. The first generation AIBO design won Japan's prestigious Good Design Award, Grand Prize and a special Inte |
https://en.wikipedia.org/wiki/IP%20over%20Avian%20Carriers | In computer networking, IP over Avian Carriers (IPoAC) is a joke proposal to carry Internet Protocol (IP) traffic by birds such as homing pigeons. IP over Avian Carriers was initially described in issued by the Internet Engineering Task Force, written by D. Waitzman, and released on April 1, 1990. It is one of several April Fools' Day Request for Comments.
Waitzman described an improvement of his protocol in , IP over Avian Carriers with Quality of Service (1 April 1999). Later, in —released on 1 April 2011, and 13 years after the introduction of IPv6—Brian Carpenter and Robert Hinden published Adaptation of RFC 1149 for IPv6.
IPoAC has been successfully implemented, but for only nine packets of data, with a packet loss ratio of 55% (due to operator error), and a response time ranging from to over . Thus, this technology suffers from high latency.
Real-life implementation
On 28 April 2001, IPoAC was implemented by the Bergen Linux user group, under the name CPIP (for Carrier Pigeon Internet Protocol). They sent nine packets over a distance of approximately , each carried by an individual pigeon and containing one ping (ICMP echo request), and received four responses.
Script started on Sat Apr 28 11:24:09 2001
$ /sbin/ifconfig tun0
tun0 Link encap:Point-to-Point Protocol
inet addr:10.0.3.2 P-t-P:10.0.3.1 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:150 Metric:1
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
collisions:0
RX bytes:88 (88.0 b) TX bytes:168 (168.0 b)
$ ping -c 9 -i 900 10.0.3.1
PING 10.0.3.1 (10.0.3.1): 56 data bytes
64 bytes from 10.0.3.1: icmp_seq=0 ttl=255 time=6165731.1 ms
64 bytes from 10.0.3.1: icmp_seq=4 ttl=255 time=3211900.8 ms
64 bytes from 10.0.3.1: icmp_seq=2 ttl=255 time=5124922.8 ms
64 bytes from 10.0.3.1: icmp_seq=1 ttl=255 time=6388671.9 ms
--- 10.0.3.1 ping statistics ---
9 packets transmitted, 4 packets received, 55% packet loss
round-trip min/avg/max = 3211900.8/5222806.6/6388671.9 ms
Script done on Sat Apr 28 14:14:28 2001
This real life implementation was mentioned by the French member of parliament Martine Billard in the French National Assembly, during debates about HADOPI.
The implementation was noted in the song "Paper Pings" by Steve Savitzky.
Risks
In December 2005, a Gartner report on bird flu that concluded "A pandemic wouldn't affect IT systems directly" was humorously criticized for neglecting to consider RFC 1149 and RFC 2549 in its analysis.
Known risks to the protocol include:
Carriers being attacked by birds of prey. RFC2549: "Unintentional encapsulation in hawks has been known to occur, with decapsulation being messy and the packets mangled."
Carriers being blown off course. RFC1149: "While broadcasting is not specified, storms can cause data loss."
The absence of viable local carriers. RFC6214: "In some locations, such as New Zealand, |
https://en.wikipedia.org/wiki/Route%20flapping | In computer networking and telecommunications, route flapping occurs when a router alternately advertises a destination network via one route then another, or as unavailable and then available again, in quick sequence.
Route flapping is caused by pathological conditions (hardware errors, software errors, configuration errors, intermittent errors in communications links, unreliable connections, etc.) within the network which cause certain reachability information to be repeatedly advertised and withdrawn. For example, link flap occurs when an interface on a router has a hardware failure that causes the router to announce it alternately as "up" and "down".
In networks with link-state routing protocols, route flapping will force frequent recalculation of the topology by all participating routers. In networks with distance-vector routing protocols, route flapping can trigger routing updates with every state change. In both cases, it prevents the network from converging.
Route flapping can be contained to a smaller area of the network if route aggregation is used. As an aggregate route will not be withdrawn as long as at least one of the aggregated subnets is still valid, a flapping route that is part of an aggregate will not disturb the routers that receive the aggregate.
See also
BGP route damping
Supernet
References
Flapping |
https://en.wikipedia.org/wiki/UNICOS | UNICOS is a range of Unix and after it Linux operating system (OS) variants developed by Cray for its supercomputers. UNICOS is the successor of the Cray Operating System (COS). It provides network clustering and source code compatibility layers for some other Unixes. UNICOS was originally introduced in 1985 with the Cray-2 system and later ported to other Cray models. The original UNICOS was based on UNIX System V Release 2, and had many Berkeley Software Distribution (BSD) features (e.g., computer networking and file system enhancements) added to it.
Development
CX-OS was the original name given to what is now UNICOS. This was a prototype system which ran on a Cray X-MP in 1984 before the Cray-2 port. It was used to demonstrate the feasibility of using Unix on a supercomputer system, before Cray-2 hardware was available.
The operating system revamp was part of a larger movement inside Cray Research to modernize their corporate software: including rewriting their most important Fortran compiler (cft to cft77) in a higher-level language (Pascal) with more modern optimizations and vectorizations.
As a migration path for existing COS customers wishing to transition to UNICOS, a Guest Operating System (GOS) capability was introduced into COS. The only guest OS that was ever supported was UNICOS. A COS batch job would be submitted to start up UNICOS, which would then run as a subsystem under COS, using a subset of the systems CPUs, memory, and peripheral devices. The UNICOS that ran under GOS was exactly the same as when it ran stand-alone: the difference was that the kernel would make certain low-level hardware requests through the COS GOS hook, rather than directly to the hardware.
One of the sites that ran very early versions of UNICOS was Bell Labs, where Unix pioneers including Dennis Ritchie ported parts of their Eighth Edition Unix (including STREAMS input/output (I/O)) to UNICOS. They also experimented with a guest facility within UNICOS, allowing the stand-alone version of the OS to host itself.
Releases
Cray released several different OSs under the name UNICOS, including:
UNICOS: the original Cray Unix, based on System V. Used on the Cray-1, Cray-2, X-MP, Y-MP, C90, etc.
UNICOS MAX: a Mach-based microkernel used on the T3D's processing elements, together with UNICOS on the host Y-MP or C90 system.
UNICOS/mk: a serverized version of UNICOS using the Chorus microkernel to make a distributed operating system. Used on the T3E. This was the last Cray OS really based on UNICOS sources, as the following products were based on different sources and simply used the "UNICOS" name.
UNICOS/mp: not derived from UNICOS, but based on IRIX 6.5. Used on the X1.
UNICOS/lc: not derived from UNICOS, but based on SUSE Linux. Used on the XT3, XT4 and XT5. UNICOS/lc 1.x comprises a combination of
the compute elements run the Catamount microkernel (which itself is based on Cougaar)
the service elements run SUSE Linux
Cray Linux Environment (CLE): from releas |
https://en.wikipedia.org/wiki/FastTrack | FastTrack is a peer-to-peer (P2P) protocol that was used by the Kazaa, Grokster, iMesh and Morpheus file sharing programs. FastTrack was the most popular file sharing network in 2003, and used mainly for the exchange of music mp3 files. The network had approximately 2.4 million concurrent users in 2003. It is estimated that the total number of users was greater than that of Napster at its peak.
History
The FastTrack protocol and Kazaa were created and developed by Estonian programmers of BlueMoon Interactive headed by Jaan Tallinn, the same team that later created Skype. After selling it to Niklas Zennström from Sweden and Janus Friis from Denmark, it was introduced in March 2001 by their Dutch company Consumer Empowerment. It appeared during the end of the first generation of P2P networks – Napster shut down in July of that year. There are three FastTrack-based networks, and they use mutually incompatible versions of the protocol. The most popular clients on each are Kazaa (and its variations), Grokster, and iMesh. For more information about the various lawsuits surrounding Kazaa and Sharman Networks, see Kazaa.
Technology
FastTrack uses supernodes to improve scalability.
To allow downloading from multiple sources, FastTrack employs the UUHash hashing algorithm. While UUHash allows very large files to be checksummed in a short time, even on slow weak computers, it also allows for massive corruption of a file to go unnoticed. Many people, as well as the RIAA, have exploited this vulnerability to spread corrupt and fake files on the network.
The FastTrack protocol uses encryption and was not documented by its creators. The first clients were all closed source software. However, initialization data for the encryption algorithms is sent in the clear and no public key encryption is used, so reverse engineering was made comparatively easy. In 2003, open source programmers succeeded in reverse-engineering the portion of the protocol dealing with client-supernode communication, but the supernode-supernode communication protocol remains largely unknown.
Clients
The following programs are or have been FastTrack clients:
Kazaa and variants
KCeasy (requires the gIFT-fasttrack plugin)
Grokster
iMesh
Morpheus, until 2002
Apollon - KDE-Based
giFT-FastTrack – a giFT plugin
MLDonkey, a free multi-platform multi-network file sharing client
See also
Kad network
Overnet
Open Music Model
Comparison of file sharing applications
References
External links
giFT-FastTrack home page
Documentation of the known parts of the FastTrack protocol, from giFT-FastTrack
Boardwatch [ Interview with Niklas Zennstrom], July 17, 2003
FTWall - A firewalling technique for blocking the fast-track protocol.
Advanced Peer-Based Technology Business Models. Ghosemajumder, Shuman. MIT Sloan School of Management, 2002.
Music Downloads: Pirates- or Customers? . Silverthorne, Sean. Harvard Business School Working Knowledge, 2004.
File sharing networks
File transfer p |
https://en.wikipedia.org/wiki/Closure | Closure may refer to:
Conceptual
Psychology
Closure (psychology), the state of experiencing an emotional conclusion to a difficult life event
Computer science
Closure (computer programming), an abstraction binding a function to its scope
Relational database model: Set-theoretic formulation and Armstrong's axioms for its use in database theory
Mathematics
Closure (mathematics), the result of applying a closure operator
Closure (topology), for a set, the smallest closed set containing that set
Philosophy
Epistemic closure, a principle in epistemology
Deductive closure, a principle in logic
Cognitive closure, a principle in philosophy of mind
Closure: A Short History of Everything, a philosophical book by Hilary Lawson
Sociology
Closure (sociology)
Closure, a concept in the social construction of technology
Physical objects
Closure (container) used to seal a bottle, jug, jar, can, or other container
Closure (wine bottle), a stopper
Hook-and-eye closure
Arts and entertainment
Film and television
Straightheads, a 2007 British thriller film, US release title Closure
"Closure" (The X-Files), a 2000 episode of the television series The X-Files
"Closure" (8 Simple Rules episode), a 2005 episode of the sitcom 8 Simple Rules
"Closure" (Raines), a 2007 episode of the crime drama Raines
"Closure" (Tru Calling), a 2004 episode of the supernatural drama Tru Calling
A two-part episode, split between seasons 1 and 2 of Law and Order: SVU
"Closure" (Agents of S.H.I.E.L.D.), a 2015 episode of the television series Agents of S.H.I.E.L.D.
Music
Closure (band), Canadian rock band
Closure (video), a 1997 Nine Inch Nails video set
Albums and EPs
Closure (Attila album), 2021 album by Attila
Closure (Closure album), 2003 album by Closure
Closure, 2004 EP by Everclear
Closure (Integrity album), 2001 album by Integrity
Closure (Spahn Ranch album), 2001
Closure: Live, 2001 live album by Theatre of Tragedy
Songs
"Closure", by Aly & AJ from Insomniatic, 2007
"Closure", by Asking Alexandria from Reckless & Relentless, 2011
"Closure", by Botch from The Unifying Themes of Sex, Death and Religion, 1997
"Closure" (Cadet song), single by Cadet, 2017
"Closure" (Chevelle song), by Chevelle from Wonder What's Next, 2002
"Closure", by Chris Brown featuring H.E.R. from Breezy, 2022
"Closure", by Divine Heresy from Bleed the Fifth, 2007
"Closure", by Gabrielle from Always, 2007
"Closure", single by Hayley Warner, 2015
"Closure", by Hood from Outside Closer, 2005
"Closure", by Maroon 5 from Red Pill Blues, 2017
"Closure", by Opeth from Damnation, 2003
"Closure" (Scarlett Belle song), single by Scarlett Belle, 2010
"Closure", by The Story So Far from Under Soil and Dirt, 2011
"Closure", by Taylor Swift from Evermore, 2020
"Closure", by Jack & Jack, 2018
"Closure", by I Prevail from "True Power", 2022
Other arts and entertainment
Closure (video game), a 2012 puzzle game
Closure: A Short History of Everything, a philosophical book b |
https://en.wikipedia.org/wiki/Configuration | Configuration or configurations may refer to:
Computing
Computer configuration or system configuration
Configuration file, a software file used to configure the initial settings for a computer program
Configurator, also known as choice board, design system, or co-design platform, used in product design to capture customers' specifications
Configure script ("./configure" in Unix), the output of Autotools; used to detect system configuration
CONFIG.SYS, the primary configuration file for DOS and OS/2 operating systems
Mathematics
Configuration (geometry), a finite set of points and lines with certain properties
Configuration (polytope), special kind of configuration for regular polytopes
Configuration space (mathematics), a space representing assignments of points to non-overlapping positions on a topological space
Physics
Configuration space (physics), in classical mechanics, the vector space formed by the parameters of a system
Electron configuration, the distribution of electrons of an atom or molecule
Molecular configuration, the permanent geometry that results from the spatial arrangement of molecular bonds
Configuron, a quasiparticle
History
Historical configuration of the province of Granada
Other uses
Configuration (locomotive parts), denoting the number of leading, driving, and trailing axles on a locomotive
Configuration management, a systems engineering quality control process
Configurational analysis, a method of studying human behaviour.
Configurations (journal), an academic journal established in 1993 by the Society for Literature, Science, and the Arts
See also |
https://en.wikipedia.org/wiki/Data%20%28Star%20Trek%29 | Data is a fictional character in the Star Trek franchise. He appears in the television series Star Trek: The Next Generation (TNG) and the first and third seasons of Star Trek: Picard; and the feature films Star Trek Generations (1994), First Contact (1996), Insurrection (1998), and Nemesis (2002). Data is portrayed by actor Brent Spiner.
Data was found by Starfleet in 2338. He was the sole survivor on Omicron Theta in the rubble of a colony left after an attack from the Crystalline Entity. He is a synthetic life form with artificial intelligence, designed and built by Doctor Noonien Soong in his own likeness (likewise portrayed by Spiner). Data is a self-aware, sapient, sentient and anatomically fully functional male android who serves as the second officer and chief operations officer aboard the Federation starship USS Enterprise-D and later the USS Enterprise-E.
His positronic brain allows him impressive computational capabilities. He experienced ongoing difficulties during the early years of his life with understanding various aspects of human behavior and was unable to feel emotion or understand certain human idiosyncrasies, inspiring him to strive for his own humanity. This goal eventually led to the addition of an "emotion chip", created by Soong, to Data's positronic net. Although Data's endeavor to increase his humanity and desire for human emotional experience is a significant plot point (and source of humor) throughout the series, he consistently shows a nuanced sense of wisdom, sensitivity and curiosity, garnering respect from his peers and colleagues.
Data is in many ways a successor to the original Star Treks Spock (Leonard Nimoy), in that the character has superior mental skills and offers an "outsider's" perspective on humanity.
Development
Gene Roddenberry told Brent Spiner that over the course of the series, Data was to become "more and more like a human until the end of the show, when he would be very close, but still not quite there. That was the idea and that's the way that the writers took it." Spiner felt that Data exhibited the Chaplinesque characteristics of a sad, tragic clown. To get into his role as Data, Spiner used the character of Robby the Robot from the film Forbidden Planet as a role model.
Commenting on Data's perpetual albino-like appearance, he said: "I spent more hours of the day in make-up than out of make-up", so much so that he even called it a way of method acting. Spiner also portrayed Data's manipulative and malevolent brother Lore (a role he found much easier to play, because the character was "more like me"), and Data's creator, Dr. Noonien Soong. Additionally, he portrayed another Soong-type android, B-4, in the film Star Trek: Nemesis, and also Arik Soong, one of Soong's ancestors in three episodes of Star Trek: Enterprise. Spiner said his favorite Data scene takes place in "Descent", when Data plays poker on the holodeck with a re-creation of the famous physicist Stephen Hawking, played by Haw |
https://en.wikipedia.org/wiki/Backyard%20Blitz | Backyard Blitz was a Logie Award winning Australian lifestyle and DIY television program that aired on the Nine Network between 2000 through to 2007 before its cancellation. It was hosted by Jamie Durie and was created by Don Burke and produced by his CTC Productions team.
Overview
The show featured a very similar premise to the show Ground Force, in which a team of gardeners employed by the show descend on a supposedly worthy individual's place and improve the garden for the cameras within a specified time limit. This similarity led to legal action being taken by the rival Seven Network, which at the time was set to debut an Australian version of Ground Force. Seven ultimately lost its claim as Don Burke's CTC was able to argue that Burke's previous program Burke's Backyard had featured backyard garden renovations which they claimed naturally morphed into the Backyard Blitz concept.
The four regular presenters on the show were landscaper Jamie Durie (the main host and the show's lead landscaper), Scott Cam (builder/carpenter), Nigel Ruck (landscaper) and Jody Rigby (horticulturist). The show would launch the television careers of Durie, Rigby and Cam; Durie and Cam would later become hosts of Nine's successful reality television show The Block during different seasons.
During its run the show was immensely popular across all demographics; it regularly won its time slot and consistently ranked in the top 20 national shows at year's end. However, on 14 November 2006 Backyard Blitz was axed by the Nine Network after seven years on air. Don Burke, whose own show Burke's Backyard was broadcast by Nine for nearly 18 years before it was axed in 2004, said his production company was "quite shocked by this decision". In mid-2007 Nine aired the six remaining unaired episodes that were filmed before the show was cancelled.
In 2008, Nine started airing a spin-off show called Domestic Blitz, hosted by Cam and Shelley Craft. The show lasted until 2010, encompassing 4 seasons.
Awards
During the show's run, Backyard Blitz has won (and been nominated) for several Logie Awards. The show won six consecutive 'Most Popular Lifestyle Program' awards (2002–2006), and was nominated in the same category in 2007 but lost. Jamie Durie won the 'Most Popular New Male Talent' in 2001 and was nominated for 'Most Popular TV Presenter' in 2005 and 2006 for his role on the show.
See also
Domestic Blitz
Ground Force
Mucking In
List of Australian television series
References
External links
Australian non-fiction television series
Nine Network original programming
2000 Australian television series debuts
2007 Australian television series endings
Gardening television |
https://en.wikipedia.org/wiki/CDR%20coding | In computer science CDR coding is a compressed data representation for Lisp linked lists. It was developed and patented by the MIT Artificial Intelligence Laboratory, and implemented in computer hardware in a number of Lisp machines derived from the MIT CADR.
CDR coding is in fact a fairly general idea; whenever a data object A ends in a reference to another data structure B, we can instead place the structure B itself there, overlapping and running off the end of A. By doing this we free the space required by the reference, which can add up if done many times, and also improve locality of reference, enhancing performance on modern machines. The transformation is especially effective for the cons-based lists it was created for; we free about half of the space for each node we perform this transformation on.
It is not always possible to perform this substitution, because there might not be a large enough chunk of free space beyond the end of A. Thus, some objects will end in a real reference, and some with the referenced object, and the machine must be able to tell by reading the final cell which one it is. This can be accomplished with some inefficiency in software by the use of tagged pointers, which allow a pointer in a final position to be specifically tagged as such, but is best done in hardware.
In the presence of mutable objects, CDR coding becomes more complex. If a reference is updated to point to another object, but currently has an object stored in that field, the object must be relocated, along with any other pointers to it. Not only are such moves typically expensive or impossible, but over time they cause fragmentation of the store. This problem is typically avoided by using CDR coding only on immutable data structures.
External links
Lisp (programming language)
Data compression |
https://en.wikipedia.org/wiki/Threaded%20code | In computer science, threaded code is a programming technique where the code has a form that essentially consists entirely of calls to subroutines. It is often used in compilers, which may generate code in that form or be implemented in that form themselves. The code may be processed by an interpreter or it may simply be a sequence of machine code call instructions.
Threaded code has better density than code generated by alternative generation techniques and by alternative calling conventions. In cached architectures, it may execute slightly slower. However, a program that is small enough to fit in a computer processor's cache may run faster than a larger program that suffers many cache misses. Small programs may also be faster at thread switching, when other programs have filled the cache.
Threaded code is best known for its use in many compilers of programming languages, such as Forth, many implementations of BASIC, some implementations of COBOL, early versions of B, and other languages for small minicomputers and for amateur radio satellites.
History
The common way to make computer programs is to use a compiler to translate source code (written in some symbolic language) to machine code. The resulting executable is typically fast but, because it is specific to a hardware platform, it isn't portable. A different approach is to generate instructions for a virtual machine and to use an interpreter on each hardware platform. The interpreter instantiates the virtual machine environment and executes the instructions. Thus, only the interpreter must be compiled.
Early computers had relatively little memory. For example, most Data General Nova, IBM 1130, and many of the first microcomputers had only 4 kB of RAM installed. Consequently, a lot of time was spent trying to find ways to reduce a program's size, to fit in the available memory.
One solution is to use an interpreter which reads the symbolic language a bit at a time, and calls functions to perform the actions. As the source code is typically much denser than the resulting machine code, this can reduce overall memory use. This was the reason Microsoft BASIC is an interpreter: its own code had to share the 4 kB memory of machines like the Altair 8800 with the user's source code. A compiler translates from a source language to machine code, so the compiler, source, and output must all be in memory at the same time. In an interpreter, there is no output.
Threaded code is a formatting style for compiled code that minimizes memory use. Instead of writing out every step of an operation at its every occurrence in the program, as was common in macro assemblers for instance, the compiler writes each common bit of code into a subroutine. Thus, each bit exists in only one place in memory (see "Don't repeat yourself"). The top-level application in these programs may consist of nothing but subroutine calls. Many of these subroutines, in turn, also consist of nothing but lower-level subroutine ca |
https://en.wikipedia.org/wiki/TTL | TTL may refer to:
Photography
Through-the-lens metering, a camera feature
Zenit TTL, an SLR film camera named for its TTL metering capability
Technology
Time to live, a computer data lifespan-limiting mechanism
Transistor–transistor logic, a family of integrated-circuit digital logic
Differential TTL, a serial signaling standard based on TTL
Turtle (syntax), a computer data format used in semantic web technologies
Other uses
Taiwan Tobacco and Liquor, a state-owned manufacturer
"TTL (Time to Love)", a single by South Korean girl group T-ara and boy band Supernova |
https://en.wikipedia.org/wiki/Instruction%20set%20architecture | In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an implementation.
In general, an ISA defines the supported instructions, data types, registers, the hardware support for managing main memory, fundamental features (such as the memory consistency, addressing modes, virtual memory), and the input/output model of a family of implementations of the ISA.
An ISA specifies the behavior of machine code running on implementations of that ISA in a fashion that does not depend on the characteristics of that implementation, providing binary compatibility between implementations. This enables multiple implementations of an ISA that differ in characteristics such as performance, physical size, and monetary cost (among other things), but that are capable of running the same machine code, so that a lower-performance, lower-cost machine can be replaced with a higher-cost, higher-performance machine without having to replace software. It also enables the evolution of the microarchitectures of the implementations of that ISA, so that a newer, higher-performance implementation of an ISA can run software that runs on previous generations of implementations.
If an operating system maintains a standard and compatible application binary interface (ABI) for a particular ISA, machine code will run on future implementations of that ISA and operating system. However, if an ISA supports running multiple operating systems, it does not guarantee that machine code for one operating system will run on another operating system, unless the first operating system supports running machine code built for the other operating system.
An ISA can be extended by adding instructions or other capabilities, or adding support for larger addresses and data values; an implementation of the extended ISA will still be able to execute machine code for versions of the ISA without those extensions. Machine code using those extensions will only run on implementations that support those extensions.
The binary compatibility that they provide makes ISAs one of the most fundamental abstractions in computing.
Overview
An instruction set architecture is distinguished from a microarchitecture, which is the set of processor design techniques used, in a particular processor, to implement the instruction set. Processors with different microarchitectures can share a common instruction set. For example, the Intel Pentium and the AMD Athlon implement nearly identical versions of the x86 instruction set, but they have radically different internal designs.
The concept of an architecture, distinct from the design of a specific machine, was developed by Fred Brooks at IBM during the design phase of System/360.
Some virtual machines that support bytecode as their ISA such as Smalltalk, the Java virtual machine, and |
https://en.wikipedia.org/wiki/Maclisp | Maclisp (or MACLISP, sometimes styled MacLisp or MacLISP) is a programming language, a dialect of the language Lisp. It originated at the Massachusetts Institute of Technology's (MIT) Project MAC (from which it derived its prefix) in the late 1960s and was based on Lisp 1.5. Richard Greenblatt was the main developer of the original codebase for the PDP-6; Jon L. White was responsible for its later maintenance and development. The name Maclisp began being used in the early 1970s to distinguish it from other forks of PDP-6 Lisp, notably BBN Lisp.
History
Maclisp is a descendant of Lisp 1.5. Maclisp departs from Lisp 1.5 by using a value cell to access and store the dynamic values of variables; Lisp 1.5 used a linear search of an association list to determine a variable's value. The Maclisp variable evaluation is faster but has different variable semantics. Maclisp also employed reader macros to make more readable input and output, termed input/output (I/O). Instead of entering (QUOTE A), one could enter 'A to get the same s-expression. Although both implementations put functions on the property list, Maclisp uses different syntax to define functions. Maclisp also has a load-on-demand feature.
Maclisp began on Digital Equipment Corporation PDP-6 and PDP-10 computers running the Incompatible Timesharing System (ITS); later it was ported to all other PDP-10 operating systems, for example, Timesharing / Total Operating System, TOPS-10 and TOPS-20. The original implementation was in assembly language, but a later implementation on Multics used PL/I. Maclisp developed considerably in its lifetime. Major features were added which in other language systems would typically correspond to major release numbers.
Maclisp was used to implement the Macsyma computer algebra system (CAS) or symbolic algebra program. Macsyma's development also drove several features in Maclisp. The SHRDLU blocks-world program was written in Maclisp, and so the language was in widespread use in the artificial intelligence (AI) research community through the early 1980s. It was also used to implement other programming languages, such as Planner and Scheme. Multics Maclisp was used to implement the first Lisp-based Emacs.
Maclisp was an influential Lisp implementation, but is no longer maintained actively. It now runs on PDP-10 emulators and can be used for experimenting with early AI programs.
Characteristics
Maclisp began with a small, fixed number of data types: cons cell, atom (later termed symbol), integer, and floating-point number. Later additions included: arrays, which were never first-class data types; arbitrary-precision integers (bignums); strings; and tuples. All objects (except inums) were implemented as pointers, and their data type was determined by the block of memory into which it pointed, with a special case for small numbers (inums).
Programs could be interpreted or compiled. Compiled behavior was the same as interpreted except that local variabl |
https://en.wikipedia.org/wiki/Lisp%20Machine%20Lisp | Lisp Machine Lisp is a programming language, a dialect of the language Lisp. A direct descendant of Maclisp, it was initially developed in the mid to late 1970s as the system programming language for the Massachusetts Institute of Technology (MIT) Lisp machines. Lisp Machine Lisp was also the Lisp dialect with the most influence on the design of Common Lisp.
Lisp Machine Lisp branched into three dialects. Symbolics named their variant ZetaLisp. Lisp Machines, Inc. and later Texas Instruments (with the TI Explorer) would share a common code base, but their dialect of Lisp Machine Lisp would differ from the version maintained at the MIT AI Lab by Richard Stallman and others.
Manual
The Lisp Machine Manual describes the Lisp Machine Lisp language in detail. The manual was popularly termed the Chine Nual, because the full title was printed across the front and back covers such that only those letters appeared on the front. This name is sometimes further abbreviated by blending the two words into Chinual.
Traits
Lisp Machine Lisp features include:
Support for object-oriented programming via an object system named Flavors
Uses dynamic binding, but supports closures with a special construct
Integer numbers were read and printed in octal (base 8) by default
Dividing floating point numbers returned decimals, dividing integers returned rational numbers (fractions)
References
Lisp programming language family
Lisp (programming language)
1970s software
Programming languages created in 1976 |
https://en.wikipedia.org/wiki/Data%20stream | In connection-oriented communication, a data stream is the transmission of a sequence of digitally encoded signals to convey information. Typically, the transmitted symbols are grouped into a series of packets.
Data streaming has become ubiquitous. Anything transmitted over the Internet is transmitted as a data stream. Using a mobile phone to have a conversation transmits the sound as a data stream.
Formal definition
In a formal way, a data stream is any ordered pair where:
is a sequence of tuples and
is a sequence of positive real time intervals.
Content
Data Stream contains different sets of data, that depend on the chosen data format.
Attributes – each attribute of the data stream represents a certain type of data, e.g. segment / data point ID, timestamp, geodata.
Timestamp attribute helps to identify when an event occurred.
Subject ID is an encoded-by-algorithm ID, that has been extracted out of a cookie.
Raw Data includes information straight from the data provider without being processed by an algorithm nor human.
Processed Data is a data that has been prepared (somehow modified, validated or cleaned), to be used for future actions.
Usage
There are various areas where data streams are used:
Fraud detection & scoring – raw data is used as source data for an anti-fraud algorithm (data analysis techniques for fraud detection). For example, timestamps, cookie occurrences or analysis of data points are used within the scoring system to detect fraud or to make sure that a message receiver is not a bot (so-called Non-Human Traffic).
Artificial intelligence – raw data is treated like a train set and a test set during AI and machine learning algorithms building.
Raw data is used for profiling and personalization to customize user profiles and divide them for segmentation, e.g., per gender or location (based on data point).
Business intelligence – raw data is a source of information for BI systems, used for enriching user profiles with detailed information about them, e.g., purchase path or geodata. This information is used for business analysis and predictive research.
Targeting – processed data by data scientists improve online campaigns and is used for reaching the target audience.
CRM Enrichment – raw data is integrated with customer-relationship management system. CRM integration allows to fill the gaps in users' profiles with demographic data, interests or buying intentions.
Integration
Core integrations with data streams are:
Data streams are integrated with systems such as customer data platform (CDP), customer relationship management (CRM) or data management platform (DMP) to enrich users' profiles with external data. It is possible to expand the knowledge about existing users by using external sources.
Data streams are used to enrich business intelligence systems and make analysis more precise and conclusions more accurate.
In the case of content management system (CMS) integration, Data Stream is used to ide |
https://en.wikipedia.org/wiki/Roguelike | Roguelike (or rogue-like) is a subgenre of role-playing computer games traditionally characterized by a dungeon crawl through procedurally generated levels, turn-based gameplay, grid-based movement, and permanent death of the player character. Most roguelikes are based on a high fantasy narrative, reflecting their influence from tabletop role playing games such as Dungeons & Dragons.
Though Beneath Apple Manor predates it, the 1980 game Rogue, which is an ASCII based game that runs in terminal or terminal emulator, is considered the forerunner and the namesake of the genre, with derivative games mirroring Rogues character- or sprite-based graphics. These games were popularized among college students and computer programmers of the 1980s and 1990s, leading to hundreds of variants. Some of the better-known variants include Hack, NetHack, Ancient Domains of Mystery, Moria, Angband, Tales of Maj'Eyal, and Dungeon Crawl Stone Soup. The Japanese series of Mystery Dungeon games by Chunsoft, inspired by Rogue, also fall within the concept of roguelike games.
The exact definition of a roguelike game remains a point of debate in the video game community. A "Berlin Interpretation" drafted in 2008 defined a number of high- and low-value factors that distinguished the "pure" roguelike games Rogue, NetHack and Angband from edge cases like Diablo. Since then, with more powerful home computers and gaming systems and the rapid growth of indie video game development, several new "roguelikes" have appeared, with some but not all of these high-value factors, nominally the use of procedural generation and permadeath, while often incorporating other gameplay genres, thematic elements, and graphical styles; common examples of these include Spelunky, FTL: Faster Than Light, The Binding of Isaac, Slay the Spire and Hades. To distinguish these from traditional roguelikes, such games may be referred to as "rogue-lite" or "roguelike-like".
Origin
The term "roguelike" came from Usenet newsgroups around 1993, as this was the principal channel the players of roguelike games of that period were using to discuss these games, as well as what the developers used to announce new releases and even distribute the game's source code in some cases. With several individual groups for each game, it was suggested that with rising popularity of Rogue, Hack, Moria, and Angband, all of which shared common elements, that the groups be consolidated under an umbrella term to facilitate cross-game discussion. Debate among users of these groups ensued to try to find an encapsulating term that described the common elements, starting with rec.games.dungeon.*, but after three weeks of discussion, rec.games.roguelike.*, based on Rogue being the oldest of these types of games, was picked as "the least of all available evils". By the time it was suggested that a group be created to discuss the development of these kind of games in 1998, the "roguelike" term was already established within the communi |
https://en.wikipedia.org/wiki/Disruptive%20innovation | In business theory, disruptive innovation is innovation that creates a new market and value network or enters at the bottom of an existing market and eventually displaces established market-leading firms, products, and alliances. The term, "disruptive innovation" was popularized by the American academic Clayton Christensen and his collaborators beginning in 1995, but the concept had been previously described in Richard N. Foster's book "Innovation: The Attacker's Advantage" and in the paper Strategic Responses to Technological Threats.
Not all innovations are disruptive, even if they are revolutionary. For example, the first automobiles in the late 19th century were not a disruptive innovation, because early automobiles were expensive luxury items that did not disrupt the market for horse-drawn vehicles. The market for transportation essentially remained intact until the debut of the lower-priced Ford Model T in 1908. The mass-produced automobile was a disruptive innovation, because it changed the transportation market, whereas the first thirty years of automobiles did not.
Disruptive innovations tend to be produced by outsiders and entrepreneurs in startups, rather than existing market-leading companies. The business environment of market leaders does not allow them to pursue disruptive innovations when they first arise, because they are not profitable enough at first and because their development can take scarce resources away from sustaining innovations (which are needed to compete against current competition). Small teams are more likely to create disruptive innovations than large teams. A disruptive process can take longer to develop than by the conventional approach and the risk associated to it is higher than the other more incremental, architectural or evolutionary forms of innovations, but once it is deployed in the market, it achieves a much faster penetration and higher degree of impact on the established markets.
Beyond business and economics disruptive innovations can also be considered to disrupt complex systems, including economic and business-related aspects. Through identifying and analyzing systems for possible points of intervention, one can then design changes focused on disruptive interventions.
Usage history
The term disruptive technologies was coined by Clayton M. Christensen and introduced in his 1995 article Disruptive Technologies: Catching the Wave, which he cowrote with Joseph Bower. The article is aimed at both management executives who make the funding or purchasing decisions in companies, as well as the research community, which is largely responsible for introducing the disruptive vector to the consumer market. He describes the term further in his book The Innovator's Dilemma. Innovator's Dilemma explored the case of the disk drive industry (the disk drive and memory industry, with its rapid technological evolution, is to the study of technology what fruit flies are to the study of genetics, as Christensen was |
https://en.wikipedia.org/wiki/Upload | Uploading refers to transmitting data from one computer system to another through means of a network. Common methods of uploading include: uploading via web browsers, FTP clients], and terminals (SCP/SFTP). Uploading can be used in the context of (potentially many) clients that send files to a central server. While uploading can also be defined in the context of sending files between distributed clients, such as with a peer-to-peer (P2P) file-sharing protocol like BitTorrent, the term file sharing is more often used in this case. Moving files within a computer system, as opposed to over a network, is called file copying.
Uploading directly contrasts with downloading, where data is received over a network. In the case of users uploading files over the internet, uploading is often slower than downloading as many internet service providers (ISPs) offer asymmetric connections, which offer more network bandwidth for downloading than uploading.
Definition
To transfer something (such as data or files), from a computer or other digital device to the memory of another device (such as a larger or remote computer) especially via the internet.
Historical development
Remote file sharing first came into fruition in January 1978, when Ward Christensen and Randy Suess, who were members of the Chicago Area Computer Hobbyists' Exchange (CACHE), created the Computerized Bulletin Board System (CBBS). This used an early file transfer protocol (MODEM, later XMODEM) to send binary files via a hardware modem, accessible by another modem via a telephone number.
In the following years, new protocols such as Kermit were released, until the File Transfer Protocol (FTP) was standardized 1985 (). FTP is based on TCP/IP and gave rise to many FTP clients, which, in turn, gave users all around the world access to the same standard network protocol to transfer data between devices.
The transfer of data saw a significant increase in popularity after the release of the World Wide Web in 1991, which, for the first time, allowed users who were not computer hobbyists to easily share files, directly from their web browser over HTTP.
Resumability of file transfers
Transfers became more reliable with the launch of HTTP/1.1 in 1997 (), which gave users the option to resume downloads that were interrupted, for instance due to unreliable connections. Before web browsers widely rolled out support, software programs like GetRight could be used to resume downloads. Resuming uploads is not currently supported by HTTP, but can be added with the Tus open protocol for resumable file uploads, which layers resumability of uploads on top of existing HTTP connections.
Types of uploading
Client-to-server uploading
Transmitting a local file to a remote system following the client–server model, e.g., a web browser transferring a video to a website, is called client-to-server uploading.
Remote uploading
Transferring data from one remote system to another remote system under the control of a loc |
https://en.wikipedia.org/wiki/Authentication | Authentication (from authentikos, "real, genuine", from αὐθέντης authentes, "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicating a person or thing's identity, authentication is the process of verifying that identity. It might involve validating personal identity documents, verifying the authenticity of a website with a digital certificate, determining the age of an artifact by carbon dating, or ensuring that a product or document is not counterfeit.
Methods
Authentication is relevant to multiple fields. In art, antiques, and anthropology, a common problem is verifying that a given artifact was produced by a certain person or in a certain place or period of history. In computer science, verifying a user's identity is often required to allow access to confidential data or systems.
Authentication can be considered to be of three types:
The first type of authentication is accepting proof of identity given by a credible person who has first-hand evidence that the identity is genuine. When authentication is required of art or physical objects, this proof could be a friend, family member, or colleague attesting to the item's provenance, perhaps by having witnessed the item in its creator's possession. With autographed sports memorabilia, this could involve someone attesting that they witnessed the object being signed. A vendor selling branded items implies authenticity, while they may not have evidence that every step in the supply chain was authenticated. Centralized authority-based trust relationships back most secure internet communication through known public certificate authorities; decentralized peer-based trust, also known as a web of trust, is used for personal services such as email or files and trust is established by known individuals signing each other's cryptographic key for instance.
The second type of authentication is comparing the attributes of the object itself to what is known about objects of that origin. For example, an art expert might look for similarities in the style of painting, check the location and form of a signature, or compare the object to an old photograph. An archaeologist, on the other hand, might use carbon dating to verify the age of an artifact, do a chemical and spectroscopic analysis of the materials used, or compare the style of construction or decoration to other artifacts of similar origin. The physics of sound and light, and comparison with a known physical environment, can be used to examine the authenticity of audio recordings, photographs, or videos. Documents can be verified as being created on ink or paper readily available at the time of the item's implied creation.
Attribute comparison may be vulnerable to forgery. In general, it relies on the facts that creating a forgery indistinguishable from a genuine artifact requires expert knowledge, that mistakes are easily made, and that the amount of effort |
https://en.wikipedia.org/wiki/Routing%20table | In computer networking, a routing table, or routing information base (RIB), is a data table stored in a router or a network host that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes. The routing table contains information about the topology of the network immediately around it.
The construction of routing tables is the primary goal of routing protocols. Static routes are entries that are fixed, rather than resulting from routing protocols and network topology discovery procedures.
Overview
A routing table is analogous to a distribution map in package delivery. Whenever a node needs to send data to another node on a network, it must first know where to send it. If the node cannot directly connect to the destination node, it has to send it via other nodes along a route to the destination node. Each node needs to keep track of which way to deliver various packages of data, and for this it uses a routing table. A routing table is a database that keeps track of paths, like a map, and uses these to determine which way to forward traffic. A routing table is a data file in RAM that is used to store route information about directly connected and remote networks. Nodes can also share the contents of their routing table with other nodes.
The primary function of a router is to forward a packet toward its destination network, which is the destination IP address of the packet. To do this, a router needs to search the routing information stored in its routing table. The routing table contains network/next hop associations. These associations tell a router that a particular destination can be optimally reached by sending the packet to a specific router that represents the next hop on the way to the final destination. The next hop association can also be the outgoing or exit interface to the final destination.
With hop-by-hop routing, each routing table lists, for all reachable destinations, the address of the next device along the path to that destination: the next hop. Assuming that the routing tables are consistent, the simple algorithm of relaying packets to their destination's next hop thus suffices to deliver data anywhere in a network. Hop-by-hop is the fundamental characteristic of the IP Internet layer and the OSI Network Layer.
When a router interface is configured with an IP address and subnet mask, the interface becomes a host on that attached network. A directly connected network is a network that is directly attached to one of the router interfaces. The network address and subnet mask of the interface, along with the interface type and number, are entered into the routing table as a directly connected network.
A remote network is a network that can only be reached by sending the packet to another router. Routing table entries to remote networks may be either dynamic or static. Dynamic routes are routes to remote networks that were learned automatically by the router thr |
https://en.wikipedia.org/wiki/Fibonacci%20coding | In mathematics and computing, Fibonacci coding is a universal code which encodes positive integers into binary code words. It is one example of representations of integers based on Fibonacci numbers. Each code word ends with "11" and contains no other instances of "11" before the end.
The Fibonacci code is closely related to the Zeckendorf representation, a positional numeral system that uses Zeckendorf's theorem and has the property that no number has a representation with consecutive 1s. The Fibonacci code word for a particular integer is exactly the integer's Zeckendorf representation with the order of its digits reversed and an additional "1" appended to the end.
Definition
For a number , if represent the digits of the code word representing then we have:
where is the th Fibonacci number, and so is the th distinct Fibonacci number starting with . The last bit is always an appended bit of 1 and does not carry place value.
It can be shown that such a coding is unique, and the only occurrence of "11" in any code word is at the end i.e. d(k−1) and d(k). The penultimate bit is the most significant bit and the first bit is the least significant bit. Also leading zeros cannot be omitted as they can in e.g. decimal numbers.
The first few Fibonacci codes are shown below, and also their so-called implied probability, the value for each number that has a minimum-size code in Fibonacci coding.
To encode an integer N:
Find the largest Fibonacci number equal to or less than N; subtract this number from N, keeping track of the remainder.
If the number subtracted was the ith Fibonacci number F(i), put a 1 in place i−2 in the code word (counting the left most digit as place 0).
Repeat the previous steps, substituting the remainder for N, until a remainder of 0 is reached.
Place an additional 1 after the rightmost digit in the code word.
To decode a code word, remove the final "1", assign the remaining the values 1,2,3,5,8,13... (the Fibonacci numbers) to the bits in the code word, and sum the values of the "1" bits.
Comparison with other universal codes
Fibonacci coding has a useful property that sometimes makes it attractive in comparison to other universal codes: it is an example of a self-synchronizing code, making it easier to recover data from a damaged stream. With most other universal codes, if a single bit is altered, none of the data that comes after it will be correctly read. With Fibonacci coding, on the other hand, a changed bit may cause one token to be read as two, or cause two tokens to be read incorrectly as one, but reading a "0" from the stream will stop the errors from propagating further. Since the only stream that has no "0" in it is a stream of "11" tokens, the total edit distance between a stream damaged by a single bit error and the original stream is at most three.
This approach—encoding using sequence of symbols, in which some patterns (like "11") are forbidden, can be freely generalized.
Example
The followi |
https://en.wikipedia.org/wiki/Basic | Basic or BASIC may refer to:
Science and technology
BASIC, a computer programming language
Basic (chemistry), having the properties of a base
Basic access authentication, in HTTP
Entertainment
Basic (film), a 2003 film
Basic, one of the languages in Star Wars
Music
Basic (Glen Campbell album), 1978
Basic (Robert Quine and Fred Maher album), 1984
B.A.S.I.C. (Alpinestars album), 2000
Basic (Brown Eyed Girls album), 2015
B.A.S.I.C. (The Basics album), 2019
Places
Basic, Mississippi, a community in the US
BASIC countries, Brazil, South Africa, India and China in climate change negotiations
Organizations
BASIC Bank Limited, government owned bank in Bangladesh
Basic Books, an American publisher
Other uses
Basic (cigarette), a brand of cigarettes manufactured by the Altria Group (Philip Morris Company)
Basic (dance move), the dance move that defines the character of a particular dance
Basic (slang), a "mainstream woman" in American popular culture
British American Security Information Council, a think tank based in London
Bašić, South Slavic surname
BASIC countries
See also
Basic English, an English-based controlled language with a limited vocabulary
Visual Basic (classic), a computer programming language
Visual Basic .NET, a computer programming language based on the .NET Framework
Basics (disambiguation)
Base (disambiguation)
Bassic (Martin "Bassic" Lindhe, born 1971), Swedish musician and composer
Basis (disambiguation) |
https://en.wikipedia.org/wiki/Mac | Mac or MAC may refer to:
Common meanings
Mac (computer), a line of personal computers made by Apple Inc.
Mackintosh, a raincoat made of rubberized cloth
Mac, a prefix to surnames derived from Gaelic languages
McIntosh (apple), a Canadian apple cultivar
Arts and entertainment
Fictional entities
Mac (Green Wing), a television character
Mac (It's Always Sunny in Philadelphia), a television character
Mac Gargan, an enemy of Spider-Man
Mac, a character on Foster's Home for Imaginary Friends
Angus "Mac" MacGyver, from the television series MacGyver
Cindy "Mac" Mackenzie, from the TV series Veronica Mars
Lt. Col. Sarah MacKenzie, from the TV series JAG
Dr. Terrence McAfferty, from Robert Muchamore's CHERUB and Henderson's Boys novel series
Mac McAnnally, in The Dresden Files series
Randle McMurphy, in the movie One Flew Over the Cuckoo's Nest
Mac Taylor, from the TV series CSI: NY
Mac, a canine character in the television series Clifford the Big Red Dog
Monster Attack Crew, a fictional pilot squadron in the television series Ultraman Leo
MAC (Mysterious Alien Creature), the titular character in the 1988 film Mac and Me
Mac (Makrand Deendayal Chatpatiya), portrayed by Akshay Kumar in the 2005 Indian comedy film Garam Masala
Other uses in arts and entertainment
Mac (film), 1992, directed by and starring John Turturro
Mac (novel), by John MacLean
Mac the Moose, a public statue in Moose Jaw, Saskatchewan, Canada; formerly the World's Largest Moose
Mac, a Sports Beanie Baby cardinal produced by Ty, Inc. in 1999
MAC Awards, for achievements in cabaret, comedy, and jazz, administered by the Manhattan Association of Cabarets & Clubs
Business and economics
Business terminology
Marginal Abatement Cost, a concept in environmental economics
Material adverse change, a provision in mergers and acquisitions contracts and venture financing agreements
Businesses
MAC Cosmetics, a cosmetics brand, stylized as M•A•C
Mac Para Technology, a Czech aircraft manufacturer
Macerich, an American real estate investment trust (NYSE stock symbol MAC)
Manufacture d'armes de Châtellerault, a French state arms manufacturer
Martin's Air Charter, now Martinair, an airline
Medicare Administrative Contractor, a private company contracted to administer Medicare benefits in the U.S.
Military Armament Corporation, manufacturer of the MAC-10 and MAC-11 pistols
Morgan Advanced Ceramics, a ceramics manufacturing company
Codes
MAC, the ISO 3166 code for Macau, a special administrative region of the People's Republic of China
MAC, Amtrac station code for Macomb (Amtrak station), Illinois, United States
mac, an ISO 639-2 code for the Macedonian language
Organizations
Government and military agencies
Mainland Affairs Council, an agency under the Executive Yuan of the Republic of China
Metropolitan Airports Commission, the operator of airports in the Minneapolis-St. Paul area
Military Affairs Commission in China; see Central Military Commission ( |
https://en.wikipedia.org/wiki/Proxy%20ARP | Proxy ARP is a technique by which a proxy server on a given network answers the Address Resolution Protocol (ARP) queries for an IP address that is not on that network. The proxy is aware of the location of the traffic's destination and offers its own MAC address as the (ostensibly final) destination. The traffic directed to the proxy address is then typically routed by the proxy to the intended destination via another interface or via a tunnel.
The process, which results in the proxy server responding with its own MAC address to an ARP request for a different IP address for proxying purposes, is sometimes referred to as publishing.
Uses
Below are some typical uses for proxy ARP:
Joining a broadcast LAN with serial links (e.g., dialup or VPN connections).
Assume an Ethernet broadcast domain (e.g., a group of stations connected to the same hub or switch (VLAN)) using a certain IPv4 address range (e.g., 192.168.0.0/24, where 192.168.0.1 – 192.168.0.127 are assigned to wired nodes). One or more of the nodes is an access router accepting dialup or VPN connections. The access router gives the dial-up nodes IP addresses in the range 192.168.0.128 – 192.168.0.254; for this example, assume a dial-up node gets IP address 192.168.0.254.
The access router uses proxy ARP to make the dial-up node present in the subnet without being wired into the Ethernet: the access router 'publishes' its own MAC address for 192.168.0.254. Now, when another node wired into the Ethernet wants to talk to the dial-up node, it will ask on the network for the MAC address of 192.168.0.254 and find the access router's MAC address. It will therefore send its IP packets to the access router, and the access router will know to pass them on to the particular dial-up node. All dial-up nodes therefore appear to the wired Ethernet nodes as if they are wired into the same Ethernet subnet.
Taking multiple addresses from a LAN
Assume a station (e.g., a server) with an interface (10.0.0.2) connected to a network (10.0.0.0/24). Certain applications may require multiple IP addresses on the server. Provided the addresses have to be from the 10.0.0.0/24 range, the way the problem is solved is through proxy ARP. Additional addresses (say, 10.0.0.230-10.0.0.240) are aliased to the loopback interface of the server (or assigned to special interfaces, the latter typically being the case with VMware/UML/jails/vservers/other virtual server environments) and 'published' on the 10.0.0.2 interface (although many operating systems allow direct allocation of multiple addresses to one interface, thus eliminating the need for such workarounds).
On a firewall
In this scenario a firewall can be configured with a single IP address. One simple example of a use for this would be placing a firewall in front of a single host or group of hosts on a subnetwork. Example: A network (10.0.0.0/8) has a server (10.0.0.20) that should be protected. A proxy ARP firewall can be placed in front of the server. In this way |
https://en.wikipedia.org/wiki/Microcomputer | A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PCB). Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors. The predecessors to these computers, mainframes and minicomputers, were comparatively much larger and more expensive (though indeed present-day mainframes such as the IBM System z machines use one or more custom microprocessors as their CPUs). Many microcomputers (when equipped with a keyboard and screen for input and output) are also personal computers (in the generic sense). An early use of the term "personal computer" in 1962 predates microprocessor-based designs. (See "Personal Computer: Computers at Companies" reference below). A "microcomputer" used as an embedded control system may have no human-readable input and output devices. "Personal computer" may be used generically or may denote an IBM PC compatible machine.
The abbreviation "micro" was common during the 1970s and 1980s, but has since fallen out of common usage.
Origins
The term microcomputer came into popular use after the introduction of the minicomputer, although Isaac Asimov used the term in his short story "The Dying Night" as early as 1956 (published in The Magazine of Fantasy and Science Fiction in July that year). Most notably, the microcomputer replaced the many separate components that made up the minicomputer's CPU with one integrated microprocessor chip.
In 1973, the French Institut National de la Recherche Agronomique (INRA) was looking for a computer able to measure agricultural hygrometry. To answer this request, a team of French engineers of the computer technology company R2E, led by its Head of Development, François Gernelle, created the first available microprocessor-based microcomputer, the Micral N. The same year the company filed their patents with the term "Micro-ordinateur", a literal equivalent of "Microcomputer", to designate a solid state machine designed with a microprocessor.
In the US the earliest models such as the Altair 8800 were often sold as kits to be assembled by the user, and came with as little as 256 bytes of RAM, and no input/output devices other than indicator lights and switches, useful as a proof of concept to demonstrate what such a simple device could do.
As microprocessors and semiconductor memory became less expensive, microcomputers grew cheaper and easier to use.
Increasingly inexpensive logic chips such as the 7400 series allowed cheap dedicated circuitry for improved user interfaces such as keyboard input, instead of simply a row of switches to toggle bits one at a time.
Use of audio cassettes for inexpensive data storage replaced manual re-entry of a program every time the device was powered on.
Large cheap arrays of silicon logic gates in the form of read-only memory a |
https://en.wikipedia.org/wiki/Fractal%20art | Fractal art is a form of algorithmic art created by calculating fractal objects and representing the calculation results as still digital images, animations, and media. Fractal art developed from the mid-1980s onwards. It is a genre of computer art and digital art which are part of new media art. The mathematical beauty of fractals lies at the intersection of generative art and computer art. They combine to produce a type of abstract art.
Fractal art (especially in the western world) is rarely drawn or painted by hand. It is usually created indirectly with the assistance of fractal-generating software, iterating through three phases: setting parameters of appropriate fractal software; executing the possibly lengthy calculation; and evaluating the product. In some cases, other graphics programs are used to further modify the images produced. This is called post-processing. Non-fractal imagery may also be integrated into the artwork. The Julia set and Mandelbrot sets can be considered as icons of fractal art.
It was assumed that fractal art could not have developed without computers because of the calculative capabilities they provide. Fractals are generated by applying iterative methods to solving non-linear equations or polynomial equations. Fractals are any of various extremely irregular curves or shapes for which any suitably chosen part is similar in shape to a given larger or smaller part when magnified or reduced to the same size.
Types
There are many different kinds of fractal images. They can be subdivided into several groups.
Fractals derived from standard geometry by using iterative transformations on an initial common figure like a straight line (the Cantor dust or the von Koch curve), a triangle (the Sierpinski triangle), or a cube (the Menger sponge). The first fractal figures invented near the end of the 19th and early 20th centuries belong to this group.
IFS (iterated function systems)
Strange attractors
Fractal flame
L-system fractals
Fractals created by the iteration of complex polynomials: perhaps the most famous fractals.
Newton fractals, including Nova fractals
Quaternionic and (recently) hypernionic fractals
Fractal terrains generated by random fractal processes
Mandelbulbs are a kind of three dimensional fractal.
Fractal Expressionism is a term used to differentiate traditional visual art that incorporates fractal elements such as self-similarity for example. Perhaps the best example of fractal expressionism is found in Jackson Pollock's dripped patterns. They have been analysed and found to contain a fractal dimension which has been attributed to his technique.
Techniques
Fractals of all kinds have been used as the basis for digital art and animation. High resolution color graphics became increasingly available at scientific research labs in the mid-1980s. Scientific forms of art, including fractal art, have developed separately from mainstream culture. Starting with 2-dimensional details of fractals, |
https://en.wikipedia.org/wiki/CT | CT or ct may refer to:
In arts and media
c't (Computer Technik), a German computer magazine
Freelancer Agent Connecticut (C.T.), a fictional character in the web series Red vs. Blue
Christianity Today, an American evangelical Christian magazine
Businesses and organizations
CT Corp, an Indonesian conglomerate
CT Corporation, an umbrella brand for two businesses: CT Corporation and CT Liena
C/T Group, formerly Crosby Textor Group, social research and political polling company
Canadian Tire, a Canadian company engaged in retailing, financial services and petroleum
Calgary Transit, the public transit service in Calgary, Alberta, Canada
Central Trains (National Rail abbreviation), a former train operating company in the United Kingdom
Česká televize, the public television broadcaster in the Czech Republic
Community Transit, the public transit service in Snohomish County, Washington, U.S.
Comunión Tradicionalista, a former Spanish political party
CT (TV channel), a Filipino cable and satellite television network
Finance
Centime (ct), the French for "cent", used in English in several Francophone countries
Stotinki (ст), the currency of Bulgaria
Places
CT postcode area, for Canterbury and surrounding areas in south-eastern England
Connecticut (United States postal abbreviation)
Province of Catania (vehicle registration code), Sicily, Italy
Central African Republic (FIPS Pub 10-4 code and obsolete NATO diagram)
Canton and Enderbury Islands (obsolete ISO 3166 country code), part of the Phoenix Islands in the Pacific Ocean
Cape Town (capital city of the Western Cape, South Africa)
Ct, for "Court"; a street suffix as used in the US
Science and technology
Biology and medicine
Haplogroup CT, Y-DNA haplogroup.
CT scan or X-ray computed tomography, a medical imaging method
Calcitonin (symbol CT), a hormone produced in the thyroid gland
Calibrated automated thrombogram (CT or CAT), a coagulation test
Cardiothoracic surgery, the field of medicine specializing in chest surgery
Chemotype (ct.), a chemically distinct entity in a plant or microorganism
Cognitive therapy, a type of psychotherapy
Connective tissue, a type of biological tissue
Chelation therapy
Chemotherapy
Cholera toxin, a toxic protein secreted by Vibrio cholerae
Threshold Cycle (Ct), see cycle of quantification/qualification
COVID-19 test
Computing
Intel Ct, a SIMD multithreading programming model developed by Intel
Certificate Transparency, in network security
Other uses in science and technology
CT Value, in drinking water disinfection
Threshold cycle (Ct), a measure in the cycle of quantification/qualification of a real-time polymerase chain reaction
Carat (purity) (ct), a measure of the purity of gold and platinum alloys
Carat (mass) (ct), a unit of mass used for measuring gems and pearls
Continuous-time signal, a varying quantity (a signal) whose domain is a continuum
Center tap, a wire that is connected halfway along one of the windings of a t |
https://en.wikipedia.org/wiki/Triple%20DES | In cryptography, Triple DES (3DES or TDES), officially the Triple Data Encryption Algorithm (TDEA or Triple DEA), is a symmetric-key block cipher, which applies the DES cipher algorithm three times to each data block. The Data Encryption Standard's (DES) 56-bit key is no longer considered adequate in the face of modern cryptanalytic techniques and supercomputing power. A CVE released in 2016, CVE-2016-2183 disclosed a major security vulnerability in DES and 3DES encryption algorithms. This CVE, combined with the inadequate key size of DES and 3DES, led to NIST deprecating DES and 3DES for new applications in 2017, and for all applications by the end of 2023. It has been replaced with the more secure, more robust AES.
While the government and industry standards abbreviate the algorithm's name as TDES (Triple DES) and TDEA (Triple Data Encryption Algorithm), RFC 1851 referred to it as 3DES from the time it first promulgated the idea, and this namesake has since come into wide use by most vendors, users, and cryptographers.
History
In 1978, a triple encryption method using DES with two 56-bit keys was proposed by Walter Tuchman; in 1981 Merkle and Hellman proposed a more secure triple key version of 3DES with 112 bits of security.
Standards
The Triple Data Encryption Algorithm is variously defined in several standards documents:
RFC 1851, The ESP Triple DES Transform (approved in 1995)
ANSI ANS X9.52-1998 Triple Data Encryption Algorithm Modes of Operation (approved in 1998, withdrawn in 2008)
FIPS PUB 46-3 Data Encryption Standard (DES) (approved in 1999, withdrawn in 2005)
NIST Special Publication 800-67 Revision 2 Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher (approved in 2017)
ISO/IEC 18033-3:2010: Part 3: Block ciphers (approved in 2005)
Algorithm
The original DES cipher's key size of 56 bits was generally sufficient when that algorithm was designed, but the availability of increasing computational power made brute-force attacks feasible. Triple DES provides a relatively simple method of increasing the key size of DES to protect against such attacks, without the need to design a completely new block cipher algorithm.
A naive approach to increase strength of a block encryption algorithm with short key length (like DES) would be to use two keys instead of one, and encrypt each block twice: . If the original key length is bits, one would hope this scheme provides security equivalent to using key bits long. Unfortunately, this approach is vulnerable to meet-in-the-middle attack: given a known plaintext pair , such that , one can recover the key pair in steps, instead of the steps one would expect from an ideally secure algorithm with bits of key.
Therefore, Triple DES uses a "key bundle" that comprises three DES keys, , and , each of 56 bits (excluding parity bits). The encryption algorithm is:
That is, DES encrypt with , DES decrypt with , then DES encrypt with .
Decryption is the reverse:
T |
https://en.wikipedia.org/wiki/Internet%20backbone | The Internet backbone may be defined by the principal data routes between large, strategically interconnected computer networks and core routers of the Internet. These data routes are hosted by commercial, government, academic and other high-capacity network centers, as well as the Internet exchange points and network access points, that exchange Internet traffic between the countries, continents, and across the oceans. Internet service providers, often Tier 1 networks, participate in Internet backbone traffic by privately negotiated interconnection agreements, primarily governed by the principle of settlement-free peering.
The Internet, and consequently its backbone networks, do not rely on central control or coordinating facilities, nor do they implement any global network policies. The resilience of the Internet results from its principal architectural features, most notably the idea of placing as few network state and control functions as possible in the network elements and instead relying on the endpoints of communication to handle most of the processing to ensure data integrity, reliability, and authentication. In addition, the high degree of redundancy of today's network links and sophisticated real-time routing protocols provide alternate paths of communications for load balancing and congestion avoidance.
The largest providers, known as Tier 1 networks, have such comprehensive networks that they do not purchase transit agreements from other providers.
Infrastructure
The Internet backbone consists of many networks owned by numerous companies. Optical fiber trunk lines consist of many fiber cables bundled to increase capacity, or bandwidth. Fiber-optic communication remains the medium of choice for Internet backbone providers for several reasons. Fiber-optics allow for fast data speeds and large bandwidth, they suffer relatively little attenuation, allowing them to cover long distances with few repeaters, and they are also immune to crosstalk and other forms of electromagnetic interference which plague electrical transmission. The real-time routing protocols and redundancy built into the backbone is also able to reroute traffic in case of a failure. The data rates of backbone lines have increased over time. In 1998, all of the United States' backbone networks had utilized the slowest data rate of 45 Mbit/s. However, technological improvements allowed for 41 percent of backbones to have data rates of 2,488 Mbit/s or faster by the mid 2000s.
History
The first packet-switched computer networks, the NPL network and the ARPANET were interconnected in 1973 via University College London. The ARPANET used a backbone of routers called Interface Message Processors. Other packet-switched computer networks proliferated starting in the 1970s, eventually adopting TCP/IP protocols, or being replaced by newer networks. The National Science Foundation created the National Science Foundation Network (NSFNET) in 1986 by funding six networking sites us |
https://en.wikipedia.org/wiki/ArtCyclopedia | Artcyclopedia is an online database of museum-quality fine art founded by Canadian John Malyon.
Information
The Artcyclopedia only deals with art that can be viewed online, and indexes 2,300 art sites (from museums and galleries), with links to around 180,000 artworks by 8,500 artists. The site has also started to compile a list of art galleries and auction houses.
See also
The Artchive
Web Gallery of Art
WebMuseum
References
External links
of Artcyclopedia – the fine art search engine
Art websites
Virtual art museums and galleries
Scholarly search services
Arts databases
Online databases |
https://en.wikipedia.org/wiki/Sendmail | Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.
A descendant of the delivermail program written by Eric Allman, Sendmail is a well-known project of the free and open source software and Unix communities. It has spread both as free software and proprietary software.
Overview
Allman wrote the original ARPANET delivermail which shipped in 1979 with 4.0 and 4.1 BSD. He wrote Sendmail as a derivative of delivermail in the early 1980s at UC Berkeley. It shipped with BSD 4.1c in 1983, the first BSD version that included TCP/IP protocols.
In 1996, approximately 80% of the publicly reachable mail-servers on the Internet ran Sendmail. More recent surveys have suggested a decline, with 3.64% of mail servers in March 2021 detected as running Sendmail in a study performed by E-Soft, Inc. A previous survey (December 2007 or earlier) reported 24% of mail servers running Sendmail according to a study performed by Mail Radar.
Allman designed Sendmail to incorporate great flexibility, but it can be daunting to configure for novices. Standard configuration packages delivered with the source code distribution require the use of the M4 macro language which hides much of the configuration complexity. The configuration defines the site-local mail delivery options and their access parameters, the mechanism of forwarding mail to remote sites, as well as many application tuning parameters.
Sendmail supports a variety of mail transfer protocols, including SMTP, DECnet's Mail-11, HylaFAX, QuickPage and UUCP. Additionally, Sendmail v8.12 introduced support for milters - external mail filtering programs that can participate in each step of the SMTP conversation.
Acquisition by Proofpoint, Inc.
Sendmail, Inc was acquired by Proofpoint, Inc. This announcement was released on 1 October 2013.
Security
Sendmail originated in the early days of the Internet, an era when considerations of security did not play a primary role in the development of network software. Early versions of Sendmail suffered from a number of security vulnerabilities that have been corrected over the years.
Sendmail itself incorporated a certain amount of privilege separation in order to avoid exposure to security issues. , current versions of Sendmail, like other modern MTAs, incorporate a number of security improvements and optional features that can be configured to improve security and help prevent abuse.
History of vulnerabilities
Sendmail vulnerabilities in CERT advisories and alerts:
The UNIX-HATERS Handbook dedicated an entire chapter to perceived problems and weaknesses of sendmail.
Implementation
As of sendmail release 8.12.0 the default implementation of sendmail runs as the Unix user smmsp — the sendmail message submission program.
See also
List of mail servers
Comparison of mail servers
Ma |
https://en.wikipedia.org/wiki/Computer%20number%20format | A computer number format is the internal representation of numeric values in digital device hardware and software, such as in programmable computers and calculators. Numerical values are stored as groupings of bits, such as bytes and words. The encoding between numerical values and bit patterns is chosen for convenience of the operation of the computer; the encoding used by the computer's instruction set generally requires conversion for external use, such as for printing and display. Different types of processors may have different internal representations of numerical values and different conventions are used for integer and real numbers. Most calculations are carried out with number formats that fit into a processor register, but some software systems allow representation of arbitrarily large numbers using multiple words of memory.
Binary number representation
Computers represent data in sets of binary digits. The representation is composed of bits, which in turn are grouped into larger sets such as bytes.
A bit is a binary digit that represents one of two states. The concept of a bit can be understood as a value of either 1 or 0, on or off, yes or no, true or false, or encoded by a switch or toggle of some kind.
While a single bit, on its own, is able to represent only two values, a string of bits may be used to represent larger values. For example, a string of three bits can represent up to eight distinct values as illustrated in Table 1.
As the number of bits composing a string increases, the number of possible 0 and 1 combinations increases exponentially. A single bit allows only two value-combinations, two bits combined can make four separate values, three bits for eight, and so on, increasing with the formula 2n. The amount of possible combinations doubles with each binary digit added as illustrated in Table 2.
Groupings with a specific number of bits are used to represent varying things and have specific names.
A byte is a bit string containing the number of bits needed to represent a character. On most modern computers, this is an eight bit string. Because the definition of a byte is related to the number of bits composing a character, some older computers have used a different bit length for their byte. In many computer architectures, the byte is the smallest addressable unit, the atom of addressability, say. For example, even though 64-bit processors may address memory sixty-four bits at a time, they may still split that memory into eight-bit pieces. This is called byte-addressable memory. Historically, many CPUs read data in some multiple of eight bits. Because the byte size of eight bits is so common, but the definition is not standardized, the term octet is sometimes used to explicitly describe an eight bit sequence.
A nibble (sometimes nybble), is a number composed of four bits. Being a half-byte, the nibble was named as a play on words. A person may need several nibbles for one bite from something; similar |
https://en.wikipedia.org/wiki/GNU%20Octave | GNU Octave is a high-level programming language primarily intended for scientific computing and numerical computation. Octave helps in solving linear and nonlinear problems numerically, and for performing other numerical experiments using a language that is mostly compatible with MATLAB. It may also be used as a batch-oriented language. As part of the GNU Project, it is free software under the terms of the GNU General Public License.
History
The project was conceived around 1988. At first it was intended to be a companion to a chemical reactor design course. Full development was started by John W. Eaton in 1992. The first alpha release dates back to 4 January 1993 and on 17 February 1994 version 1.0 was released. Version 7.1.0 was released on Apr 6, 2022.
The program is named after Octave Levenspiel, a former professor of the principal author. Levenspiel was known for his ability to perform quick back-of-the-envelope calculations.
Development history
Developments
In addition to use on desktops for personal scientific computing, Octave is used in academia and industry. For example, Octave was used on a massive parallel computer at Pittsburgh Supercomputing Center to find vulnerabilities related to guessing social security numbers.
Acceleration with OpenCL or CUDA is also possible with use of GPUs.
Technical details
Octave is written in C++ using the C++ standard library.
Octave uses an interpreter to execute the Octave scripting language.
Octave is extensible using dynamically loadable modules.
Octave interpreter has an OpenGL-based graphics engine to create plots, graphs and charts and to save or print them. Alternatively, gnuplot can be used for the same purpose.
Octave includes a Graphical User Interface (GUI) in addition to the traditional command-line interface (CLI); see #User interfaces for details.
Octave, the language
The Octave language is an interpreted programming language. It is a structured programming language (similar to C) and supports many common C standard library functions, and also certain UNIX system calls and functions. However, it does not support passing arguments by reference although function arguments are copy-on-write to avoid unnecessary duplication.
Octave programs consist of a list of function calls or a script. The syntax is matrix-based and provides various functions for matrix operations. It supports various data structures and allows object-oriented programming.
Its syntax is very similar to MATLAB, and careful programming of a script will allow it to run on both Octave and MATLAB.
Because Octave is made available under the GNU General Public License, it may be freely changed, copied and used. The program runs on Microsoft Windows and most Unix and Unix-like operating systems, including Linux, Android, and macOS.
Notable features
Command and variable name completion
Typing a TAB character on the command line causes Octave to attempt to complete variable, function, and file names (similar to Bas |
https://en.wikipedia.org/wiki/Amanda%20%28software%29 | The Advanced Maryland Automatic Network Disk Archiver (Amanda) is an open source computer archiving tool that is able to back up data residing on multiple computers on a network. It uses a client–server model, where the server contacts each client to perform a backup at a scheduled time.
Amanda was initially developed at the University of Maryland and is released under a BSD-style license. Amanda is available both as a free community edition and fully supported enterprise edition. Amanda runs on almost any Unix or Unix-like systems. Amanda supports Windows systems using Samba or a native Win32 client with support for open files.
Amanda supports both tape-based and disk-based backup, and provides some useful functionality not available in other backup products. Amanda supports tape-spanning i.e. if a backup set does not fit in one tape, it will be split into multiple tapes.
Major releases
The most recent stable release is version 3.5.1, which was released on December 1, 2017.
Enterprise edition
A commercial version of Amanda was developed by the company Zmanda. It includes a management graphical user interface (GUI) and other features such as scheduler, plugin framework, and an optional cloud backup service support. The cloud backup option uses the Amazon S3 service from Amazon Web Services as the cloud storage provider and enables safe offsite storage of the Amanda backup data. The plugin framework allows for application-specific backups and is used by Amanda Enterprise to support applications such as Oracle database, Samba network share, NDMP, etc. Amanda Enterprise also supports image-level backup of live virtual machine running on VMware infrastructure.
See also
Bacula
Proxmox Backup Server
References
External links
Free backup software
Storage software
University of Maryland, College Park research projects |
https://en.wikipedia.org/wiki/Simulation%20language | A computer simulation language is used to describe the operation of a simulation on a computer. There are two major types of simulation: continuous and discrete event though more modern languages can handle more complex combinations. Most languages also have a graphical interface and at least a simple statistic gathering capability for the analysis of the results. An important part of discrete-event languages is the ability to generate pseudo-random numbers and variants from different probability distributions.
See also
Discrete event simulation
List of computer simulation software
References
Simulation programming languages
Stochastic simulation |
https://en.wikipedia.org/wiki/Guanxi | Guanxi () is a term used in Chinese culture to describe an individual's social network of mutually beneficial personal and business relationships. The character guan, 关, means “closed” and "caring" while the character xi 系 means “system” and together the term refers to a closed caring system of relationships that is somewhat analogous to the term old boy's network in the West. In Western media, the pinyin romanization guanxi is more widely used than common translations such as "connections" or "relationships" because those terms do not capture the significance of a person's guanxi to most personal and business dealings in China. Unlike in the West, guanxi relationships are almost never established purely through formal meetings but must also include spending time to get to know each other during tea sessions, dinner banquets, or other personal meetings. Essentially, guanxi requires a personal bond before any business relationship can develop. As a result, guanxi relationships are often more tightly bound than relationships in Western personal social networks. Guanxi has a major influence on the management of businesses based in mainland China and businesses owned by Overseas Chinese people in Southeast Asia (the bamboo network).
Guanxi and guanxi networks are grounded in Confucian doctrine about the proper structure of family, hierarchical, and friendly relationships in a community, including the need for implicit mutual commitments, reciprocity, and trust.
Guanxi has 3 sub-dimensions sometimes abbreviated as GRX which stands for ganqing, a measure of the emotional attachment in a relationship, renqing ( rénqíng/jen-ch'ing), the moral obligation to maintain a relationship with reciprocal exchange of favors, and xinren, or the amount of interpersonal trust. Guanxi is also related to the idea of "face" (, miànzi/mien-tzu), which refers to social status, propriety, prestige, or a combination of all three. Other related concepts include wu-lune, which supports the idea of a long term, developing relationship between a business and its client, and yi-ren and ren, which respectively support reciprocity and empathy.
History
The guanxi system developed in imperial, dynastic China. Historically, China lacked a strong rule of law and the government did not hold every citizen subject to the law. As a result, the law did not provide the same legal protection as it did in the West. Chinese people developed guanxi along with the concept of face and personal reputation to help ensure trust between each other in business and personal matters. Today, the power of guanxi resides primarily within the Chinese Communist Party (CCP).
Description and usage
In a personal context
At its most basic, guanxi describes a personal connection between two people in which one is able to prevail upon another to perform a favor or service, or be prevailed upon, that is, one's standing with another. The two people need not be of equal social status. Guanxi can also be used to |
https://en.wikipedia.org/wiki/Randal%20L.%20Schwartz | Randal L. Schwartz (born November 22, 1961), also known as merlyn, is an American author, system administrator and programming consultant. He has written several books on the Perl programming language, and plays a promotional role within the Perl community. He was a co-host of FLOSS Weekly.
In 1995, while working as a consultant for Intel, he cracked a number of passwords on the company's systems. He was convicted of hacking, sentenced to five years probation, and fined. The conviction was expunged in 2007.
Career
Schwartz is the co-author of several widely used books about Perl, a programming language, and has written regular columns about Perl for several computer magazines, including UNIX Review, Web Techniques, and the Perl Journal. He popularized the Just another Perl hacker signature programs. He is a founding board member of the Perl Mongers, the worldwide Perl grassroots advocacy organization. He was a member of the Squeak Oversight Board, which oversees the Squeak programming language.
He has owned and operated Stonehenge Consulting Services, Inc. since 1985. After joining as co-host of FLOSS Weekly, a free software/open source (FLOSS) themed podcast in 2007, he assumed the role of host in 2010 until May 2020. He has done voice work for StarShipSofa, a science-fiction podcast.
Schwartz's name is also associated with the Schwartzian transform, an algorithm to efficiently sort a list according to a computation, without repeating the computation many times for each element of the list. He also coined the name spaceship operator for use in his teaching, because it reminded him of the spaceship in an HP BASIC Star Trek game.
Schwartz is a member of the F/OSS community, and has been named a "Perl Expert" and interviewed by numerous outlets – to discuss his views on Perl, Ruby, Smalltalk and other topics – including Dr. Dobb's, Paul dot Com Security TV, The Command Line, PerlCast, FLOSS Weekly, ONLamp.com, and InfoQ. Schwartz was also a speaker at the 2011 OSCON conference and a keynote speaker at the 2010 Texas LinuxFest conference.
His various books have been met with positive reviews.
Intel case
In July 1995, Schwartz was prosecuted in the case of State of Oregon vs. Randal Schwartz, which dealt with compromised computer security during his time as a system administrator for Intel. In the process of performing penetration testing, he cracked a number of passwords on Intel's systems. Schwartz was originally convicted on three felony counts, with one reduced to a misdemeanor, but on February 1, 2007, his arrest and conviction records were sealed through an official expungement, and he is legally no longer a felon.
Bibliography
Programming Perl, ; (2ed)
Learning Perl, ; (2ed); (3ed); (4ed); (5ed); (6ed) (2011); (7ed) (2016)
Intermediate Perl, (2006); (2ed, 2012)
Learning Perl on Win32 Systems,
Learning Perl Objects, References & Modules (2003),
Effective Perl Programming,
Preface for Object Oriented Perl,
Col |
https://en.wikipedia.org/wiki/International%20E-road%20network | The international E-road network is a numbering system for roads in Europe developed by the United Nations Economic Commission for Europe (UNECE). The network is numbered from E1 up and its roads cross national borders. It also reaches Central Asian countries like Kyrgyzstan, since they are members of the UNECE.
Main international traffic arteries in Europe are defined by ECE/TRANS/SC.1/2016/3/Rev.1 which consider three types of roads: motorways, limited access roads, and ordinary roads.
In most countries, the roads carry the European route designation alongside national designations. Belgium, Norway and Sweden have roads which only have the European route designations (examples: E18 and E6). The United Kingdom, Albania and the Asian part of Russia only use national road designations and do not show the European designations at all. Andorra does not number its routes at all except in internal circumstances. Denmark only uses the European designations on signage, but also has formal names for every motorway (or part of such), by which the motorways are referred to, for instance in news and weather forecasts. In Asia, Turkey and Russia show the European designations on signage; this is not the case in many other Asian countries.
Other continents have similar international road networks, e.g., the Pan-American Highway in the Americas, the Trans-African Highway network, and the Asian Highway Network.
History
UNECE was formed in 1947, and their first major act to improve transport was a joint UN declaration no. 1264, the Declaration on the Construction of Main International Traffic Arteries, signed in Geneva on 16 September 1950, which defined the first E-road network. Originally it was envisaged that the E-road network would be a motorway system comparable to the US Interstate Highway System. The declaration was amended several times until 15 November 1975, when it was replaced by the European Agreement on Main International Traffic Arteries or "AGR", which set up a route numbering system and improved standards for roads in the list. The AGR last went through a major change in 1992 and in 2001 was extended into Central Asia to include the Caucasus nations. There were several minor revisions since, last in 2008 ().
Numbering system
The route numbering system is as follows:
Reference roads and intermediate roads, called Class-A roads, have numbers from 1 to 129.
North–south routes have odd numbers; east–west routes have even numbers. The two main exceptions are E4 and E6, both north–south routes.
The allocation of numbers progresses upwards from west to east and from north to south, with some exceptions.
Branch, link and connecting roads, called Class-B roads, have three-digit numbers above 130.
Reference roads are roads numbered 5–95 ending with 0 or 5 or having odd numbers 101–129. They generally go across Europe and are usually several thousand kilometres long.
North–south reference roads have numbers that end with the digit 5 from 5 to 9 |
https://en.wikipedia.org/wiki/Wolfram%20Mathematica | Wolfram Mathematica is a software system with built-in libraries for several areas of technical computing that allow machine learning, statistics, symbolic computation, data manipulation, network analysis, time series analysis, NLP, optimization, plotting functions and various types of data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other programming languages. It was conceived by Stephen Wolfram, and is developed by Wolfram Research of Champaign, Illinois. The Wolfram Language is the programming language used in Mathematica. Mathematica 1.0 was released on June 23, 1988 in Champaign, Illinois and Santa Clara, California.
Notebook interface
Mathematica is split into two parts: the kernel and the front end. The kernel interprets expressions (Wolfram Language code) and returns result expressions, which can then be displayed by the front end.
The original front end, designed by Theodore Gray in 1988, consists of a notebook interface and allows the creation and editing of notebook documents that can contain code, plaintext, images, and graphics.
Alternatives to the Mathematica front end include Wolfram Workbench—an Eclipse-based integrated development environment (IDE) that was introduced in 2006. It provides project-based code development tools for Mathematica, including revision management, debugging, profiling, and testing.
There is also a plugin for IntelliJ IDEA-based IDEs to work with Wolfram Language code that in addition to syntax highlighting can analyze and auto-complete local variables and defined functions. The Mathematica Kernel also includes a command line front end.
Other interfaces include JMath, based on GNU Readline and WolframScript which runs self-contained Mathematica programs (with arguments) from the UNIX command line.
The file extension for Mathematica files is .nb and .m for configuration files.
Mathematica is designed to be fully stable and backwards compatible with previous versions.
High-performance computing
Capabilities for high-performance computing were extended with the introduction of packed arrays in version 4 (1999) and sparse matrices (version 5, 2003), and by adopting the GNU Multiple Precision Arithmetic Library to evaluate high-precision arithmetic.
Version 5.2 (2005) added automatic multi-threading when computations are performed on multi-core computers. This release included CPU-specific optimized libraries. In addition Mathematica is supported by third party specialist acceleration hardware such as ClearSpeed.
In 2002, gridMathematica was introduced to allow user level parallel programming on heterogeneous clusters and multiprocessor systems and in 2008 parallel computing technology was included in all Mathematica licenses including support for grid technology such as Windows HPC Server 2008, Microsoft Compute Cluster Server and Sun Grid.
Support for CUDA and OpenCL GPU hardware was added in 2010.
Extensions
As of Version 13, there a |
https://en.wikipedia.org/wiki/NaN | In computing, NaN (), standing for Not a Number, is a particular value of a numeric data type (often a floating-point number) which is undefined or unrepresentable, such as the result of 0/0. Systematic use of NaNs was introduced by the IEEE 754 floating-point standard in 1985, along with the representation of other non-finite quantities such as infinities.
In mathematics, 0/0 is typically undefined and is therefore represented by NaN in computing systems.
The square root of a negative number is not a real number, and is therefore also represented by NaN in compliant computing systems. NaNs may also be used to represent missing values in computations.
Two separate kinds of NaNs are provided, termed quiet NaNs and signaling NaNs. Quiet NaNs are used to propagate errors resulting from invalid operations or values. Signaling NaNs can support advanced features such as mixing numerical and symbolic computation or other extensions to basic floating-point arithmetic.
Floating point
In floating-point calculations, NaN is not the same as infinity, although both are typically handled as special cases in floating-point representations of real numbers as well as in floating-point operations. An invalid operation is also not the same as an arithmetic overflow (which would return an infinity or the largest finite number in magnitude) or an arithmetic underflow (which would return the smallest normal number in magnitude, a subnormal number, or zero).
IEEE 754 NaNs are encoded with the exponent field filled with ones (like infinity values), and some non-zero number in the significand field (to make them distinct from infinity values); this allows the definition of multiple distinct NaN values, depending on which bits are set in the significand field, but also on the value of the leading sign bit (but applications are not required to provide distinct semantics for those distinct NaN values).
For example, an IEEE 754 single precision (32-bit) NaN would be encoded as
where s is the sign (most often ignored in applications) and the x sequence represents a non-zero number (the value zero encodes infinities). In practice, the most significant bit from x is used to determine the type of NaN: "quiet NaN" or "signaling NaN" (see details in Encoding). The remaining bits encode a payload (most often ignored in applications).
Floating-point operations other than ordered comparisons normally propagate a quiet NaN (qNaN). Most floating-point operations on a signaling NaN (sNaN) signal the invalid-operation exception; the default exception action is then the same as for qNaN operands and they produce a qNaN if producing a floating-point result.
The propagation of quiet NaNs through arithmetic operations allows errors to be detected at the end of a sequence of operations without extensive testing during intermediate stages. For example, if one starts with a NaN and adds 1 five times in a row, each addition results in a NaN, but there is no need to check each calcu |
https://en.wikipedia.org/wiki/Spellevator | Spellevator is an educational computer game for the Apple II published by MECC in 1988.
Gameplay
The player controls a dust bunny, which is chased by several vacuum cleaners with different movement patterns. The objective of the level is to grab all the letters and exit through the upper left corner. The player can pass through an unoccupied elevator (some vacuum cleaners use elevators also) by correctly answering a spelling or vocabulary question. Once one completes a level, the player can receive a bonus by correctly unscrambling the letters one grabbed into a word).
Spellevator has a utility on the disk's flipside that let a user create a word list and save it to any ProDOS formatted floppy disk. This way, teachers could customize the game to fit their own particular vocabulary lists.
Legacy
Spellevator was followed by Spellevator Plus for additional platforms.
References
External links
Educational game article at 1up.com
1988 video games
Children's educational video games
Apple II games
Apple II-only games
Video games developed in the United States
The Learning Company games
Multiplayer and single-player video games |
https://en.wikipedia.org/wiki/Grid%20computing | Grid computing is the use of widely distributed computer resources to reach a common goal. A computing grid can be thought of as a distributed system with non-interactive workloads that involve many files. Grid computing is distinguished from conventional high-performance computing systems such as cluster computing in that grid computers have each node set to perform a different task/application. Grid computers also tend to be more heterogeneous and geographically dispersed (thus not physically coupled) than cluster computers. Although a single grid can be dedicated to a particular application, commonly a grid is used for a variety of purposes. Grids are often constructed with general-purpose grid middleware software libraries. Grid sizes can be quite large.
Grids are a form of distributed computing composed of many networked loosely coupled computers acting together to perform large tasks. For certain applications, distributed or grid computing can be seen as a special type of parallel computing that relies on complete computers (with onboard CPUs, storage, power supplies, network interfaces, etc.) connected to a computer network (private or public) by a conventional network interface, such as Ethernet. This is in contrast to the traditional notion of a supercomputer, which has many processors connected by a local high-speed computer bus. This technology has been applied to computationally intensive scientific, mathematical, and academic problems through volunteer computing, and it is used in commercial enterprises for such diverse applications as drug discovery, economic forecasting, seismic analysis, and back office data processing in support for e-commerce and Web services.
Grid computing combines computers from multiple administrative domains to reach a common goal, to solve a single task, and may then disappear just as quickly. The size of a grid may vary from small—confined to a network of computer workstations within a corporation, for example—to large, public collaborations across many companies and networks. "The notion of a confined grid may also be known as an intra-nodes cooperation whereas the notion of a larger, wider grid may thus refer to an inter-nodes cooperation".
Coordinating applications on Grids can be a complex task, especially when coordinating the flow of information across distributed computing resources. Grid workflow systems have been developed as a specialized form of a workflow management system designed specifically to compose and execute a series of computational or data manipulation steps, or a workflow, in the grid context.
Comparison of grids and conventional supercomputers
“Distributed” or “grid” computing in general is a special type of parallel computing that relies on complete computers (with onboard CPUs, storage, power supplies, network interfaces, etc.) connected to a network (private, public or the Internet) by a conventional network interface producing commodity hardware, compared to the lower effi |
https://en.wikipedia.org/wiki/Deep%20Blue%20%28chess%20computer%29 | Deep Blue was a chess-playing expert system run on a unique purpose-built IBM supercomputer. It was the first computer to win a game, and the first to win a match, against a reigning world champion under regular time controls. Development began in 1985 at Carnegie Mellon University under the name ChipTest. It then moved to IBM, where it was first renamed Deep Thought, then again in 1989 to Deep Blue. It first played world champion Garry Kasparov in a six-game match in 1996, where it lost four games to two. It was upgraded in 1997 and in a six-game re-match, it defeated Kasparov by winning two games and drawing three. Deep Blue's victory is considered a milestone in the history of artificial intelligence and has been the subject of several books and films.
History
While a doctoral student at Carnegie Mellon University, Feng-hsiung Hsu began development of a chess-playing supercomputer under the name ChipTest. The machine won the North American Computer Chess Championship in 1987 and Hsu and his team followed up with a successor, Deep Thought, in 1988. After receiving his doctorate in 1989, Hsu and Murray Campbell joined IBM Research to continue their project to build a machine that could defeat a world chess champion. Their colleague Thomas Anantharaman briefly joined them at IBM before leaving for the finance industry and being replaced by programmer Arthur Joseph Hoane. Jerry Brody, a long-time employee of IBM Research, subsequently joined the team in 1990.
After Deep Thought's two-game 1989 loss to Kasparov, IBM held a contest to rename the chess machine: the winning name was "Deep Blue", submitted by Peter Fitzhugh Brown, was a play on IBM's nickname, "Big Blue". After a scaled-down version of Deep Blue played Grandmaster Joel Benjamin, Hsu and Campbell decided that Benjamin was the expert they were looking for to help develop Deep Blue's opening book, so hired him to assist with the preparations for Deep Blue's matches against Garry Kasparov. In 1995, a Deep Blue prototype played in the eighth World Computer Chess Championship, playing Wchess to a draw before ultimately losing to Fritz in round five, despite playing as White.
In 1997, the Chicago Tribune mistakenly reported that Deep Blue had been sold to United Airlines, a confusion based upon its physical resemblance to IBM's mainstream RS6000/SP2 systems.
Today, one of the two racks that made up Deep Blue is held by the National Museum of American History, having previously been displayed in an exhibit about the Information Age, while the other rack was acquired by the Computer History Museum in 1997, and is displayed in the Revolution exhibit's "Artificial Intelligence and Robotics" gallery. Several books were written about Deep Blue, among them Behind Deep Blue: Building the Computer that Defeated the World Chess Champion by Deep Blue developer Feng-hsiung Hsu.
Deep Blue versus Kasparov
Subsequent to its predecessor Deep Thought's 1989 loss to Garry Kasparov, Deep Blue played Kas |
https://en.wikipedia.org/wiki/Hyperlink | In computing, a hyperlink, or simply a link, is a digital reference to data that the user can follow or be guided to by clicking or tapping. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks. The text that is linked from is known as anchor text. A software system that is used for viewing and creating hypertext is a hypertext system, and to create a hyperlink is to hyperlink (or simply to link). A user following hyperlinks is said to navigate or browse the hypertext.
The document containing a hyperlink is known as its source document. For example, in content from Wikipedia or Google Search, many words and terms in the text are hyperlinked to definitions of those terms. Hyperlinks are often used to implement reference mechanisms such as tables of contents, footnotes, bibliographies, indexes, letters, and glossaries.
In some hypertext, hyperlinks can be bidirectional: they can be followed in two directions, so both ends act as anchors and as targets. More complex arrangements exist, such as many-to-many links.
The effect of following a hyperlink may vary with the hypertext system and may sometimes depend on the link itself; for instance, on the World Wide Web most hyperlinks cause the target document to replace the document being displayed, but some are marked to cause the target document to open in a new window (or, perhaps, in a new tab). Another possibility is transclusion, for which the link target is a document fragment that replaces the link anchor within the source document. Not only persons browsing the document may follow hyperlinks. These hyperlinks may also be followed automatically by programs. A program that traverses the hypertext, following each hyperlink and gathering all the retrieved documents is known as a Web spider or crawler.
Links
Inline links
An inline link displays remote content without the need for embedding the content. The remote content may be accessed with or without the user following the link.
An inline link may display a modified version of the content; for instance, instead of an image, a thumbnail, low resolution preview, cropped section, or magnified section may be shown. The full content is then usually available on demand, as is the case with print publishing software e.g., with an external link. This allows for smaller file sizes and quicker response to changes when the full linked content is not needed, as is the case when rearranging a page layout.
Anchor links
An anchor hyperlink (anchor link) is a link bound to a portion of a document, which is often called a fragment. The fragment is generally a portion of text or a heading, though not necessarily. For instance, it may also be a hot area in an image (image map in HTML), a designated, often irregular part of an image.
Fragments are marked with anchors (in any of various ways), which is why a link to a fragment is called an anchor link (that is, a link to an anchor). For example, in |
https://en.wikipedia.org/wiki/Universal%20Disk%20Format | Universal Disk Format (UDF) is an open, vendor-neutral file system for computer data storage for a broad range of media. In practice, it has been most widely used for DVDs and newer optical disc formats, supplanting ISO 9660. Due to its design, it is very well suited to incremental updates on both write-once and re-writable optical media. UDF was developed and maintained by the Optical Storage Technology Association (OSTA).
In engineering terms, Universal Disk Format is a profile of the specification known as ISO/IEC 13346 and ECMA-167.
Usage
Normally, authoring software will master a UDF file system in a batch process and write it to optical media in a single pass. But when packet writing to rewritable media, such as CD-RW, UDF allows files to be created, deleted and changed on-disc just as a general-purpose filesystem would on removable media like floppy disks and flash drives. This is also possible on write-once media, such as CD-R, but in that case the space occupied by the deleted files cannot be reclaimed (and instead becomes inaccessible).
Multi-session mastering is also possible in UDF, though some implementations may be unable to read disks with multiple sessions.
History
The Optical Storage Technology Association standardized the UDF file system to form a common file system for all optical media: both for read-only media and for re-writable optical media. When first standardized, the UDF file system aimed to replace ISO 9660, allowing support for both read-only and writable media. After the release of the first version of UDF, the DVD Consortium adopted it as the official file system for DVD-Video and DVD-Audio.
UDF shares the basic volume descriptor format with ISO 9660. A "UDF Bridge" format is defined since 1.50 so that a disc can also contain a ISO 9660 file system making references to files on the UDF part.
Revisions
Multiple revisions of UDF have been released:
Revision 1.00 (24 October 1995). Original Release.
Revision 1.01 (3 November 1995). Added DVD Appendix and made a few minor changes.
Revision 1.02 (30 August 1996). This format is used by DVD-Video discs.
Revision 1.50 (4 February 1997). Added support for (virtual) rewritability on CD-R/DVD-R media by introducing the VAT structure. Added sparing tables for defect management on rewritable media such as CD-RW, and DVD-RW and DVD+RW. Add UDF bridge.
Revision 2.00 (3 April 1998). Added support for Stream Files and real-time files (for DVD recording) and simplified directory management. VAT support was extended.
Revision 2.01 (15 March 2000) is mainly a bugfix release to UDF 2.00. Many of the UDF standard's ambiguities were resolved in version 2.01.
Revision 2.50 (30 April 2003). Added the Metadata Partition facilitating metadata clustering, easier crash recovery and optional duplication of file system information: All metadata like nodes and directory contents are written on a separate partition which can optionally be mirrored. This format is used by some ver |
https://en.wikipedia.org/wiki/SEX%20%28computing%29 | In computing, the SEX assembly language mnemonic has often been used for the "Sign EXtend" machine instruction found in the Motorola 6809. A computer's or CPU's "sex" can also mean the endianness of the computer architecture used. x86 computers do not have the same "byte sex" as HC11 computers, for example. Functions are sometimes needed for computers of different endianness to communicate with each other over the internet, as protocols often use big endian byte coding by default.
On the RCA 1802 series of microprocessors, the SEX, for "SEt X," instruction is used to designate which of the machine's sixteen 16-bit registers is to be the X (index) register.
SEX in software: rarely used jargon
The TLA SEX has humorously been said to stand for Software EXchange, meaning copying of software. As file sharing has sometimes spread computer viruses, it has been stated that “illicit SEX can transmit viral diseases to your computer.” The involvement of FTP servers' /pub directories in this process has led to the name being explained as a contraction of 'pubic'.
References
Machine code
Computer jargon |
https://en.wikipedia.org/wiki/Ontology%20%28information%20science%29 | In information science, an ontology encompasses a representation, formal naming, and definition of the categories, properties, and relations between the concepts, data, and entities that substantiate one, many, or all domains of discourse. More simply, an ontology is a way of showing the properties of a subject area and how they are related, by defining a set of terms and relational expressions that represent the entities in that subject area. The field which studies ontologies so conceived is sometimes referred to as applied ontology.
Every academic discipline or field creates ontologies to limit complexity and organize data into information and knowledge.
Each uses ontological assumptions to frame explicit theories, research and applications. Improved ontologies may improve problem solving within that domain, interoperability of data systems, and discoverability of data. Translating research papers within every field is a problem made easier when experts from different countries maintain a controlled vocabulary of jargon between each of their languages. For instance, the definition and ontology of economics is a primary concern in Marxist economics, but also in other subfields of economics. An example of economics relying on information science occurs in cases where a simulation or model is intended to enable economic decisions, such as determining what capital assets are at risk and by how much (see risk management).
What ontologies in both information science and philosophy have in common is the attempt to represent entities, including both objects and events, with all their interdependent properties and relations, according to a system of categories. In both fields, there is considerable work on problems of ontology engineering (e.g., Quine and Kripke in philosophy, Sowa and Guarino in information science), and debates concerning to what extent normative ontology is possible (e.g., foundationalism and coherentism in philosophy, BFO and Cyc in artificial intelligence).
Applied ontology is considered by some as a successor to prior work in philosophy. However many current efforts are more concerned with establishing controlled vocabularies of narrow domains than with philosophical first principles, or with questions such as the mode of existence of fixed essences or whether enduring objects (e.g., perdurantism and endurantism) may be ontologically more primary than processes. Artificial intelligence has retained considerable attention regarding applied ontology in subfields like natural language processing within machine translation and knowledge representation, but ontology editors are being used often in a range of fields, including biomedical informatics, industry. Such efforts often use ontology editing tools such as Protégé.
Ontology in Philosophy
Ontology is a branch of philosophy and intersects areas such as metaphysics, epistemology, and philosophy of language, as it considers how knowledge, language, and perception relate to the |
https://en.wikipedia.org/wiki/Programmable%20ROM | A programmable read-only memory (PROM) is a form of digital memory where the contents can be changed once after manufacture of the device. The data is then permanent and cannot be changed. It is one type of read-only memory (ROM). PROMs are used in digital electronic devices to store permanent data, usually low level programs such as firmware or microcode. The key difference from a standard ROM is that the data is written into a ROM during manufacture, while with a PROM the data is programmed into them after manufacture. Thus, ROMs tend to be used only for large production runs with well-verified data. PROMs may be used where the volume required does not make a factory-programmed ROM economical, or during development of a system that may ultimately be converted to ROMs in a mass produced version.
PROMs are manufactured blank and, depending on the technology, can be programmed at wafer, final test, or in system. Blank PROM chips are programmed by plugging them into a device called a PROM programmer. Companies can keep a supply of blank PROMs in stock, and program them at the last minute to avoid large volume commitment. These types of memories are frequently used in microcontrollers, video game consoles, mobile phones, radio-frequency identification (RFID) tags, implantable medical devices, high-definition multimedia interfaces (HDMI) and in many other consumer and automotive electronics products.
History
The PROM was invented in 1956 by Wen Tsing Chow, working for the Arma Division of the American Bosch Arma Corporation in Garden City, New York. The invention was conceived at the request of the United States Air Force to come up with a more flexible and secure way of storing the targeting constants in the Atlas E/F ICBM's airborne digital computer. The patent and associated technology were held under secrecy order for several years while the Atlas E/F was the main operational missile of the United States ICBM force. The term burn, referring to the process of programming a PROM, is also in the original patent, as one of the original implementations was to literally burn the internal whiskers of diodes with a current overload to produce a circuit discontinuity. The first PROM programming machines were also developed by Arma engineers under Chow's direction and were located in Arma's Garden City lab and Air Force Strategic Air Command (SAC) headquarters.
One time programmable memory
OTP (one time programmable) memory is a special type of non-volatile memory (NVM) that permits data to be written to memory only once. Once the memory has been programmed, it retains its value upon loss of power (i.e., is non-volatile). OTP memory is used in applications where reliable and repeatable reading of data is required. Examples include boot code, encryption keys and configuration parameters for analog, sensor or display circuitry. OTP NVM is characterized, over other types of NVM like eFuse or EEPROM, by offering a low power, small area footprint mem |
https://en.wikipedia.org/wiki/Core%20dump | In computing, a core dump, memory dump, crash dump, storage dump, system dump, or ABEND dump consists of the recorded state of the working memory of a computer program at a specific time, generally when the program has crashed or otherwise terminated abnormally. In practice, other key pieces of program state are usually dumped at the same time, including the processor registers, which may include the program counter and stack pointer, memory management information, and other processor and operating system flags and information. A snapshot dump (or snap dump) is a memory dump requested by the computer operator or by the running program, after which the program is able to continue. Core dumps are often used to assist in diagnosing and debugging errors in computer programs.
On many operating systems, a fatal exception in a program automatically triggers a core dump. By extension, the phrase "to dump core" has come to mean in many cases, any fatal error, regardless of whether a record of the program memory exists. The term "core dump", "memory dump", or just "dump" has also become jargon to indicate any output of a large amount of raw data for further examination or other purposes.
Background
The name comes from magnetic-core memory, the principal form of random-access memory from the 1950s to the 1970s. The name has remained long after magnetic-core technology became obsolete.
Earliest core dumps were paper printouts of the contents of memory, typically arranged in columns of octal or hexadecimal numbers (a "hex dump"), sometimes accompanied by their interpretations as machine language instructions, text strings, or decimal or floating-point numbers (cf. disassembler).
As memory sizes increased and post-mortem analysis utilities were developed, dumps were written to magnetic media like tape or disk.
Instead of only displaying the contents of the applicable memory, modern operating systems typically generate a file containing an image of the memory belonging to the crashed process, or the memory images of parts of the address space related to that process, along with other information such as the values of processor registers, program counter, system flags, and other information useful in determining the root cause of the crash. These files can be viewed as text, printed, or analysed with specialised tools such as elfdump on Unix and Unix-like systems, objdump and kdump on Linux, IPCS (Interactive Problem Control System) on IBM z/OS, DVF (Dump Viewing Facility) on IBM z/VM, WinDbg on Microsoft Windows, Valgrind, or other debuggers.
In some operating systems an application or operator may request a snapshot of selected storage blocks, rather than all of the storage used by the application or operating system.
Uses
Core dumps can serve as useful debugging aids in several situations. On early standalone or batch-processing systems, core dumps allowed a user to debug a program without monopolizing the (very expensive) computing facility for |
https://en.wikipedia.org/wiki/Reserved%20word | In a computer language, a reserved word (also known as a reserved identifier) is a word that cannot be used as an identifier, such as the name of a variable, function, or label – it is "reserved from use". This is a syntactic definition, and a reserved word may have no user-defined meaning.
A closely related and often conflated notion is a keyword, which is a word with special meaning in a particular context. This is a semantic definition. By contrast, names in a standard library but not built into a language are not considered reserved words or keywords. The terms "reserved word" and "keyword" are often used interchangeably – one may say that a reserved word is "reserved for use as a keyword" – and formal use varies from language to language. For this article, we distinguish as above.
In general reserved words and keywords need not coincide, but in most modern languages keywords are a subset of reserved words, as this makes parsing easier, since keywords cannot be confused with identifiers. In some languages, like C or Python, reserved words and keywords coincide, while in other languages, like Java, all keywords are reserved words, but some reserved words are not keywords, being reserved for future use. In yet other languages, such as the older languages ALGOL, FORTRAN, and PL/I, there are keywords but no reserved words, with keywords being distinguished from identifiers by other means.
Distinction
The sets of reserved words and keywords in a language often coincide or are almost equal, and the distinction is subtle, so the terms are often used interchangeably. However, in careful use they are distinguished.
Making keywords be reserved words makes lexing easier, as a string of characters will unambiguously be either a keyword or an identifier, without depending on context; thus keywords are usually a subset of reserved words. However, reserved words need not be keywords. For example, in Java, goto is a reserved word, but has no meaning and does not appear in any production rules in the grammar. This is usually done for forward compatibility, so a reserved word may become a keyword in a future version without breaking existing programs.
Conversely, keywords need not be reserved words, with their role understood from context, or they may be distinguished in another manner, such as by stropping. For example, the phrase if = 1 is unambiguous in most grammars, since a control statement of an if clause cannot start with an =, and thus is allowed in some languages, such as FORTRAN. Alternatively, in ALGOL 68, keywords must be stropped – marked in some way to distinguished – in the strict language by listing in bold, and thus are not reserved words. Thus in the strict language the following expression is legal, as the bold keyword if does not conflict with the ordinary identifier if:
if if eq 0 then 1 fi
However, in ALGOL 68 there is also a stropping regime in which keywords are reserved words, an example of how these distinct concepts often coin |
https://en.wikipedia.org/wiki/Alonzo%20Church | Alonzo Church (June 14, 1903 – August 11, 1995) was an American mathematician, computer scientist, logician, and philosopher who made major contributions to mathematical logic and the foundations of theoretical computer science. He is best known for the lambda calculus, the Church–Turing thesis, proving the unsolvability of the Entscheidungsproblem ("decision problem"), the Frege–Church ontology, and the Church–Rosser theorem. He also worked on philosophy of language (see e.g. Church 1970). Alongside his doctoral student Alan Turing, Church is considered one of the founders of computer science.
Life
Alonzo Church was born on June 14, 1903, in Washington, D.C., where his father, Samuel Robbins Church, was a justice of the peace and the judge of the Municipal Court for the District of Columbia. He was the grandson of Alonzo Webster Church (1829-1909), United States Senate Librarian from 1881 to 1901, and great grandson of Alonzo Church, a Professor of Mathematics and Astronomy and 6th President of the University of Georgia. As a young boy, Church was partially blinded by an air gun accident. The family later moved to Virginia after his father lost his position at the university because of failing eyesight. With help from his uncle, also named Alonzo Church, the son attended the private Ridgefield School for Boys in Ridgefield, Connecticut. After graduating from Ridgefield in 1920, Church attended Princeton University, where he was an exceptional student. He published his first paper on Lorentz transformations in 1924 and graduated the same year with a degree in mathematics. He stayed at Princeton for graduate work, earning a Ph.D. in mathematics in three years under Oswald Veblen.
He married Mary Julia Kuczinski in 1925. The couple had three children, Alonzo Jr. (1929), Mary Ann (1933) and Mildred (1938).
After receiving his Ph.D., he taught briefly as an instructor at the University of Chicago. He received a two-year National Research Fellowship that enabled him to attend Harvard University in 1927–1928, and the University of Göttingen and University of Amsterdam the following year.
He taught philosophy and mathematics at Princeton for nearly four decades, from 1929 to 1967. He held the Flint Professorship of Philosophy and Mathematics at the University of California, Los Angeles, 1967–1990. He was a Plenary Speaker at the ICM in 1962 in Stockholm.
He received honorary Doctor of Science degrees from Case Western Reserve University in 1969, Princeton University in 1985, and the University at Buffalo, The State University of New York in 1990 in connection with an international symposium in his honor organized by John Corcoran.
He was elected a Corresponding Fellow of the British Academy (FBA) in 1966, to the American Academy of the Arts and Sciences in 1967, to the National Academy of Sciences in 1978.
A deeply religious person, Church was a lifelong member of the Presbyterian church. He died on August 11, 1995, at the age of 92. He is buried |
https://en.wikipedia.org/wiki/Punched%20tape | Punched tape or perforated paper tape is a form of data storage device that consists of a long strip of paper through which small holes are punched. It was developed from and was subsequently used alongside punched cards, the difference being that the tape is continuous.
Punched cards, and chains of punched cards, were used for control of looms in the 18th century. Use for telegraphy systems started in 1842. Punched tapes were used throughout the 19th and for much of the 20th centuries for programmable looms, teleprinter communication, for input to computers of the 1950s and 1960s, and later as a storage medium for minicomputers and CNC machine tools. During the Second World War, high-speed punched tape systems using optical readout methods were used in code breaking systems. Punched tape was used to transmit data for manufacture of read-only memory chips.
History
Perforated paper tapes were first used by Basile Bouchon in 1725 to control looms. However, the paper tapes were expensive to create, fragile, and difficult to repair. By 1801, Joseph Marie Jacquard had developed machines to create paper tapes by tying punched cards in a sequence for Jacquard looms. The resulting paper tape, also called a "chain of cards", was stronger and simpler both to create and to repair. This led to the concept of communicating data not as a stream of individual cards, but as one "continuous card" (or tape). Paper tapes constructed from punched cards were widely used throughout the 19th century for controlling looms. Many professional embroidery operations still refer to those individuals who create the designs and machine patterns as punchers even though punched cards and paper tape were eventually phased out in the 1990s.
In 1842, a French patent by Claude Seytre described a piano playing device that read data from perforated paper rolls. By 1900, wide perforated music rolls for player pianos were used to distribute popular music to mass markets.
In 1846, Alexander Bain used punched tape to send telegrams. This technology was adopted by Charles Wheatstone in 1857 for the Wheatstone system used for the automated preparation, storage and transmission of data in telegraphy.
In the 1880s, Tolbert Lanston invented the Monotype typesetting system, which consisted of a keyboard and a composition caster. The tape, punched with the keyboard, was later read by the caster, which produced lead type according to the combinations of holes in up to 31 positions. The tape reader used compressed air, which passed through the holes and was directed into certain mechanisms of the caster. The system went into commercial use in 1897 and was in production well into the 1970s, undergoing several changes along the way.
Modern use
In the 21st century, use of punched tape would be very rare, possibly in obsolete military systems or by some hobbyists. In computer numerical control (CNC) machining applications, paper tape is uncommon, but some modern systems still measure the size |
https://en.wikipedia.org/wiki/IBM%20PC%20compatible | IBM PC compatible computers are similar to the original IBM PC, XT, and AT, all from computer giant IBM, that are able to use the same software and expansion cards. Such computers were referred to as PC clones, IBM clones or IBM PC clones. The term "IBM PC compatible" is now a historical description only, since IBM no longer sells personal computers after it sold its personal computer division in 2005 to Chinese technology company Lenovo. The designation "PC", as used in much of personal computer history, has not meant "personal computer" generally, but rather an x86 computer capable of running the same software that a contemporary IBM PC could. The term was initially in contrast to the variety of home computer systems available in the early 1980s, such as the Apple II, TRS-80, and Commodore 64. Later, the term was primarily used in contrast to Apple's Macintosh computers.
These "clones" duplicated almost all the significant features of the original IBM PC architectures. This was facilitated by IBM's choice of commodity hardware components, which were cheap, and by various manufacturers' ability to reverse-engineer the BIOS firmware using a "clean room design" technique. Columbia Data Products built the first clone of the IBM personal computer, the MPC 1600 by a clean-room reverse-engineered implementation of its BIOS. Other rival companies, Corona Data Systems, Eagle Computer, and the Handwell Corporation were threatened with legal action by IBM, who settled with them. Soon after in 1982, Compaq released the very successful Compaq Portable, also with a clean-room reverse-engineered BIOS, and also not challenged legally by IBM.
Some early IBM PC compatibles used the same 8-bit computer bus as the original PC and XT models, but many soon adopted the 16-bit IBM AT bus. It was later renamed the Industry Standard Architecture (ISA) bus, after the Extended Industry Standard Architecture bus open standard for IBM PC compatibles was announced in September 1988 by a consortium of PC clone vendors, led by Compaq and called the Gang of Nine, as an alternative to IBM's proprietary Micro Channel architecture (MCA) introduced in its PS/2 series. Soon after the industry adopted new bus standards in a similar, cooperative way: the VESA Local Bus (VLB), Peripheral Component Interconnect (PCI) and the Accelerated Graphics Port (AGP).
Descendants of the x86 IBM PC compatibles, namely 64-bit computers based on "x86-64/AMD64" chips comprise the majority of desktop computers on the market as of 2021, with the dominant operating system being Microsoft Windows. Interoperability with the bus structure and peripherals of the original PC architecture may be limited or non-existent. Many modern computers are unable to use old software or hardware that depends on portions of the IBM PC compatible architecture which are missing or do not have equivalents in modern computers. For example, computers which boot using Unified Extensible Firmware Interface-based firmware th |
https://en.wikipedia.org/wiki/Arcade%20video%20game | An arcade video game takes player input from its controls, processes it through electrical or computerized components, and displays output to an electronic monitor or similar display. All arcade video games are coin-operated or accept other means of payment, housed in an arcade cabinet, and located in amusement arcades alongside other kinds of arcade games. Until the early 2000s, arcade video games were the largest and most technologically advanced segment of the video game industry.
Early prototypical entries Galaxy Game and Computer Space in 1971 established the principle operations for arcade games, and Atari's Pong in 1972 is recognized as the first successful commercial arcade video game. Improvements in computer technology and gameplay design led to a golden age of arcade video games, the exact dates of which are debated but range from the late 1970s to mid-1980s. This golden age includes Space Invaders, Pac-Man, and Donkey Kong. The arcade industry had a resurgence from the early 1990s to mid-2000s, including Street Fighter II, Mortal Kombat, and Dance Dance Revolution, but ultimately declined in the Western world as competing home video game consoles such as the Sony PlayStation and Microsoft Xbox increased in their graphics and gameplay capability and decreased in cost. Nevertheless, Japan, China, and South Korea retain a strong arcade industry in the present day.
History
Games of skill were popular amusement-park midway attractions from the 19th century on. With the introduction of electricity and coin-operated machines, they facilitated a viable business. When pinball machines with electric lights and displays were introduced in 1933 (but without the user-controller flippers which would not be invented until 1947) these machines were seen as games of luck. Numerous states and cities treated them as amoral playthings for rebellious young people, and banned them into the 1960s and 1970s.
Electro-mechanical games (EM games) appeared in arcades in the mid-20th century. Following Sega's EM game Periscope (1966), the arcade industry experienced a "technological renaissance" driven by "audio-visual" EM novelty games, establishing the arcades as a suitable environment for the introduction of commercial video games in the early 1970s. In the late 1960s, college student Nolan Bushnell had a part-time job at an arcade where he became familiar with EM games such as Chicago Coin's racing game Speedway (1969), watching customers play and helping to maintain the machinery, while learning the game business.
The early mainframe game Spacewar! (1962) inspired the first commercial arcade video game, Computer Space (1971), created by Nolan Bushnell and Ted Dabney and released by Nutting Associates. It was demonstrated at the Amusement & Music Operators Association (AMOA) show in October 1971. Another Spacewar-inspired coin-operated video game, Galaxy Game, was demonstrated at Stanford University in November 1971. Bushnell and Dabney followed their Co |
https://en.wikipedia.org/wiki/Light%20pen | A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with a computer's cathode-ray tube (CRT) display.
It allows the user to point to displayed objects or draw on the screen in a similar way to a touchscreen but with greater positional accuracy. A light pen can work with any CRT-based display, but its ability to be used with LCDs was unclear (though Toshiba and Hitachi displayed a similar idea at the "Display 2006" show in Japan).
A light pen detects changes in brightness of nearby screen pixels when scanned by cathode-ray tube electron beam and communicates the timing of this event to the computer. Since a CRT scans the entire screen one pixel at a time, the computer can keep track of the expected time of scanning various locations on screen by the beam and infer the pen's position from the latest time stamps.
History
The first light pen, at this time still called "light gun", was created around 1951–1955 as part of the Whirlwind I project at MIT, where it was used to select discrete symbols on the screen, and later at the SAGE project, where it was used for tactical real-time-control of a radar-networked airspace.
One of the first more widely deployed uses was in the Situation Display consoles of the AN/FSQ-7 for military airspace surveillance. This is not very surprising, given its relationship with the Whirlwind projects. See Semi-Automatic Ground Environment for more details.
During the 1960s, light pens were common on graphics terminals such as the IBM 2250 and were also available for the IBM 3270 text-only terminal.
Light pen usage was expanded in the early 1980s to music workstations such as the Fairlight CMI and personal computers such as the BBC Micro. IBM PC compatible CGA, HGC and some EGA graphics cards also featured a connector compatible with a light pen, as did early Tandy 1000 computers, the Thomson MO5 computer family, the Amiga, Atari 8-bit, Commodore 8-bit, some MSX computers and Amstrad PCW home computers. For the MSX computers, Sanyo produced a light pen interface cartridge.
Because the user was required to hold their arm in front of the screen for long periods of time (potentially causing "gorilla arm") or to use a desk that tilts the monitor, the light pen fell out of use as a general-purpose input device. Light pen was also perceived as working well only on displays with low persistance, which tend to flicker.
See also
CueCat
Digital pen
Light gun
Pen computing
Stylus (computing)
Notes
References
External links
Computing input devices
History of human–computer interaction
Pointing devices |
https://en.wikipedia.org/wiki/OGG | OGG or ogg may refer to:
Ogg (surname)
Ogg, Texas
Nanny Ogg, a character in the Discworld series of books
Ogg, a multimedia container file format, in computing
Ogg Vorbis, the Vorbis free software/open source audio codec, commonly used with the Ogg container
Kahului Airport's IATA code
Ogg (Cro character), in the Children's Television Workshop animated television show
Ogging, an online computer gaming tactic popularized by the network game Netrek
Oud Gereformeerde Gemeenten, a pietistic Reformed denomination in the Netherlands
Operation Good Guys (OGG), a British TV mockumentary series
Original Gospel Gangstaz, Christian hip hop group
Oxford Geology Group, a British geological society
Oxoguanine glycosylase, a DNA glycosylase enzyme
See also
Oggy (disambiguation) |
https://en.wikipedia.org/wiki/RealMedia | RealMedia is a proprietary multimedia container format created by RealNetworks with the filename extension . RealMedia is generally used in conjunction with RealVideo and RealAudio, while also being used for streaming content over the Internet. Typically these streams are in CBR (constant bitrate), but a container for VBR (variable bitrate) streams named RMVB (RealMedia variable bitrate) has been developed.
Overview
A RealMedia file consists of a series of chunks that can be of several different types:
.RMF: RealMedia file header
PROP: File properties header
MDPR: Media properties header
CONT: Content description header
DATA: Data header
INDX: Index header
Supported audio formats
RealAudio 1.0 (VSELP),
RealAudio 2.0 (LD-CELP), 28_8
AC3,
Cook, cook
ATRAC3,
RealAudio Lossless Format,
LC-AAC,
HE-AAC,
Supported video formats
ClearVideo (from helix spec)
H.263, RV10
H.263, RV13
H.263+, RV20
H.264 precursor, RV30
H.264 precursor, RV40
H.263+ (RV20), RVTR
See also
RealPlayer
Container format
Comparison of video container formats
Comparison of video player software
RealVideo codecs
RealAudio codecs
Helix Community - the free and open source software project from RealNetworks
References
Digital container formats
Media |
https://en.wikipedia.org/wiki/Stoic | Stoic may refer to:
An adherent of Stoicism; one whose moral quality is associated with that school of philosophy
STOIC, a programming language
Stoic (film), a 2009 film by Uwe Boll
Stoic (mixtape), a 2012 mixtape by rapper T-Pain
The Stoic, a 1947 novel by Theodore Dreiser
, an S class submarine of the Royal Navy in World War II
Stoic Studio, an American video game developer
See also
Stoick the Vast, a fictional Viking character (chieftain and Haddock's father) in How To Train Your Dragon books and films |
https://en.wikipedia.org/wiki/Symmetric%20multiprocessing | Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all input and output devices, and are controlled by a single operating system instance that treats all processors equally, reserving none for special purposes. Most multiprocessor systems today use an SMP architecture. In the case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors.
Professor John D. Kubiatowicz considers traditionally SMP systems to contain processors without caches. Culler and Pal-Singh in their 1998 book "Parallel Computer Architecture: A Hardware/Software Approach" mention: "The term SMP is widely used but causes a bit of confusion. [...] The more precise description of what is intended by SMP is a shared memory multiprocessor where the cost of accessing a memory location is the same for all processors; that is, it has uniform access costs when the access actually is to memory. If the location is cached, the access will be faster, but cache access times and memory access times are the same on all processors."
SMP systems are tightly coupled multiprocessor systems with a pool of homogeneous processors running independently of each other. Each processor, executing different programs and working on different sets of data, has the capability of sharing common resources (memory, I/O device, interrupt system and so on) that are connected using a system bus or a crossbar.
Design
SMP systems have centralized shared memory called main memory (MM) operating under a single operating system with two or more homogeneous processors. Usually each processor has an associated private high-speed memory known as cache memory (or cache) to speed up the main memory data access and to reduce the system bus traffic.
Processors may be interconnected using buses, crossbar switches or on-chip mesh networks. The bottleneck in the scalability of SMP using buses or crossbar switches is the bandwidth and power consumption of the interconnect among the various processors, the memory, and the disk arrays. Mesh architectures avoid these bottlenecks, and provide nearly linear scalability to much higher processor counts at the sacrifice of programmability:
Serious programming challenges remain with this kind of architecture because it requires two distinct modes of programming; one for the CPUs themselves and one for the interconnect between the CPUs. A single programming language would have to be able to not only partition the workload, but also comprehend the memory locality, which is severe in a mesh-based architecture.
SMP systems allow any processor to work on any task no matter where the data for that task is located in memory, provided that each task in the system is not in execution on two or more processors at the same time. With proper operating system |
https://en.wikipedia.org/wiki/Communication%20complexity | In theoretical computer science, communication complexity studies the amount of communication required to solve a problem when the input to the problem is distributed among two or more parties. The study of communication complexity was first introduced by Andrew Yao in 1979, while studying the problem of computation distributed among several machines.
The problem is usually stated as follows: two parties (traditionally called Alice and Bob) each receive a (potentially different) -bit string and . The goal is for Alice to compute the value of a certain function, , that depends on both and , with the least amount of communication between them.
While Alice and Bob can always succeed by having Bob send his whole -bit string to Alice (who then computes the function ), the idea here is to find clever ways of calculating with fewer than bits of communication. Note that, unlike in computational complexity theory, communication complexity is not concerned with the amount of computation performed by Alice or Bob, or the size of the memory used, as we generally assume nothing about the computational power of either Alice or Bob.
This abstract problem with two parties (called two-party communication complexity), and its general form with more than two parties, is relevant in many contexts. In VLSI circuit design, for example, one seeks to minimize energy used by decreasing the amount of electric signals passed between the different components during a distributed computation. The problem is also relevant in the study of data structures and in the optimization of computer networks. For surveys of the field, see the textbooks by and .
Formal definition
Let where we assume in the typical case that and . Alice holds an -bit string while Bob holds an -bit string . By communicating to each other one bit at a time (adopting some communication protocol which is agreed upon in advance), Alice and Bob wish to compute the value of such that at least one party knows the value at the end of the communication. At this point the answer can be communicated back so that at the cost of one extra bit, both parties will know the answer. The worst case communication complexity of this communication problem of computing , denoted as , is then defined to be
minimum number of bits exchanged between Alice and Bob in the worst case.
As observed above, for any function , we have .
Using the above definition, it is useful to think of the function as a matrix (called the input matrix or communication matrix) where the rows are indexed by and columns by . The entries of the matrix are . Initially both Alice and Bob have a copy of the entire matrix (assuming the function is known to both parties). Then, the problem of computing the function value can be rephrased as "zeroing-in" on the corresponding matrix entry. This problem can be solved if either Alice or Bob knows both and . At the start of communication, the number of choices for the value of the function on |
https://en.wikipedia.org/wiki/High-speed%20rail | High-speed rail (HSR) is a type of rail transport network utilizing trains that run significantly faster than those of traditional rail, using an integrated system of specialized rolling stock and dedicated tracks. While there is no single standard that applies worldwide, lines built to handle speeds above or upgraded lines in excess of are widely considered to be high-speed.
The first high-speed rail system, the Tōkaidō Shinkansen, began operations in Honshū, Japan, in 1964. Due to the streamlined spitzer-shaped nose cone of the locomotive, the system also became known by its English nickname bullet train. Japan's example was followed by several European countries, initially in France and Germany, and later also in Spain, Italy, and others. Today Europe has an extensive network with numerous international connections. More recent construction since the 21st century has led to China taking a leading role in high-speed rail. , its network accounted for over two-thirds of the world's total.
In addition to these, many other countries have developed high-speed rail infrastructure to connect major cities, including Austria, Belgium, Denmark, Finland, Greece, Indonesia, Japan, Morocco, the Netherlands, Norway, Poland, Portugal, Russia, Saudi Arabia, Serbia, South Korea, Sweden, Switzerland, Taiwan, Turkey, the United Kingdom, the United States, and Uzbekistan. Only in continental Europe and Asia does high-speed rail cross international borders.
High-speed trains mostly operate on standard gauge tracks of continuously welded rail on grade-separated rights of way with large radii. However, certain regions with wider legacy railways, including Russia and Uzbekistan, have sought to develop a high-speed railway network in Russian gauge. There are no narrow gauge high-speed trains. Countries whose legacy network is entirely or mostly of a different gauge than 1435mm – including Japan, Spain and India – have however often opted to build their high speed lines to standard gauge instead of the legacy railway gauge.
High-speed rail is the fastest and most efficient ground-based method of commercial transportation, however due to requirements for large track curves, gentle gradients and grade separated track the construction of high-speed rail is more costly than conventional rail and therefore does not always present an economical advantage over conventional speed rail.
Definitions
Multiple definitions for high-speed rail are in use worldwide.
The European Union Directive 96/48/EC, Annex 1 (see also Trans-European high-speed rail network) defines high-speed rail in terms of:
Infrastructure Track built specially for high-speed travel or specially upgraded for high-speed travel.
Minimum speed limit Minimum speed of on lines specially built for high speed and of about on existing lines which have been specially upgraded. This must apply to at least one section of the line. Rolling stock must be able to reach a speed of at least 200 km/h to be considere |
https://en.wikipedia.org/wiki/Computer%20engineering | Computer engineering (CoE or CpE) is a branch of electronic engineering and computer science that integrates several fields of computer science and electronic engineering required to develop computer hardware and software.
Computer engineering is referred to as computer science and engineering at some universities.
Computer engineers require training in electronic engineering, computer science, hardware-software integration, software design, and software engineering. It uses the techniques and principles of electrical engineering and computer science, and can encompass areas such as artificial intelligence (AI), robotics, computer networks, computer architecture and operating systems. Computer engineers are involved in many hardware and software aspects of computing, from the design of individual microcontrollers, microprocessors, personal computers, and supercomputers, to circuit design. This field of engineering not only focuses on how computer systems themselves work, but also on how to integrate them into the larger picture. Robotics are one of the applications of computer engineering.
Computer engineering usually deals with areas including writing software and firmware for embedded microcontrollers, designing VLSI chips, designing analog sensors, designing mixed signal circuit boards, and designing operating systems. Computer engineers are also suited for robotics research, which relies heavily on using digital systems to control and monitor electrical systems like motors, communications, and sensors.
In many institutions of higher learning, computer engineering students are allowed to choose areas of in-depth study in their junior and senior year because the full breadth of knowledge used in the design and application of computers is beyond the scope of an undergraduate degree. Other institutions may require engineering students to complete one or two years of general engineering before declaring computer engineering as their primary focus.
History
Computer engineering began in 1939 when John Vincent Atanasoff and Clifford Berry began developing the world's first electronic digital computer through physics, mathematics, and electrical engineering. John Vincent Atanasoff was once a physics and mathematics teacher for Iowa State University and Clifford Berry a former graduate under electrical engineering and physics. Together, they created the Atanasoff-Berry computer, also known as the ABC which took five years to complete.
While the original ABC was dismantled and discarded in the 1940s a tribute was made to the late inventors, a replica of the ABC was made in 1997 where it took a team of researchers and engineers four years and $350,000 to build.
The modern personal computer emerged in the 1970s, after several breakthroughs in semiconductor technology. These include the first working transistor by William Shockley, John Bardeen and Walter Brattain at Bell Labs in 1947, planar process by Jean Hoerni, the monolithic integrated circui |
https://en.wikipedia.org/wiki/Hybris%20%28computer%20worm%29 | Hybris (also known as Snow White, Vecna.22528, and Full Moon) is a computer worm believed to have been written by Brazilian virus writer Vecna, member of the computer virus writing group 29A. It first appeared in September 2000 and became more common in January 2001.
Hybris typically comes from an email that appears to be from hahaha@sexyfun.net. Malicious "plug-ins" enhanced Hybris's functionality to include various other e-mail types. Other plugin functionalities include a spinning "wheel of hypnosis."
The name Hybris originates from the text within the virus: "HYBRIS" "(c) Vecna".
External links
F-Secure Description
CERT: Open mail relays used to deliver "Hybris Worm"
The Register: "Vandals behind spread of Hybris worm named"
Email worms |
https://en.wikipedia.org/wiki/Debugger | A debugger or debugging tool is a computer program used to test and debug other programs (the "target" program). The main use of a debugger is to run the target program under controlled conditions that permit the programmer to track its execution and monitor changes in computer resources that may indicate malfunctioning code. Typical debugging facilities include the ability to run or halt the target program at specific points, display the contents of memory, CPU registers or storage devices (such as disk drives), and modify memory or register contents in order to enter selected test data that might be a cause of faulty program execution.
The code to be examined might alternatively be running on an instruction set simulator (ISS), a technique that allows great power in its ability to halt when specific conditions are encountered, but which will typically be somewhat slower than executing the code directly on the appropriate (or the same) processor. Some debuggers offer two modes of operation, full or partial simulation, to limit this impact.
A "trap" occurs when the program cannot normally continue because of a programming bug or invalid data. For example, the program might have tried to use an instruction not available on the current version of the CPU or attempted to access unavailable or protected memory. When the program "traps" or reaches a preset condition, the debugger typically shows the location in the original code if it is a source-level debugger or symbolic debugger, commonly now seen in integrated development environments. If it is a low-level debugger or a machine-language debugger it shows the line in the disassembly (unless it also has online access to the original source code and can display the appropriate section of code from the assembly or compilation).
Features
Typically, debuggers offer a query processor, a symbol resolver, an expression interpreter, and a debug support interface at its top level. Debuggers also offer more sophisticated functions such as running a program step by step (single-stepping or program animation), stopping (breaking) (pausing the program to examine the current state) at some event or specified instruction by means of a breakpoint, and tracking the values of variables. Some debuggers have the ability to modify program state while it is running. It may also be possible to continue execution at a different location in the program to bypass a crash or logical error.
The same functionality which makes a debugger useful for correcting bugs allows it to be used as a software cracking tool to evade copy protection, digital rights management, and other software protection features. It often also makes it useful as a general verification tool, fault coverage, and performance analyzer, especially if instruction path lengths are shown. Early microcomputers with disk-based storage often benefitted from the ability to diagnose and recover corrupted directory or registry data records, to "undelete" files mark |
https://en.wikipedia.org/wiki/JFS%20%28file%20system%29 | Journaled File System (JFS) is a 64-bit journaling file system created by IBM. There are versions for AIX, OS/2, eComStation, ArcaOS and Linux operating systems. The latter is available as free software under the terms of the GNU General Public License (GPL). HP-UX has another, different filesystem named JFS that is actually an OEM version of Veritas Software's VxFS.
In the AIX operating system, two generations of JFS exist, which are called JFS (JFS1) and JFS2 respectively. In other operating systems, such as OS/2 and Linux, only the second generation exists and is called simply JFS. This should not be confused with JFS in AIX that actually refers to JFS1.
History
IBM introduced JFS with the initial release of AIX version 3.1 in February 1990. This file system, now called JFS1 on AIX, was the premier file system for AIX over the following decade and was installed in thousands or millions of customers' AIX systems. Historically, the JFS1 file system is very closely tied to the memory manager of AIX, which is a typical design for a file system supporting only one operating system. JFS was one of the first file systems to support Journaling
In 1995, work began to enhance the file system to be more scalable and to support machines that had more than one processor. Another goal was to have a more portable file system, capable of running on multiple operating systems. After several years of designing, coding, and testing, the new JFS was first shipped in OS/2 Warp Server for eBusiness in April 1999, and then in OS/2 Warp Client in October 2000. In December 1999, a snapshot of the original OS/2 JFS source was granted to the open source community and work was begun to port JFS to Linux. The first stable release of JFS for Linux appeared in June 2001. The JFS for Linux project is maintained by a small group of contributors known as the JFS Core Team. This release of sources also worked to form the basis of a re-port back to OS/2 of the open-source JFS.
In parallel with this effort, some of the JFS development team returned to the AIX Operating System Development Group in 1997 and started to move this new JFS source base to the AIX operating system. In May 2001, a second journaled file system, Enhanced Journaled File System (JFS2), was made available for AIX 5L.
Early in 2008 there was speculation that IBM is no longer interested in maintaining JFS and thus it should not be used in production environments. However, Dave Kleikamp, a member of the IBM Linux Technology Center and JFS Core Team, explained that they still follow changes in the Linux kernel and try to fix potential software bugs. He went on to add that certain distributions expect a larger resource commitment from them and opt not to support the filesystem.
In 2012, TRIM command support for solid-state drives was added to JFS.
Features
JFS supports the following features.
Journal
JFS is a journaling file system. Rather than adding journaling as an add-on feature like in the ext3 fil |
https://en.wikipedia.org/wiki/Personal%20rapid%20transit | Personal Rapid Transit (PRT), also referred to as podcars or guided/railed taxis, is a public transport mode featuring small low-capacity automated vehicles operating on a network of specially built guideways. PRT is a type of automated guideway transit (AGT), a class of system which also includes larger vehicles all the way to small subway systems. In terms of routing, it tends towards personal public transport systems.
PRT vehicles are sized for individual or small group travel, typically carrying no more than three to six passengers per vehicle. Guideways are arranged in a network topology, with all stations located on sidings, and with frequent merge/diverge points. This allows for nonstop, point-to-point travel, bypassing all intermediate stations. The point-to-point service has been compared to a taxi or a horizontal lift (elevator).
Numerous PRT systems have been proposed but most have not been implemented. , only a handful of PRT systems are operational: Morgantown Personal Rapid Transit (the oldest and most extensive), in Morgantown, West Virginia, has been in continuous operation since 1975. Since 2010 a 10-vehicle 2getthere system has operated at Masdar City, UAE, and since 2011 a 21-vehicle Ultra PRT system has run at London Heathrow Airport. A 40-vehicle Vectus system with in-line stations officially opened in Suncheon, South Korea, in April 2014. A PRT system connecting the terminals and parking has been built at the new Chengdu Tianfu International Airport, which opened in 2021.
Overview
Most mass transit systems move people in groups over scheduled routes. This has inherent inefficiencies. For passengers, time is wasted by waiting for the next vehicle to arrive, indirect routes to their destination, stopping for passengers with other destinations, and often confusing or inconsistent schedules. Slowing and accelerating large weights can undermine public transport's benefit to the environment while slowing other traffic.
Personal rapid transit systems attempt to eliminate these wastes by moving small groups nonstop in automated vehicles on fixed tracks. Passengers can ideally board a pod immediately upon arriving at a station, and can – with a sufficiently extensive network of tracks – take relatively direct routes to their destination without stops.
The low weight of PRT's small vehicles allows smaller guideways and support structures than mass transit systems like light rail. The smaller structures translate into lower construction costs, smaller easements, and less visually obtrusive infrastructure.
As it stands, a citywide deployment with many lines and closely spaced stations, as envisioned by proponents, has yet to be constructed. Past projects have failed because of financing, cost overruns, regulatory conflicts, political issues, misapplied technology, and flaws in design, engineering or review.
However, the theory remains active. For example, from 2002 to 2005, the EDICT project, sponsored by the European Union, cond |
https://en.wikipedia.org/wiki/BNF | BNF may refer to:
Science
Backus–Naur form, a formal grammar notation in computer science
Biological nitrogen fixation
British National Formulary, a drug reference manual
β-Naphthoflavone, an organic compound
Organisations
British Nutrition Foundation, a charity
Bibliothèque nationale de France (BnF), the French national library
Political parties
Balawaristan National Front, Pakistan
Belarusian National Front ()
BPF Party, break-away group from 1993 ()
Botswana National Front
Other uses
Big Name Fan, a well-known fan |
https://en.wikipedia.org/wiki/Flash%20memory | Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both use the same cell design, consisting of floating gate MOSFETs. They differ at the circuit level depending on whether the state of the bit line or word lines is pulled high or low: in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate.
Flash memory, a type of floating-gate memory, was invented at Toshiba in 1980 and is based on EEPROM technology. Toshiba began marketing flash memory in 1987. EPROMs had to be erased completely before they could be rewritten. NAND flash memory, however, may be erased, written, and read in blocks (or pages), which generally are much smaller than the entire device. NOR flash memory allows a single machine word to be written to an erased location or read independently. A flash memory device typically consists of one or more flash memory chips (each holding many flash memory cells), along with a separate flash memory controller chip.
The NAND type is found mainly in memory cards, USB flash drives, solid-state drives (those produced since 2009), feature phones, smartphones, and similar products, for general storage and transfer of data. NAND or NOR flash memory is also often used to store configuration data in digital products, a task previously made possible by EEPROM or battery-powered static RAM. A key disadvantage of flash memory is that it can endure only a relatively small number of write cycles in a specific block.
Flash memory is used in computers, PDAs, digital audio players, digital cameras, mobile phones, synthesizers, video games, scientific instrumentation, industrial robotics, and medical electronics. Flash memory has a fast read access time but it is not as fast as static RAM or ROM. In portable devices, it is preferred to use flash memory because of its mechanical shock resistance since mechanical drives are more prone to mechanical damage.
Because erase cycles are slow, the large block sizes used in flash memory erasing give it a significant speed advantage over non-flash EEPROM when writing large amounts of data. flash memory costs greatly less than byte-programmable EEPROM and had become the dominant memory type wherever a system required a significant amount of non-volatile solid-state storage. EEPROMs, however, are still used in applications that require only small amounts of storage, as in serial presence detect.
Flash memory packages can use die stacking with through-silicon vias and several dozen layers of 3D TLC NAND cells (per die) simultaneously to achieve capacities of up to 1 tebibyte per package using 16 stacked dies and an integrated flash controller as a separate die inside the package.
History
Background
The origins of flash memory can be traced back to the development of |
https://en.wikipedia.org/wiki/EEPROM | EEPROM (also called E2PROM) stands for electrically erasable programmable read-only memory and is a type of non-volatile memory used in computers, usually integrated in microcontrollers such as smart cards and remote keyless systems, or as a separate chip device to store relatively small amounts of data by allowing individual bytes to be erased and reprogrammed.
EEPROMs are organized as arrays of floating-gate transistors. EEPROMs can be programmed and erased in-circuit, by applying special programming signals. Originally, EEPROMs were limited to single-byte operations, which made them slower, but modern EEPROMs allow multi-byte page operations. An EEPROM has a limited life for erasing and reprogramming, now reaching a million operations in modern EEPROMs. In an EEPROM that is frequently reprogrammed, the life of the EEPROM is an important design consideration.
Flash memory is a type of EEPROM designed for high speed and high density, at the expense of large erase blocks (typically 512 bytes or larger) and limited number of write cycles (often 10,000). There is no clear boundary dividing the two, but the term "EEPROM" is generally used to describe non-volatile memory with small erase blocks (as small as one byte) and a long lifetime (typically 1,000,000 cycles). Many past microcontrollers included both (flash memory for the firmware and a small EEPROM for parameters), though the trend with modern microcontrollers is to emulate EEPROM using flash.
As of 2020, flash memory costs much less than byte-programmable EEPROM and is the dominant memory type wherever a system requires a significant amount of non-volatile solid-state storage. EEPROMs, however, are still used on applications that only require small amounts of storage, like in serial presence detect.
History
In the early 1970s, some studies, inventions, and development for electrically re-programmable non-volatile memories were performed by various companies and organizations.
In 1971, the earliest research report was presented at the 3rd Conference on Solid State Devices, Tokyo in Japan by Yasuo Tarui, Yutaka Hayashi, and Kiyoko Nagai at Electrotechnical Laboratory; a Japanese national research institute.
They fabricated an EEPROM device in 1972, and continued this study for more than 10 years.
These papers have been repeatedly cited by later papers and patents.
One of their research studies includes MONOS (metal-oxide-nitride-oxide-semiconductor) technology,
which used Renesas Electronics' flash memory integrated in single-chip microcontrollers.
In 1972, a type of electrically re-programmable non-volatile memory was invented by Fujio Masuoka at Toshiba, who is also known as the inventor of flash memory.
Most of the major semiconductor manufactures, such as
Toshiba,
Sanyo (later, ON Semiconductor),
IBM,
Intel,
NEC (later, Renesas Electronics),
Philips (later, NXP Semiconductors),
Siemens (later, Infineon Technologies),
Honeywell (later, Atmel),
Texas Instruments,
studied, invented, and |
https://en.wikipedia.org/wiki/Chmod | In Unix and Unix-like operating systems, is the command and system call used to change the access permissions and the special mode flags (the setuid, setgid, and sticky flags) of file system objects (files and directories). Collectively these were originally called its modes, and the name was chosen as an abbreviation of change mode.
History
A command first appeared in AT&T UNIX version 1, along with the system call.
As systems grew in number and types of users, access-control lists were added to many file systems in addition to these most basic modes to increase flexibility.
The version of bundled in GNU coreutils was written by David MacKenzie and Jim Meyering. The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities. The command has also been ported to the IBM i operating system.
Command syntax
Throughout this section, ser refers to the owner of the file, as a reminder that the symbolic form of the command uses "u".
chmod [options] mode[,mode] file1 [file2 ...]
Usually implemented options include:
Recursive, i.e. include objects in subdirectories.
verbose, show objects changed (unchanged objects are not shown).
If a symbolic link is specified, the target object is affected. File modes directly associated with symbolic links themselves are typically not used.
To view the file mode, the or commands may be used:
$ ls -l findPhoneNumbers.sh
-rwxr-xr-- 1 dgerman staff 823 Dec 16 15:03 findPhoneNumbers.sh
$ stat -c %a findPhoneNumbers.sh
754
The , , and specify the read, write, and execute access (the first character of the display denotes the object type; a hyphen represents a plain file). The script can be read, written to, and executed by the user ; read and executed by members of the group; and only read by any other users.
The main parts of the permissions:
For example:
Each group of three characters define permissions for each class:
the three leftmost characters, , define permissions for the User class (i.e. the file owner).
the middle three characters, , define permissions for the Group class (i.e. the group owning the file)
the rightmost three characters, , define permissions for the Others class. In this example, users who are not the owner of the file and who are not members of the Group (and, thus, are in the Others class) have no permission to access the file.
Numerical permissions
The numerical format accepts up to four digits. The three rightmost digits define permissions for the file user, the group, and others. The optional leading digit, when 4 digits are given, specifies the special , , and flags. Each digit of the three rightmost digits represents a binary value, which controls the "read", "write" and "execute" permissions respectively. A value of 1 means a class is allowed that action, while a 0 means it is disallowed.
For example, would allow:
"read" (4), "write" (2), and "execute" ( |
https://en.wikipedia.org/wiki/Dot%20matrix%20printing | Dot matrix printing, sometimes called impact matrix printing, is a computer printing process in which ink is applied to a surface using a relatively low-resolution dot matrix for layout. Dot matrix printers are a type of impact printer that prints using a fixed number of pins or wires and typically use a print head that moves back and forth or in an up-and-down motion on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper. They were also known as serial dot matrix printers. Unlike typewriters or line printers that use a similar print mechanism, a dot matrix printer can print arbitrary patterns and not just specific characters.
The perceived quality of dot matrix printers depends on the vertical and horizontal resolution and the ability of the printer to overlap adjacent dots. 9-pin and 24-pin are common; this specifies the number of pins in a specific vertically aligned space. With 24-pin printers, the horizontal movement can slightly overlap dots, producing visually superior output (near letter quality or NLQ), usually at the cost of speed.
Dot matrix printing is typically distinguished from non-impact methods, such as inkjet, thermal, or laser printing, which also use a bitmap to represent the printed work. These other technologies can support higher dot resolutions and print more quickly, with less noise. Unlike other technologies, impact printers can print on multi-part forms, allowing multiple copies to be made simultaneously, often on paper of different colors. It can also employ endless printing using continuous paper fanfolded with perforations for each page to be easily torn from each other.
History
In 1925, Rudolf Hell invented the Hellschreiber, an early facsimile-like dot matrixbased teletypewriter device, patented in 1929.
Between 1952 and 1954 Fritz Karl Preikschat filed five patent applications for his teletype writer 7 stylus 35 dot matrix aka PKT printer, a dot matrix teletypewriter built between 1954 and 1956 in Germany. Like the earlier Hellschreiber, it still used electromechanical means of coding and decoding, but it used a start-stop method (asynchronous transmission) rather than synchronous transmission for communication. In 1956, while he was employed at Telefonbau und Normalzeit GmbH (TuN, later called Tenovis), the device was offered to the Deutsche Bundespost (German Post Office), which did not show interest.
When Preikschat emigrated to the US in 1957 he sold the rights to utilize the applications in any countries (except for the USA) to TuN. The prototype was also shown to General Mills in 1957. An improved transistorized design became the basis for a portable dot matrix facsimile machine, which was prototyped and evaluated for military use by Boeing around 1966–1967.
IBM marketed its first dot matrix printer in 1957, the same year that the dye-sublimation printer entered the market.
In 1968, the Japanese manufacturer OKI introduced its first serial impact dot matrix printer ( |
https://en.wikipedia.org/wiki/Line%20matrix%20printer | A line matrix printer is a computer printer that is a compromise between a line printer and a dot matrix printer. A line matrix printer prints page-wide lines of dots, building up a line of text by printing lines of dots.
Applications
Line matrix printers are used for high-speed printing applications They are used to produce invoices, bank statements, product shipment and transportation documentation as well as product compliance labels.
Line matrix printers can print text, bar codes and graphics.
When implemented as impact printers, they can be the least expensive to operate per page.
How it works
Dot matrix printers are widely used because of their low cost per page. Dot matrix printers are divided into two main groups: serial dot matrix printers and line matrix printers.
A serial dot matrix printer has a print head that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter. However, unlike a typewriter or daisy wheel printer, letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.
Both line matrix and serial dot matrix printers use pins to strike against the inked ribbon, making dots on the paper and forming the desired characters. The difference is that a line matrix printer uses a hammer bank (or print-shuttle) instead of print head. This print-shuttle has hammers instead of print wires, and these hammers are arranged in a horizontal row instead in vertical column. The hammer bank uses the same technology as the permanent magnet print head with the small difference that instead of print wires the print-shuttle has hammers.
The permanent magnetic field holds the hammer spring in stressed, ready to strike position. The driver sends electric current to hammer coil, which creates an electromagnetic field opposing the permanent magnetic field. When the two fields equalize, the energy stored in the spring is released to strike the hammer against the ribbon and print a dot on the paper.
During the printing process the print-shuttle vibrates in horizontal direction with high speed while the print hammers are fired selectively. Each hammer prints a series of dots in horizontal direction for one pass of the shuttle, then paper advances at one step and the shuttle prints the following row of dots.
References
Line printers |
https://en.wikipedia.org/wiki/Page%20printer | A page printer is a computer printer which processes and prints a whole page at a time, as opposed to printers which print one line or character at a time such as line printers and dot-matrix printers. Page printers are often all incorrectly termed “laser printers”—although virtually all laser printers are page printers, other page printing technologies also exist
Components
The components of a page printer are:
A print engine, "the unit within a printer that does the actual printing." For example, in a laser printer this would consist of the laser and drum and the mechanical paper feeds.
Memory to process input and build up the image of a page. The printer may have its own memory or may use the host computer's memory.
A page description language (PDL), with commands which tell the printer how to format the page. Popular PDLs are PCL (Printer Command Language) from Hewlett-Packard, PostScript from Adobe Systems and PostScript clones, and Windows’ Graphics Device Interface (GDI).
A raster image processor (RIP), i.e. a processor which constructs the bitmap image of the page. Sometimes, this processing is done by the host computer. In other cases printers may have imbedded processors to perform this task.
A printer driver, a program (device driver) which converts the computer's information about the page into the actual PDL. Printer drivers may be included with the operating system, be distributed with the printer on CDs or DVDs, or be downloaded from the printer manufacturer's home page or from independent web sites.
A connection (interface) to the host computer. Many printers communicate by Wi-Fi. Other popular interfaces are USB and Ethernet. Many older printers also have a parallel (Centronics) interface. High-end printers often have a channel interface for direct connection to a mainframe computer.
Page printing technologies
There are several page printing technologies, for example:
Laser printers, in which a laser beam draws the page image on charged drum which collects charged toner and transfers the image to paper.
LED printers, which use light-emitting diodes instead of a laser beam, but are otherwise very similar to laser printers.
Melted wax (“phaser”) printers, where solid ink is heated to the melting point and is applied on the print medium where it immediately solidifies.
Dye-sublimation printers, where a solid ink (dye) is converted to a gaseous state (sublimation) and applied on the print medium, where it immediately solidifies.
Properties
Resolution, 600 or 1200 dpi (dots per inch) is common in most modern page printers, often with resolution enhancement or anti-aliasing to smooth uneven lines. Higher resolutions are common. Before about 1992, the year Hewlett-Packard made the LaserJet 4, built around a Canon engine, most page printers had only 300 dpi, which made visible jagged lines and relatively poor image quality.
Engine speed. In 1984 Canon introduced the first “small”—— laser printers which could sit on a (sturdy) de |
https://en.wikipedia.org/wiki/Inkjet%20printing | Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensive consumer models to expensive professional machines. By 2019, laser printers outsold inkjet printers by nearly a 2:1 ratio, 9.6% vs 5.1% of all computer peripherals. As of 2023, sublimation printers have outsold inkjet printers by nearly a 2:1 ratio, accounting for 9.6% of all computer peripherals, compared to 5.1% for inkjet printers.
The concept of inkjet printing originated in the 20th century, and the technology was first extensively developed in the early 1950s. While working at Canon in Japan, Ichiro Endo suggested the idea for a "Bubble jet" printer, while around the same time Jon Vaught at HP was developing a similar idea. In the late 1970s, inkjet printers that could reproduce digital images generated by computers were developed, mainly by Epson, Hewlett-Packard (HP) and Canon. In the worldwide consumer market, four manufacturers account for the majority of inkjet printer sales: Canon, HP, Epson and Brother.
In 1982, Robert Howard came up with the idea to produce a small color printing system that used piezos to spit drops of ink. He formed the company, R.H. (Robert Howard) Research (named Howtek, Inc. in Feb 1984), and developed the revolutionary technology that led to the Pixelmaster color printer with solid ink using Thermojet technology. This technology consists of a tubular single nozzle acoustical wave drop generator invented originally by Steven Zoltan in 1972 with a glass nozzle and improved by the Howtek inkjet engineer in 1984 with a Tefzel molded nozzle to remove unwanted fluid frequencies.
The emerging ink jet material deposition market also uses inkjet technologies, typically printheads using piezoelectric crystals, to deposit materials directly on substrates.
The technology has been extended and the 'ink' can now also comprise solder paste in PCB assembly, or living cells, for creating biosensors and for tissue engineering.
Images produced on inkjet printers are sometimes sold under trade names such as Digigraph, Iris prints, giclée, and Cromalin. Inkjet-printed fine art reproductions are commonly sold under such trade names to imply a higher-quality product and avoid association with everyday printing.
Methods
Fluid surface tension naturally pulls a stream into droplets. Optimal drop sizes of require an inkjet nozzle size of about . Fluids with surface tension may be water based, wax or oil based and even melted metal alloys. Most drops can be electrically charged. There are two main technologies in use in contemporary inkjet printers: continuous (CIJ) and drop-on-demand (DOD). Continuous inkjet means the flow is pressurized and in a continuous stream. Drop-on-demand means the fluid is expelled from the jet nozzle one drop at a time. This can be done with a mechanical mea |
https://en.wikipedia.org/wiki/Stored%20energy%20printer | A stored energy printer is a computer printer that uses the energy stored in a spring or magnetic field to push a hammer through a ribbon to print a dot. As compared to dot matrix printers that print a single column of dots at a time, this printer generally creates an entire line of dots at a time. Therefore, it is also known as a line matrix printer. This technology produces premium impact printers that print for millions to billions of dots per hammer. The advantage of this technology is that it has the lowest known cost of ownership: ink is transferred by conventional typewriter-style ribbons.
Technology and use
The most common printer to use this technology was the line-matrix printer made by Printronix and its licensees. In this type, the hammers are arranged as a "hammerbank"; a type of comb that oscillate horizontally to produce a line of dots.
A character matrix printer has also been produced. In this printer, the hammers are machined from an oval of magnetically permeable stainless steel, and the hammer-tips form vertical rows.
The original technology, patented by Printronix in 1974, has the top of a stiff leaf spring held back by a magnetic pole-piece. A tungsten carbide hammer is brazed to the center-top of the leaf spring. When it produces a dot, a coil (electromagnet) wrapped around the pole-piece neutralizes the magnetic field. The leaf spring snaps the hammer away from the pole-piece, pushing the hammer out against a ribbon and placing an image of a dot onto the paper.
Recent designs have performed complex optimizations in the magnetic circuit, and eliminated unwanted resonances in the spring. The result was a near-doubling of speed. Other improvements include the use of electrical discharge machining to produce complex, three-dimensional hammers that trade-off the magnetic circuit, mechanical resonances, and printing speed.
Normal wear usually occurs when the spring rubs against the pole-piece as it returns. This causes the pole-piece to wear, eventually requiring the pole pieces to be reground and recertified.
Hexavalent chrome plating on the pole-piece, combined with careful design, more than doubles speeds and improves life-span. It produces approximately a billion impressions per hammer.
Computer peripherals
Computer printers
Impact printers |
https://en.wikipedia.org/wiki/Transform%20coding | Transform coding is a type of data compression for "natural" data like audio signals or photographic images. The transformation is typically lossless (perfectly reversible) on its own but is used to enable better (more targeted) quantization, which then results in a lower quality copy of the original input (lossy compression).
In transform coding, knowledge of the application is used to choose information to discard, thereby lowering its bandwidth. The remaining information can then be compressed via a variety of methods. When the output is decoded, the result may not be identical to the original input, but is expected to be close enough for the purpose of the application.
Colour television
NTSC
One of the most successful transform encoding system is typically not referred to as such—the example being NTSC color television. After an extensive series of studies in the 1950s, Alda Bedford showed that the human eye has high resolution only for black and white, somewhat less for "mid-range" colors like yellows and greens, and much less for colors on the end of the spectrum, reds and blues.
Using this knowledge allowed RCA to develop a system in which they discarded most of the blue signal after it comes from the camera, keeping most of the green and only some of the red; this is chroma subsampling in the YIQ color space.
The result is a signal with considerably less content, one that would fit within existing 6 MHz black-and-white signals as a phase modulated differential signal. The average TV displays the equivalent of 350 pixels on a line, but the TV signal contains enough information for only about 50 pixels of blue and perhaps 150 of red. This is not apparent to the viewer in most cases, as the eye makes little use of the "missing" information anyway.
PAL and SECAM
The PAL and SECAM systems use nearly identical or very similar methods to transmit colour. In any case both systems are subsampled.
Digital
The term is much more commonly used in digital media and digital signal processing. The most widely used transform coding technique in this regard is the discrete cosine transform (DCT), proposed by Nasir Ahmed in 1972, and presented by Ahmed with T. Natarajan and K. R. Rao in 1974. This DCT, in the context of the family of discrete cosine transforms, is the DCT-II. It is the basis for the common JPEG image compression standard, which examines small blocks of the image and transforms them to the frequency domain for more efficient quantization (lossy) and data compression. In video coding, the H.26x and MPEG standards modify this DCT image compression technique across frames in a motion image using motion compensation, further reducing the size compared to a series of JPEGs.
In audio coding, MPEG audio compression analyzes the transformed data according to a psychoacoustic model that describes the human ear's sensitivity to parts of the signal, similar to the TV model. MP3 uses a hybrid coding algorithm, combining the modified discrete c |
https://en.wikipedia.org/wiki/DASD%20%28disambiguation%29 | DASD may refer to:
Direct-access storage device, a computer storage device
Education
DeForest Area School District
Downingtown Area School District
DuBois Area School District |
https://en.wikipedia.org/wiki/List%20of%20computing%20and%20IT%20abbreviations | This is a list of computing and IT acronyms, initialisms and abbreviations.
0–9
1GL—First-Generation Programming Language
1NF—First Normal Form
10B2—10BASE-2
10B5—10BASE-5
10B-F—10BASE-F
10B-FB—10BASE-FB
10B-FL—10BASE-FL
10B-FP—10BASE-FP
10B-T—10BASE-T
100B-FX—100BASE-FX
100B-TX—100BASE-TX
100BVG—100BASE-VG
286—Intel 80286 processor
2B1Q—2 Binary 1 Quaternary
2FA—Two-factor authentication
2GL—Second-Generation Programming Language
2NF—Second Normal Form
3GL—Third-Generation Programming Language
3GPP—3rd Generation Partnership Project – 3G comms
3GPP2—3rd Generation Partnership Project 2
3NF—Third Normal Form
386—Intel 80386 processor
486—Intel 80486 processor
4B5BLF—4-bit 5-bit Local Fiber
4GL—Fourth-Generation Programming Language
4NF—Fourth Normal Form
5GL—Fifth-Generation Programming Language
5NF—Fifth Normal Form
6NF—Sixth Normal Form
8B10BLF—8-bit 10-bit Local Fiber
802.11—Wireless LAN
A
AAA—Authentication Authorization, Accounting
AABB—Axis Aligned Bounding Box
AAC—Advanced Audio Coding
AAL—ATM Adaptation Layer
AALC—ATM Adaptation Layer Connection
AARP—AppleTalk Address Resolution Protocol
ABAC—Attribute-Based Access Control
ABCL—Actor-Based Concurrent Language
ABI—Application Binary Interface
ABM—Asynchronous Balanced Mode
ABR—Area Border Router
ABR—Auto Baud-Rate detection
ABR—Available Bitrate
ABR—Average Bitrate
ABR—Adaptive Bitrate (Streaming)
AC—Acoustic Coupler
AC—Alternating Current
ACD—Automatic Call Distributor
ACE—Advanced Computing Environment
ACID—Atomicity Consistency Isolation Durability
ACK—ACKnowledgement
ACK—Amsterdam Compiler Kit
ACL—Access Control List
ACL—Active Current Loop
ACM—Association for Computing Machinery
ACME—Automated Classification of Medical Entities
ACP—Airline Control Program
ACPI—Advanced Configuration and Power Interface
ACR—Allowed Cell Rate
ACR—Attenuation to Crosstalk Ratio
AD—Active Directory
AD—Administrative Domain
ADC—Analog-to-Digital Converter
ADC—Apple Display Connector
ADB—Apple Desktop Bus
ADCCP—Advanced Data Communications Control Procedures
ADO—ActiveX Data Objects
ADSL—Asymmetric Digital Subscriber Line
ADT—Abstract Data Type
AE—Adaptive Equalizer
AES—Advanced Encryption Standard
AF—Anisotropic Filtering
AFP—Apple Filing Protocol
AGP—Accelerated Graphics Port
AH—Active Hub
AI—Artificial Intelligence
AIX—Advanced Interactive eXecutive
Ajax—Asynchronous JavaScript and XML
AL—Active Link
AL—Access List
ALAC—Apple Lossless Audio Codec
ALGOL—Algorithmic Language
ALSA—Advanced Linux Sound Architecture
ALU—Arithmetic and Logical Unit
AM—Access Method
AM—Active Matrix
AMOLED—Active-Matrix Organic Light-Emitting Diode
AM—Active Monitor
AM—Allied Mastercomputer
AM—Amplitude Modulation
AMD—Advanced Micro Devices
AMQP—Advanced Message Queuing Protocol
AMR—Audio Modem Riser
ANN—Artificial Neural Network
ANSI—American National Standards Institute
ANT—Another Neat Tool
AoE—ATA over Ethernet
AOP—Aspec |
https://en.wikipedia.org/wiki/Paleoclimatology | Paleoclimatology (British spelling, palaeoclimatology) is the scientific study of climates predating the invention of meteorological instruments, when no direct measurement data were available. As instrumental records only span a tiny part of Earth's history, the reconstruction of ancient climate is important to understand natural variation and the evolution of the current climate.
Paleoclimatology uses a variety of proxy methods from Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils. Combined with techniques to date the proxies, the paleoclimate records are used to determine the past states of Earth's atmosphere.
The scientific field of paleoclimatology came to maturity in the 20th century. Notable periods studied by paleoclimatologists are the frequent glaciations that Earth has undergone, rapid cooling events like the Younger Dryas, and the rapid warming during the Paleocene–Eocene Thermal Maximum. Studies of past changes in the environment and biodiversity often reflect on the current situation, specifically the impact of climate on mass extinctions and biotic recovery and current global warming.
History
Notions of a changing climate probably evolved in ancient Egypt, Mesopotamia, the Indus Valley and China, where prolonged periods of droughts and floods were experienced. In the seventeenth century, Robert Hooke postulated that fossils of giant turtles found in Dorset could only be explained by a once warmer climate, which he thought could be explained by a shift in Earth's axis. Fossils were in that time often explained as a consequence of a Biblical flood. Systematic observations of sunspots started by amateur astronomer Heinrich Schwabe in the early 19th century, starting a discussion of the Sun's influence on Earth's climate.
The scientific study field of paleoclimatology began to further take shape in the early 19th century, when discoveries about glaciations and natural changes in Earth's past climate helped to understand the greenhouse effect. It was only in the 20th century that paleoclimatology became a unified scientific field. Before, different aspects of Earth's climate history were studied by a variety of disciplines. At the end of the 20th century, the empirical research into Earth's ancient climates started to be combined with computer models of increasing complexity. A new objective also developed in this period: finding ancient analog climates that could provide information about current climate change.
Reconstructing ancient climates
Paleoclimatologists employ a wide variety of techniques to deduce ancient climates. The techniques used depend on which variable has to be reconstructed (temperature, precipitation or something else) and on how long ago the climate of interest occurred. For instance, the deep marine record, the source of most isotopic data, exists only on oceanic plates, which are eventually subducted: t |
https://en.wikipedia.org/wiki/Pipeline | A pipeline is a system of pipes for long-distance transportation of a liquid or gas, typically to a market area for consumption. The latest data from 2014 gives a total of slightly less than of pipeline in 120 countries around the world. The United States had 65%, Russia had 8%, and Canada had 3%, thus 76% of all pipeline were in these three countries.
Pipeline and Gas Journal'''s worldwide survey figures indicate that of pipelines are planned and under construction. Of these, represent projects in the planning and design phase; reflect pipelines in various stages of construction. Liquids and gases are transported in pipelines, and any chemically stable substance can be sent through a pipeline.
Pipelines exist for the transport of crude and refined petroleum, fuels – such as oil, natural gas and biofuels – and other fluids including sewage, slurry, water, beer, hot water or steam for shorter distances. Pipelines are useful for transporting water for drinking or irrigation over long distances when it needs to move over hills, or where canals or channels are poor choices due to considerations of evaporation, pollution, or environmental impact. Oil pipelines are made from steel or plastic tubes which are usually buried. The oil is moved through the pipelines by pump stations along the pipeline. Natural gas (and similar gaseous fuels) are pressurized into liquids known as natural gas liquids (NGLs). Natural gas pipelines are constructed of carbon steel. Hydrogen pipeline transport is the transportation of hydrogen through a pipe. Pipelines are one of the safest ways of transporting materials as compared to road or rail, and hence in war, pipelines are often the target of military attacks.
Oil and natural gas
It is well documented when the first crude oil pipeline was built. Credit for the development of pipeline transport belongs indisputably to the Oil Transport Association, which first constructed a wrought iron pipeline over a track from an oil field in Pennsylvania to a railroad station in Oil Creek, in the 1860s. Pipelines are generally the most economical way to transport large quantities of oil, refined oil products or natural gas over land. For example, in 2014, pipeline transport of crude oil cost about $5 per barrel, while rail transport cost about $10 to $15 per barrel. Trucking has even higher costs due to the additional labor required; employment on completed pipelines represents only "1% of that of the trucking industry.".
In the United States, 70% of crude oil and petroleum products are shipped by pipeline. (23% are by ship, 4% by truck, and 3% by rail) In Canada for natural gas and petroleum products, 97% are shipped by pipeline.
Natural gas (and similar gaseous fuels) are lightly pressurized into liquids known as Natural Gas Liquids (NGLs). Small NGL processing facilities can be located in oil fields so the butane and propane liquid under light pressure of , can be shipped by rail, truck or pipeline. Propane can be used |
https://en.wikipedia.org/wiki/SoftICE | SoftICE is a kernel mode debugger for DOS and Windows up to Windows XP. It is designed to run underneath Windows, so that the operating system is unaware of its presence. Unlike an application debugger, SoftICE is capable of suspending all operations in Windows when instructed. Because of its low-level capabilities, SoftICE is also popular as a software cracking tool.
Microsoft offers two kernel-mode debuggers, WinDbg and KD, without charges. However, the full capabilities of WinDbg and KD are available only when two interlinked computers are used. SoftICE, therefore, is an exceptionally useful tool for difficult driver related development. The last released version was for Windows XP.
Older versions exist for DOS and compatible operating systems. SoftICE was originally produced by the company NuMega, and was subsequently acquired by Compuware in 1997, which in turn sold the property to Micro Focus in 2009. Currently, Micro Focus owns the source code and patents, but is not actively maintaining SoftICE.
Naming
"Soft" refers to software, and "ICE" is an allusion to in-circuit emulator.
History
The original SoftICE for DOS was written in 1987 by NuMega founders Frank Grossman and Jim Moskun. The program, written in 80386 assembly language, played the role of an operating system and ran software in virtual 8086 mode. It sold for $386.
SoftICE/W (for Windows) was developed in the 1990s, and was instrumental in the Writing of "Undocumented Windows", by Andrew Schulman, David Maxey and Matt Pietrek. SoftICE/W was derived from an earlier, lesser known product, SoftICE for NetWare (32-bit protected mode). One of the key advantages it had over Microsoft's debuggers is that it enabled single machine debugging, rather than requiring a second machine to be connected over a serial port.
The principal developers of SoftICE were Dom Basile ('Mr. SoftICE'), Tom Guinther (Kitchen Sink, Symbol Engine), Gerald Ryckman (Video drivers and Kitchen Sink), Ray Hsu (Video drivers for Windows 95), and Dan Babcock (SoftICE/NT 3.1/3.5: Universal video driver, symbol engine), with contributions by a variety of NuMega developers including Frank Grossman, Jim Moskun and Matt Pietrek.
In 1998, the codebase for SoftICE/95 was ported to run on the Windows NT platform.
Newer versions of SoftICE patch deep into Microsoft Windows. As such, old versions of SoftICE are rarely compatible with new versions of Windows. Compuware therefore offered SoftICE as a subscription so that it could be kept up to date and in sync with the latest Microsoft Windows version.
SoftICE was previously offered as part of Compuware's DriverStudio package, but was discontinued in April 2006.
Termination
As of April 3, 2006, the DriverStudio product family has been discontinued because of "a variety of technical and business issues as well as general market conditions". Maintenance support was offered until March 31, 2007.
Anti-SoftICE measures
Software vendors have put in place a wide range of |
https://en.wikipedia.org/wiki/DNIX | DNIX (original spelling: D-Nix) is a discontinued Unix-like real-time operating system from the Swedish company Dataindustrier AB (DIAB). A version named ABCenix was developed for the ABC 1600 computer from Luxor. Daisy Systems also had a system named Daisy DNIX on some of their computer-aided design (CAD) workstations. It was unrelated to DIAB's product.
History
Inception at DIAB in Sweden
Dataindustrier AB (literal translation: computer industries shareholding company) was started in 1970 by Lars Karlsson as a single-board computer manufacture in Sundsvall, Sweden, producing a Zilog Z80-based computer named Data Board 4680. In 1978, DIAB started to work with the Swedish television company Luxor AB to produce the home and office computer series ABC 80 and ABC 800.
In 1983 DIAB independently developed the first Unix-compatible machine, DIAB DS90 based on the Motorola 68000 CPU. D-NIX here made its appearance, based on a UNIX System V license from AT&T Corporation. DIAB was however an industrial control system (automation) company, and needed a real-time operating system, so the company replaced the AT&T-supplied UNIX kernel with their own in-house developed, yet compatible real-time variant. This kernel was inspired by a Z80 kernel named OS.8 created for Monroe Systems division of Litton Industries.
Over time, the company also replaced several of the UNIX standard userspace tools with their own implementations, to the point where no code was derived from UNIX, and their machines could be deployed independently of any AT&T UNIX license. Two years later and in cooperation with Luxor, a computer called ABC 1600 was developed for the office market, while in parallel, DIAB continue to produce enhanced versions of the DS90 computer using newer versions of the Motorola CPUs such as Motorola 68010, 68020, 68030 and eventually 68040. In 1990 DIAB was acquired by Groupe Bull who continued to produce and support the DS machines under the brand name DIAB, with names such as DIAB 2320, DIAB 2340 etc., still running DIABs version of DNIX.
Derivative at ISC Systems Corporation
ISC Systems Corporation (ISC) purchased the right to use DNIX in the late 1980s for use in its line of Motorola 68k-based banking computers. (ISC was later bought by Olivetti, and was in turn resold to Wang, which was then bought by Getronics. This corporate entity, most often referred to as 'ISC', has answered to a bewildering array of names over the years.) This code branch was the SVR2 compatible version, and received extensive modification and development at their hands. Notable features of this operating system were its support of demand paging, diskless workstations, multiprocessing, asynchronous input/output (I/O), the ability to mount processes (handlers) on directories in the file system, and message passing. Its real-time support consisted largely of internal event-driven queues rather than list search mechanisms (no 'thundering herd'), static process priorities in two |
https://en.wikipedia.org/wiki/Network%20File%20System | Network File System (NFS) is a distributed file system protocol originally developed by Sun Microsystems (Sun) in 1984, allowing a user on a client computer to access files over a computer network much like local storage is accessed. NFS, like many other protocols, builds on the Open Network Computing Remote Procedure Call (ONC RPC) system. NFS is an open IETF standard defined in a Request for Comments (RFC), allowing anyone to implement the protocol.
Versions and variations
Sun used version 1 only for in-house experimental purposes. When the development team added substantial changes to NFS version 1 and released it outside of Sun, they decided to release the new version as v2, so that version interoperation and RPC version fallback could be tested.
NFSv2
Version 2 of the protocol (defined in RFC 1094, March 1989) originally operated only over User Datagram Protocol (UDP). Its designers meant to keep the server side stateless, with locking (for example) implemented outside of the core protocol. People involved in the creation of NFS version 2 include Russel Sandberg, Bob Lyon, Bill Joy, Steve Kleiman, and others.
The Virtual File System interface allows a modular implementation, reflected in a simple protocol. By February 1986, implementations were demonstrated for operating systems such as System V release 2, DOS, and VAX/VMS using Eunice.
NFSv2 only allows the first 2 GB of a file to be read due to 32-bit limitations.
NFSv3
Version 3 (RFC 1813, June 1995) added:
support for 64-bit file sizes and offsets, to handle files larger than 2 gigabytes (GB);
support for asynchronous writes on the server, to improve write performance;
additional file attributes in many replies, to avoid the need to re-fetch them;
a READDIRPLUS operation, to get file handles and attributes along with file names when scanning a directory;
assorted other improvements.
The first NFS Version 3 proposal within Sun Microsystems was created not long after the release of NFS Version 2. The principal motivation was an attempt to mitigate the performance issue of the synchronous write operation in NFS Version 2. By July 1992, implementation practice had solved many shortcomings of NFS Version 2, leaving only lack of large file support (64-bit file sizes and offsets) a pressing issue. This became an acute pain point for Digital Equipment Corporation with the introduction of a 64-bit version of Ultrix to support their newly released 64-bit RISC processor, the Alpha 21064. At the time of introduction of Version 3, vendor support for TCP as a transport-layer protocol began increasing. While several vendors had already added support for NFS Version 2 with TCP as a transport, Sun Microsystems added support for TCP as a transport for NFS at the same time it added support for Version 3. Using TCP as a transport made using NFS over a WAN more feasible, and allowed the use of larger read and write transfer sizes beyond the 8 KB limit imposed by User Datagram Protocol.
WebNFS
|
https://en.wikipedia.org/wiki/Translation%20memory | A translation memory (TM) is a database that stores "segments", which can be sentences, paragraphs or sentence-like units (headings, titles or elements in a list) that have previously been translated, in order to aid human translators. The translation memory stores the source text and its corresponding translation in language pairs called “translation units”. Individual words are handled by terminology bases and are not within the domain of TM.
Software programs that use translation memories are sometimes known as translation memory managers (TMM) or translation memory systems (TM systems, not to be confused with a translation management system (TMS), which is another type of software focused on managing process of translation).
Translation memories are typically used in conjunction with a dedicated computer-assisted translation (CAT) tool, word processing program, terminology management systems, multilingual dictionary, or even raw machine translation output.
Research indicates that many companies producing multilingual documentation are using translation memory systems. In a survey of language professionals in 2006, 82.5% out of 874 replies confirmed the use of a TM. Usage of TM correlated with text type characterised by technical terms and simple sentence structure (technical, to a lesser degree marketing and financial), computing skills, and repetitiveness of content.
Using translation memories
The program breaks the source text (the text to be translated) into segments, looks for matches between segments and the source half of previously translated source-target pairs stored in a translation memory, and presents such matching pairs as translation full and/or partial matches. The translator can accept a match, replace it with a fresh translation, or modify it to match the source. In the last two cases, the new or modified translation goes into the database.
Some translation memory systems search for 100% matches only, that is to say that they can only retrieve segments of text that match entries in the database exactly, while others employ fuzzy matching algorithms to retrieve similar segments, which are presented to the translator with differences flagged. It is important to note that typical translation memory systems only search for text in the source segment.
The flexibility and robustness of the matching algorithm largely determine the performance of the translation memory, although for some applications the recall rate of exact matches can be high enough to justify the 100%-match approach.
Segments where no match is found will have to be translated by the translator manually. These newly translated segments are stored in the database where they can be used for future translations as well as repetitions of that segment in the current text.
Translation memories work best on texts which are highly repetitive, such as technical manuals. They are also helpful for translating incremental changes in a previously translated document, c |
https://en.wikipedia.org/wiki/AutoLISP | AutoLISP is a dialect of the programming language Lisp built specifically for use with the full version of AutoCAD and its derivatives, which include AutoCAD Map 3D, AutoCAD Architecture and AutoCAD Mechanical. Neither the application programming interface (API) nor the interpreter to execute AutoLISP code is included in the AutoCAD LT product line (up to Release 2023, AutoCAD LT 2024 includes AutoLISP). A subset of AutoLISP functions is included in the browser-based AutoCAD web app.
Features
AutoLISP is a small, dynamically scoped, dynamically typed Lisp language dialect with garbage collection, immutable list structure, and settable symbols, lacking in such regular Lisp features as macro system, records definition facilities, arrays, functions with variable number of arguments or let bindings. Aside from the core language, most of the primitive functions are for geometry, accessing AutoCAD's internal DWG database, or manipulation of graphical entities in AutoCAD. The properties of these graphical entities are revealed to AutoLISP as association lists in which values are paired with AutoCAD group codes that indicate properties such as definitional points, radii, colors, layers, linetypes, etc. AutoCAD loads AutoLISP code from .LSP files.
AutoLISP code can interact with the user through AutoCAD's graphical editor by use of primitive functions that allow the user to pick points, choose objects on screen, and input numbers and other data. AutoLisp also has a built-in graphical user interface (GUI) mini- or domain-specific language (DSL), the Dialog Control Language, for creating modal dialog boxes with automated layout, within AutoCAD.
History
AutoLISP was derived from an early version of XLISP, which was created by David Betz. The language was introduced in AutoCAD Version 2.18 in January 1986, and continued to be enhanced in successive releases up to release 13 in February 1995. After that, its development was neglected by Autodesk in favor of more fashionable development environments like Visual Basic for Applications (VBA), .NET Framework, and ObjectARX. However, it has remained AutoCAD's main user customizing language.
Vital-LISP, a considerably enhanced version of AutoLISP including an integrated development environment (IDE), debugger, compiler, and ActiveX support, was developed and sold by third-party developer Basis Software. Vital LISP was a superset of the existing AutoLISP language that added VBA-like access to the AutoCAD object model, reactors (event handling for AutoCAD objects), general ActiveX support, and some other general Lisp functions. Autodesk purchased this, renamed it Visual LISP, and briefly sold it as an add-on to AutoCAD release 14 released in May 1997. It was incorporated into AutoCAD 2000 released in March 1999, as a replacement for AutoLISP. Since then, Autodesk has ceased major enhancements to Visual LISP and focused more effort on VBA and .NET, and C++. , Autodesk ended support for VBA versions before 7.1, as p |
https://en.wikipedia.org/wiki/Geostatistics | Geostatistics is a branch of statistics focusing on spatial or spatiotemporal datasets. Developed originally to predict probability distributions of ore grades for mining operations, it is currently applied in diverse disciplines including petroleum geology, hydrogeology, hydrology, meteorology, oceanography, geochemistry, geometallurgy, geography, forestry, environmental control, landscape ecology, soil science, and agriculture (esp. in precision farming). Geostatistics is applied in varied branches of geography, particularly those involving the spread of diseases (epidemiology), the practice of commerce and military planning (logistics), and the development of efficient spatial networks. Geostatistical algorithms are incorporated in many places, including geographic information systems (GIS).
Background
Geostatistics is intimately related to interpolation methods, but extends far beyond simple interpolation problems. Geostatistical techniques rely on statistical models that are based on random function (or random variable) theory to model the uncertainty associated with spatial estimation and simulation.
A number of simpler interpolation methods/algorithms, such as inverse distance weighting, bilinear interpolation and nearest-neighbor interpolation, were already well known before geostatistics. Geostatistics goes beyond the interpolation problem by considering the studied phenomenon at unknown locations as a set of correlated random variables.
Let be the value of the variable of interest at a certain location . This value is unknown (e.g. temperature, rainfall, piezometric level, geological facies, etc.). Although there exists a value at location that could be measured, geostatistics considers this value as random since it was not measured, or has not been measured yet. However, the randomness of is not complete, but defined by a cumulative distribution function (CDF) that depends on certain information that is known about the value :
Typically, if the value of is known at locations close to (or in the neighborhood of ) one can constrain the CDF of by this neighborhood: if a high spatial continuity is assumed, can only have values similar to the ones found in the neighborhood. Conversely, in the absence of spatial continuity can take any value. The spatial continuity of the random variables is described by a model of spatial continuity that can be either a parametric function in the case of variogram-based geostatistics, or have a non-parametric form when using other methods such as multiple-point simulation or pseudo-genetic techniques.
By applying a single spatial model on an entire domain, one makes the assumption that is a stationary process. It means that the same statistical properties are applicable on the entire domain. Several geostatistical methods provide ways of relaxing this stationarity assumption.
In this framework, one can distinguish two modeling goals:
Estimating the value for , typically by the expectation, |
https://en.wikipedia.org/wiki/Category%205%20cable | Category 5 cable (Cat 5) is a twisted pair cable for computer networks. Since 2001, the variant commonly in use is the Category 5e specification (Cat 5e). The cable standard provides performance of up to 100 MHz and is suitable for most varieties of Ethernet over twisted pair up to 2.5GBASE-T but more commonly runs at (Gigabit Ethernet) speeds. Cat 5 is also used to carry other signals such as telephone and video.
This cable is commonly connected using punch-down blocks and modular connectors. Most Category 5 cables are unshielded, relying on the balanced line twisted pair design and differential signaling for noise suppression.
Standards
Category 5 is currently defined in ISO/IEC 11801, IEC 61156 and EN 50173, though it was originally defined in ANSI/TIA/EIA-568-A (with clarification in TSB-95). These documents specify performance characteristics and test requirements for frequencies up to 100 MHz.
The cable is available in both stranded and solid conductor forms. The stranded form is more flexible and withstands more bending without breaking. Patch cables are stranded. Permanent wiring used in structured cabling is solid. The category and type of cable can be identified by the printing on the jacket.
The Category 5 specification requires conductors to be pure copper. There has seen a rise in counterfeit cables, especially of the copper-clad aluminum (CCA) variety. This has exposed the manufacturers and installers of such fake cable to legal liabilities.
Variants and comparisons
The Category 5e specification improves upon the Category 5 specification by further mitigating crosstalk. The bandwidth (100 MHz) and physical construction are the same between the two, and most Cat 5 cables actually happen to meet Cat 5e specifications even though they are not certified as such. Category 5 was deprecated in 2001 and superseded by the Category 5e specification.
The Category 6 specification improves upon the Category 5e specification by extending frequency response and further reducing crosstalk. The improved performance of Cat 6 provides 250 MHz bandwidth. Category 6A cable provides 500 MHz bandwidth. Both variants are backward compatible with Category 5 and 5e cables.
Termination
Cable types, connector types and cabling topologies are defined by ANSI/TIA-568. Category 5 cable is nearly always terminated with 8P8C modular connectors (often referred to incorrectly as RJ45 connectors). The cable is terminated in either the T568A scheme or the T568B scheme. The two schemes work equally well and may be mixed in an installation so long as the same scheme is used on both ends of each cable.
Applications
Category 5 cable is used in structured cabling for computer networks such as Ethernet over twisted pair. The cable standard prescribes performance parameters for frequencies up to and is suitable for , (Fast Ethernet), (Gigabit Ethernet), and . and Ethernet connections require two wire pairs. 1000BASE-T and faster Ethernet connections require |
https://en.wikipedia.org/wiki/Enhanced%20Interior%20Gateway%20Routing%20Protocol | Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration. The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers. In 2013, Cisco permitted other vendors to freely implement a limited version of EIGRP with some of its associated features such as High Availability (HA), while withholding other EIGRP features such as EIGRP stub, needed for DMVPN and large-scale campus deployment. Information needed for implementation was published with informational status as in 2016, which did not advance to Internet Standards Track level, and allowed Cisco to retain control of the EIGRP protocol.
EIGRP is used on a router to share routes with other routers within the same autonomous system. Unlike other well known routing protocols, such as RIP, EIGRP only sends incremental updates, reducing the workload on the router and the amount of data that needs to be transmitted.
EIGRP replaced the Interior Gateway Routing Protocol (IGRP) in 1993. One of the major reasons for this was the change to classless IPv4 addresses in the Internet Protocol, which IGRP could not support.
Overview
Almost all routers contain a routing table that contains rules by which traffic is forwarded in a network. If the router does not contain a valid path to the destination, the traffic is discarded. EIGRP is a dynamic routing protocol by which routers automatically share route information. This eases the workload on a network administrator who does not have to configure changes to the routing table manually.
In addition to the routing table, EIGRP uses the following tables to store information:
Neighbor Table: The neighbor table keeps a record of the IP addresses of routers that have a direct physical connection with this router. Routers that are connected to this router indirectly, through another router, are not recorded in this table as they are not considered neighbors.
Topology Table: The topology table stores routes that it has learned from neighbor routing tables. Unlike a routing table, the topology table does not store all routes, but only routes that have been determined by EIGRP. The topology table also records the metrics for each of the listed EIGRP routes, the feasible successor and the successors. Routes in the topology table are marked as "passive" or "active". Passive indicates that EIGRP has determined the path for the specific route and has finished processing. Active indicates that EIGRP is still trying to calculate the best path for the specific route. Routes in the topology table are not usable by the router until they are inserted into the routing table. The topology table is never used by the router to forward traffic. Routes in the topology table will not be inserted into the routing table if they are active, are a feasible successor, or have a higher administrative distance than an equivale |
https://en.wikipedia.org/wiki/The%20Powerpuff%20Girls | The Powerpuff Girls is an American superhero animated television series created by animator Craig McCracken and produced by Hanna-Barbera (later Cartoon Network Studios) for Cartoon Network and distributed by Warner Bros. Domestic Television Distribution. The show centers on Blossom, Bubbles, and Buttercup, three kindergarten-aged girls with superpowers. The girls all live in the fictional city of Townsville with their father and creator, a scientist named Professor Utonium, and are frequently called upon by the city's mayor to help fight nearby criminals and other enemies using their powers.
While attending his second year at CalArts in 1992, series creator Craig McCracken created a short film, Whoopass Stew!, about a trio of child superheroes called the Whoopass Girls, which was only shown at festivals. Following a name change to Powerpuff Girls, McCracken submitted his student film to Cartoon Network, who aired the series' refined pilot in its animation showcase program World Premiere Toons on February 20, 1995, along with its follow-up, "Crime 101", which aired on January 28, 1996. Network executives gave McCracken the greenlight for a full series, which debuted as a Cartoon Cartoon on November 18, 1998.
The Powerpuff Girls aired on Cartoon Network for six seasons, three specials, and a feature film, with the final episode airing on March 25, 2005. A total of 78 episodes were aired in addition to two shorts, a Christmas special, the film, a tenth anniversary special, and a special episode using CGI technology. Various spin-off media include an anime, three CD soundtracks, a home video collection, comic books, a series of video games, a 2016 reboot series, and an upcoming second reboot, as well as various licensed merchandise. The series has been nominated for six Emmy Awards, nine Annie Awards, and a Kids' Choice Award during its run.
Premise
The show revolves around the adventures of three kindergarten-aged girls with an array of various superpowers: Blossom (pink), Bubbles (blue), and Buttercup (green). The plot of an episode is usually some humorous variation of standard superhero and tokusatsu shows, with the girls using their powers to defend their town from villains and giant monsters. In addition, the girls have to deal with the normal issues that young children face, such as sibling rivalries, loose teeth, personal hygiene, going to school, bed wetting, or dependence on a security blanket. Episodes often contain hidden references to older pop culture (especially noticeable in the episode "Meet the Beat Alls", which is a homage to the Beatles). The cartoon always tries to keep different ideas within each episode with some small tributes and parodies thrown in.
The show is set mainly in the city of Townsville, USA. Townsville is depicted as a major American city, with a cityscape consisting of several major skyscrapers. In his review of The Powerpuff Girls Movie, movie critic Bob Longino of The Atlanta Journal-Constitution said, "t |
https://en.wikipedia.org/wiki/Microsoft%20Bob | Microsoft Bob was a Microsoft software product intended to provide a more user-friendly interface for the Windows 3.1x, Windows 95 and Windows NT operating systems, supplanting the Windows Program Manager. The program was released on March 11, 1995 and discontinued in early 1996. Microsoft Bob presented screens showing a house, with rooms that the user could visit containing familiar objects corresponding to computer applications, such as a desk with pen and paper and a checkbook. Clicking on the pen and paper would open the system's word processor.
A cartoon dog named Rover and other cartoon characters provided guidance using speech balloons.
Upon release, Microsoft Bob was criticized in the media and did not gain wide acceptance with users, which resulted in its discontinuation. Its legacy would be observed in future Microsoft products, notably the use of virtual assistants. The Rover character later reappeared as a Windows XP search companion.
History
Microsoft Bob was released in March 1995 (before Windows 95 was released), although it had been widely publicized under the codename Utopia. The project leader for Bob was Karen Fries, a Microsoft researcher. The design was based on research by professors Clifford Nass and Byron Reeves of Stanford University. Melinda Gates, wife of Bill Gates, was the marketing manager for the product. Microsoft originally purchased the domain name bob.com from Boston-area techie Bob Antia, but later traded it to Bob Kerstein for the windows2000.com domain name.
Applications
Microsoft Bob includes various office-suite programs such as a finance application and a word processor. The user interface was designed to simplify the navigational experience for novice computer users.
Similar to early graphical shells like Jane, the main interface is portrayed as the inside of a house, with different rooms corresponding to common real-world room styles such as a kitchen or family room. Each room contains decorations and furniture, as well as icons that represent applications. The user may also fully customize the entire house and has full control over each room's decoration. The user may add, remove or reposition all objects. The user can also add or remove rooms and change the destinations of each door. The program offers multiple themes for room designs and decorations, such as contemporary and postmodern.
The applications built into Microsoft Bob are represented by matching decorations. For example, clicking on a clock opens the calendar, while a pen and paper represent the word processor. The user can also add shortcuts to applications on the computer. These shortcuts display the icon inside various styles of decorations, such as boxes and picture frames.
Bob includes the ability to install new applications, but because of the failure of the product, only a single add-on application package, Microsoft Great Greetings, was released.
Released just as the Internet was beginning to become popular, Bob offered an e |
https://en.wikipedia.org/wiki/James%20Gosling | James Gosling (born 19 May 1955) is a Canadian computer scientist, best known as the founder and lead designer behind the Java programming language.
Gosling was elected a member of the National Academy of Engineering in 2004 for the conception and development of the architecture for the Java programming language and for contributions to window systems.
Early life
Gosling attended William Aberhart High School in Calgary, Alberta. While in high school, he wrote some of the software to analyze data from the ISIS 2 satellite, working for the University of Calgary physics department. He received a Bachelor of Science from the University of Calgary and his M.A. and Ph.D. from Carnegie Mellon University, all in computer science. He wrote a version of Emacs called Gosling Emacs (Gosmacs) while working toward his doctorate. He built a multi-processor version of Unix for a 16-way computer system while at Carnegie Mellon University, before joining Sun Microsystems. He also developed several compilers and mail systems there.
Gosling has two children, Katie and Kelsey, who are half siblings from Gosling's two marriages.
Career & contributions
Gosling was with Sun Microsystems between 1984 and 2010 (26 years). At Sun he invented an early Unix windowing system called NeWS, which became a lesser-used alternative to the still used X Window System, because Sun did not give it an open source license.
He is known as the father of the Java programming language. He got the idea for the Java VM while writing a program to port software from a PERQ by translating Perq Q-Code to VAX assembler and emulating the hardware. He is generally credited with having invented the Java programming language in 1994.
He created the original design of Java and implemented the language's original compiler and virtual machine. Gosling traces the origins of the approach to his early graduate student days, when he created a p-code virtual machine for the lab's DEC VAX computer, so that his professor could run programs written in UCSD Pascal. In the work leading to Java at Sun, he saw that architecture-neutral execution for widely distributed programs could be achieved by implementing a similar philosophy: always program for the same virtual machine.
Another contribution of Gosling's was co-writing the "bundle" program, known as "shar", a utility thoroughly detailed in Brian Kernighan and Rob Pike's book The Unix Programming Environment.
He left Sun Microsystems on April 2, 2010, after it was acquired by the Oracle Corporation, citing reductions in pay, status, and decision-making ability, along with change of role and ethical challenges. He has since taken a very critical stance towards Oracle in interviews, noting that "during the integration meetings between Sun and Oracle, where we were being grilled about the patent situation between Sun and Google, we could see the Oracle lawyer's eyes sparkle." He clarified his position during the Oracle v. Google trial over Android: "While |
https://en.wikipedia.org/wiki/Dave%20Cutler | David Neil Cutler Sr. (born March 13, 1942) is an American software engineer. He developed several computer operating systems, namely Microsoft's Windows NT, and Digital Equipment Corporation's RSX-11M, VAXELN, and VMS.
Personal history
Cutler was born in Lansing, Michigan and grew up in DeWitt, Michigan. After graduating from Olivet College, Michigan, in 1965, he went to work for DuPont.
Cutler holds at least 20 patents, and is affiliate faculty in the Computer Science Department at the University of Washington.
Cutler is an avid auto racing driver. He competed in the Atlantic Championship from 1996 to 2002, scoring a career best of 8th on the Milwaukee Mile in 2000.
Cutler was elected a member of the National Academy of Engineering in 1994 for the design and engineering of commercially successful operating systems.
Cutler is a member of Adelphic Alpha Pi Fraternity at Olivet College, Michigan.
DuPont (1965 to 1971)
Cutler's first exposure to computers came when he was tasked to perform a computer simulations model for one of DuPont's customers using IBM's GPSS-3 language on an IBM model 7044. This work led to an interest in how computers and their operating systems worked.
Digital Equipment Corporation (1971 to 1988)
Cutler left DuPont to pursue his interest in computer systems, beginning with Digital Equipment Corporation in 1971. He worked at Digital's headquarters in Maynard, Massachusetts.
RSX-11M
VMS
In April 1975, DEC began a hardware project, code-named Star, to design a 32-bit virtual address extension to its PDP-11. In June 1975, Cutler, together with Dick Hustvedt and Peter Lipman, were appointed the technical project leaders for the software project, code-named Starlet, to develop a totally new operating system for the Star family of processors. These two projects were tightly integrated from the beginning.
The three technical leaders of the Starlet project together with three technical leaders of the Star project formed the "Blue Ribbon Committee" at DEC that produced the fifth design evolution for the programs. The design featured simplifications to the memory management and process scheduling schemes of the earlier proposals and the architecture was accepted. The Star and Starlet projects culminated in the development of the VAX-11/780 superminicomputer and the VAX/VMS operating system, respectively.
PRISM and MICA projects
DEC began working on a new CPU using reduced instruction set computer (RISC) design principles in 1986. Cutler, who was working in DEC's DECwest facility in Bellevue, Washington, was selected to head PRISM, a project to develop the company's RISC machine. Its operating system, code named MICA, was to embody the next generation of design principles and have a compatibility layer for Unix and VMS. The RISC machine was to be based on emitter-coupled logic (ECL) technology, and was one of three ECL projects DEC was undertaking at the time.
Funding the research and development of multiple ECL projec |
https://en.wikipedia.org/wiki/Informix | Informix is a product family within IBM's Information Management division that is centered on several relational database management system (RDBMS) and Multi-model database offerings. The Informix products were originally developed by Informix Corporation, whose Informix Software subsidiary was acquired by IBM in 2001.
In April 2017, IBM delegated active development and support to HCL Technologies for 15 years, with a number of IBM employees working on Informix also moving to HCL. As part of this arrangement IBM will continue to market and sell it as IBM Informix to their customers, with HCLTech able to market and sell it as HCL Informix.
The current version of Informix is 14.10 and forms the basis of several product editions with variation in capacity and functionality. The Informix database has been used in many high transaction rate OLTP applications in the retail, finance, energy and utilities, manufacturing and transportation sectors. More recently the server has been enhanced to improve its support for data warehouse workloads. Through extensions, Informix supports data types that are not a part of the SQL standard.
On 24th Jul, 2020 HCL announced OneDB Database Server V1.0.0.0 as a multi-model (relational, object-relational, and dimensional) DBMS based on Informix. On August 19, 2021 HCL released OneDB 2.0 as a cloud native, multi-cloud, Kubernetes-orchestrated offering.
On December 29, 2021 Actian (formerly Ingres Corporation) became fully owned by HCL America. Actian remained a separate entity, now acting as the Data, Analytics and Insights division of HCLSoftware. It's expected the Informix portfolio will be transferred from HCL to Actian, with HCL Informix and OneDB already available for download at Actian's Electronic Software Distribution (ESD) portal.
Key products
As of 2023, the current version of both IBM and HCL Informix is 14.10. The major enhancements made over previous releases were adding built-in index compression, integration of JSON collections with support for MongoDB JSON drivers into the server, and an enhancement permitting database objects to be partitioned across multiple servers in a cluster or grid (aka sharding). Queries can optionally return data from the locally connected server instance or from an entire grid with the same SQL.
Informix version 14.10 introduced support for partial indexing where only a subset of the rows in a table are indexed and for multi-valued key indexes which support indexing the elements within multi-valued data types such as LIST, SET, MULTISET, and BSON array fields.
Heterogeneous clusters are fully supported, and there are several deployment options that are available, including some that provide very high levels of data redundancy and fault tolerance. This feature is marketed by IBM as Informix Flexible Grid.
Regarding HCL Informix 14.10, key highlights include:
Functional parity with IBM Informix 14.10 for on-premises deployment
Replacement of FlexNet license manag |
https://en.wikipedia.org/wiki/Transcontinental%20railroad | A transcontinental railroad or transcontinental railway is contiguous railroad trackage, that crosses a continental land mass and has terminals at different oceans or continental borders. Such networks can be via the tracks of either a single railroad or over those owned or controlled by multiple railway companies along a continuous route. Although Europe is crisscrossed by railways, the railroads within Europe are usually not considered transcontinental, with the possible exception of the historic Orient Express.
Transcontinental railroads helped open up unpopulated interior regions of continents to exploration and settlement that would not otherwise have been feasible. In many cases they also formed the backbones of cross-country passenger and freight transportation networks. Many of them continue to have an important role in freight transportation and some like the Trans-Siberian Railway even have passenger trains going from one end to the other.
North America
United States
A transcontinental railroad in the United States is any continuous rail line connecting a location on the U.S. Pacific coast with one or more of the railroads of the nation's eastern trunk line rail systems operating between the Missouri or Mississippi Rivers and the U.S. Atlantic coast. The first concrete plan for a transcontinental railroad in the United States was presented to Congress by Asa Whitney in 1845.
A series of transcontinental railroads built over the last third of the 19th century created a nationwide transportation network that united the country by rail. The first of these, the "Pacific Railroad", was built by the Central Pacific Railroad and Union Pacific Railroad, as well as the Western Pacific Railroad (1862-1870), to link the San Francisco Bay at Alameda, California, with the nation's existing eastern railroad network at Omaha, Nebraska/Council Bluffs, Iowa — thereby creating the world's second transcontinental railroad when it was completed from Omaha to Alameda on September 6, 1869. (The first transcontinental railroad was the Panama Railroad of 1855.) Its construction was made possible by the US government under Pacific Railroad Acts of 1862, 1864, and 1867. Its original course was very close to current Interstate 80.
Transcontinental railroad
The U.S.'s first transcontinental railroad was built between 1863 and 1869 to join the eastern and western halves of the United States. Begun just before the American Civil War, its construction was considered to be one of the greatest American technological feats of the 19th century. Known as the "Pacific Railroad" when it opened, this served as a vital link for trade, commerce, and travel and opened up vast regions of the North American heartland for settlement. Shipping and commerce could thrive away from navigable watercourses for the first time since the beginning of the nation. Much of this route, especially on the Sierra grade west of Reno, Nevada, is currently used by Amtrak's California Zephy |
https://en.wikipedia.org/wiki/Mathematical%20optimization | Mathematical optimization (alternatively spelled optimisation) or mathematical programming is the selection of a best element, with regard to some criterion, from some set of available alternatives. It is generally divided into two subfields: discrete optimization and continuous optimization. Optimization problems arise in all quantitative disciplines from computer science and engineering to operations research and economics, and the development of solution methods has been of interest in mathematics for centuries.
In the more general approach, an optimization problem consists of maximizing or minimizing a real function by systematically choosing input values from within an allowed set and computing the value of the function. The generalization of optimization theory and techniques to other formulations constitutes a large area of applied mathematics. More generally, optimization includes finding "best available" values of some objective function given a defined domain (or input), including a variety of different types of objective functions and different types of domains.
Optimization problems
Optimization problems can be divided into two categories, depending on whether the variables are continuous or discrete:
An optimization problem with discrete variables is known as a discrete optimization, in which an object such as an integer, permutation or graph must be found from a countable set.
A problem with continuous variables is known as a continuous optimization, in which optimal arguments from a continuous set must be found. They can include constrained problems and multimodal problems.
An optimization problem can be represented in the following way:
Given: a function from some set to the real numbers
Sought: an element such that for all ("minimization") or such that for all ("maximization").
Such a formulation is called an optimization problem or a mathematical programming problem (a term not directly related to computer programming, but still in use for example in linear programming – see History below). Many real-world and theoretical problems may be modeled in this general framework.
Since the following is valid
it suffices to solve only minimization problems. However, the opposite perspective of considering only maximization problems would be valid, too.
Problems formulated using this technique in the fields of physics may refer to the technique as energy minimization, speaking of the value of the function as representing the energy of the system being modeled. In machine learning, it is always necessary to continuously evaluate the quality of a data model by using a cost function where a minimum implies a set of possibly optimal parameters with an optimal (lowest) error.
Typically, is some subset of the Euclidean space , often specified by a set of constraints, equalities or inequalities that the members of have to satisfy. The domain of is called the search space or the choice set, while the elements of are c |
https://en.wikipedia.org/wiki/Motion%20compensation | Motion compensation in computing, is an algorithmic technique used to predict a frame in a video, given the previous and/or future frames by accounting for motion of the camera and/or objects in the video. It is employed in the encoding of video data for video compression, for example in the generation of MPEG-2 files. Motion compensation describes a picture in terms of the transformation of a reference picture to the current picture. The reference picture may be previous in time or even from the future. When images can be accurately synthesized from previously transmitted/stored images, the compression efficiency can be improved.
Motion compensation is one of the two key video compression techniques used in video coding standards, along with the discrete cosine transform (DCT). Most video coding standards, such as the H.26x and MPEG formats, typically use motion-compensated DCT hybrid coding, known as block motion compensation (BMC) or motion-compensated DCT (MC DCT).
Functionality
Motion compensation exploits the fact that, often, for many frames of a movie, the only difference between one frame and another is the result of either the camera moving or an object in the frame moving. In reference to a video file, this means much of the information that represents one frame will be the same as the information used in the next frame.
Using motion compensation, a video stream will contain some full (reference) frames; then the only information stored for the frames in between would be the information needed to transform the previous frame into the next frame.
Illustrated example
The following is a simplistic illustrated explanation of how motion compensation works. Two successive frames were captured from the movie Elephants Dream. As can be seen from the images, the bottom (motion compensated) difference between two frames contains significantly less detail than the prior images, and thus compresses much better than the rest. Thus the information that is required to encode compensated frame will be much smaller than with the difference frame. This also means that it is also possible to encode the information using difference image at a cost of less compression efficiency but by saving coding complexity without motion compensated coding; as a matter of fact that motion compensated coding (together with motion estimation, motion compensation) occupies more than 90% of encoding complexity.
MPEG
In MPEG, images are predicted from previous frames or bidirectionally from previous and future frames are more complex because the image sequence must be transmitted and stored out of order so that the future frame is available to generate the
After predicting frames using motion compensation, the coder finds the residual, which is then compressed and transmitted.
Global motion compensation
In global motion compensation, the motion model basically reflects camera motions such as:
Dolly — moving the camera forward or backward
Track — moving th |
https://en.wikipedia.org/wiki/Cylinder%20%28disambiguation%29 | A cylinder is a basic curvilinear geometric shape.
Cylinder may also refer to:
Cylinder (algebra), the Cartesian product of a set with its superset
Cylinder (disk drive), a division of data in a disk drive
Cylinder (engine), the space in which a piston travels in an engine
Cylinder (firearms), the rotating part of a revolver containing multiple chambers
Cylinder (gastropod), a subgenus of sea snails
Cylinder (locomotive), the components that convert steam power into motion
Cylinder (optometry)
Cylinder, Iowa, a city in Palo Alto County, Iowa, United States
Cylinder set, a natural basic set in product spaces
Cylinder set measure, a way to generate a measure over product spaces
Gas cylinder, a high-strength container for storing gases at high pressure
Phonograph cylinder, the earliest commercial medium for recording and reproducing sound
See also
Cylindera, a genus of ground beetles |
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