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Cryptovirology
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deniable password snatching cryptovirus installs cryptotrojan asymmetrically encrypts host data covertly broadcasts it.makes available everyone noticeable one except attacker decipherable attacker.attacker caught installing cryptotrojan claims virus victim.attacker observed receiving covert asymmetric broadcast one thousands millions receivers exhibits identifying information whatsoever.cryptovirology attack achieves endtoend deniability.
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Cryptovirology
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covert asymmetric broadcast victims data.cryptovirology also encompasses use private information retrieval pir allow cryptoviruses search steal host data without revealing data searched even cryptotrojan constant surveillance.definition cryptovirus carries within coding sequence query attacker necessary pir logic apply query host systems.history first cryptovirology attack invented adam l. young moti yung called cryptoviral extortion presented ieee security privacy conference.attack cryptovirus cryptoworm cryptotrojan contains public key attacker hybrid encrypts victims files.
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Cryptovirology
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malware prompts user send asymmetric ciphertext attacker decipher return symmetric decryption key contains fee.victim needs symmetric key decrypt encrypted files way recover original files e.g.backups.ieee paper predicted cryptoviral extortion attackers would one day demand emoney long bitcoin even existed.many years later media relabeled cryptoviral extortion ransomware.
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Cryptovirology
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cryptovirology attacks healthcare providers reached epidemic levels prompting u.s. department health human services issue fact sheet ransomware andhipaa.the fact sheet states electronic protected health information encrypted ransomware breach occurred attack therefore constitutes disclosure permitted hipaa rationale adversary taken control information.sensitive data might never leave victim organization breakin may allowed data sent undetected.california enacted law defines introduction ransomware computer system intent extortion law.examples tremor virus viruses wild used cryptography past purpose usage cryptography avoid detection antivirus software.example tremor virus used polymorphism defensive technique attempt avoid detection antivirus software.
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Cryptovirology
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though cryptography assist cases enhance longevity virus capabilities cryptography used payload.onehalf virus amongst first viruses known encrypted affected files.troransom.a virus example virus informs owner infected machine pay ransom virus nicknamed troransom.a.virus asks owner infected machine send .given account western union.virus.win.gpcode.ag classic cryptovirus.
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Cryptovirology
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virus partially uses version bit rsa encrypts files many different extensions.instructs owner machine email given mail id owner desires decryptor.contacted email user asked pay certain amount ransom return decryptor.capi demonstrated using different calls microsofts cryptographic api capi cryptovirus satisfy encryption needs.uses cryptographyenabled malware apart cryptoviral extortion potential uses cryptoviruses deniable password snatching cryptocountersprivate information retrieval secure communication different instances distributed cryptovirus.
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File system
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references external links cryptovirology labs site maintained adam young moti yungcryptography cryptovirology articles vx heavens archived wayback machine computer virusescryzip trojan encrypts files demands ransomcan virus lead enterprise courta student report entitled superworms cryptovirologynext virus generation overview cryptoviruses angelo p. e. rosiellowithout file system data placed storage medium would one large body data way tell one piece data stopped next began piece data located time retrieve it.separating data pieces giving piece name data easily isolated identified.taking name way paperbased data management system named group data called file.structure logic rules used manage groups data names called file system.there many different kinds file systems.one different structure logic properties speed flexibility security size more.
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File system
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file systems designed used specific applications.example iso file system designed specifically optical discs.file systems used numerous different types storage devices use different kinds media.hard disk drives key storage devices projected remain foreseeable future.kinds media used include ssds magnetic tapes optical discs.cases tmpfs computers main memory randomaccess memory ram used create temporary file system shortterm use.some file systems used local data storage devices others provide file access via network protocol example nfs smb p clients.
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File system
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file systems virtual meaning supplied files called virtual files computed request procfs sysfs merely mapping different file system used backing store.file system manages access content files metadata files.responsible arranging storage space reliability efficiency tuning regard physical storage medium important design considerations.origin term advent computers term file system used describe method storing retrieving paper documents.term applied computerized filing alongside original meaning.
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File system
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general use.architecture file system consists two three layers.sometimes layers explicitly separated sometimes functions combined.the logical file system responsible interaction user application.provides application program interface api file operations — open close read etc.passes requested operation layer processing.
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File system
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logical file system manages open file table entries perprocess file descriptors.layer provides file access directory operations security protection.the second optional layer virtual file system.interface allows support multiple concurrent instances physical file systems called file system implementation.the third layer physical file system.layer concerned physical operation storage device e.g.disk.
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File system
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processes physical blocks read written.handles buffering memory management responsible physical placement blocks specific locations storage medium.physical file system interacts device drivers channel drive storage device.aspects file systems space management note applies file systems used storage devices.file systems allocate space granular manner usually multiple physical units device.file system responsible organizing files directories keeping track areas media belong file used.
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File system
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example apple dos early byte sectors kilobyte floppy disk used tracksector map.this results unused space file exact multiple allocation unit sometimes referred slack space.byte allocation average unused space bytes.kb clusters average unused space kb.size allocation unit chosen file system created.choosing allocation size based average size files expected file system minimize amount unusable space.
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File system
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frequently default allocation may provide reasonable usage.choosing allocation size small results excessive overhead file system contain mostly large files.file system fragmentation occurs unused space single files contiguous.file system used files created modified deleted.file created file system allocates space data.file systems permit require specifying initial space allocation subsequent incremental allocations file grows.
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File system
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files deleted space allocated eventually considered available use files.creates alternating used unused areas various sizes.free space fragmentation.file created area contiguous space available initial allocation space must assigned fragments.file modified becomes larger may exceed space initially allocated another allocation must assigned elsewhere file becomes fragmented.in operating systems system administrator may use disk quotas limit allocation disk space.
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File system
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filenames filename file name used identify storage location file system.file systems restrictions length filenames.file systems filenames case sensitive i.e.names myfile myfile refer file directory others filenames case sensitive i.e.names myfile myfile myfile refer three separate files directory.most modern file systems allow filenames contain wide range characters unicode character set.
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File system
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however may restrictions use certain special characters disallowing within filenames characters might used indicate device device type directory prefix file path separator file type.directories file systems typically directories also called folders allow user group files separate collections.may implemented associating file name index table contents inode unixlike file system.directory structures may flat i.e.linear allow hierarchies directories may contain subdirectories.
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File system
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first file system support arbitrary hierarchies directories used multics operating system.native file systems unixlike systems also support arbitrary directory hierarchies example apples hierarchical file system successor hfs classic mac os fat file system msdos .later versions msdos microsoft windows ntfs file system windows nt family operating systems ods ondisk structure higher levels files file system openvms.metadata bookkeeping information typically associated file within file system.length data contained file may stored number blocks allocated file byte count.
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File system
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time file last modified may stored files timestamp.file systems might store file creation time time last accessed time files metadata changed time file last backed up.information include files device type e.g.block character socket subdirectory etc.owner user id group id access permissions file attributes e.g.
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File system
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whether file readonly executable etc..a file system stores metadata associated file—including file name length contents file location file folder hierarchy—separate contents file.most file systems store names files one directory one place—the directory table directory—which often stored like file.many file systems put metadata file directory table rest metadata file completely separate structure inode.most file systems also store metadata associated one particular file.such metadata includes information unused regions—free space bitmap block availability map—and information bad sectors.often information allocation group stored inside allocation group itself.additional attributes associated file systems ntfs xfs ext ext versions ufs hfs using extended file attributes.file systems provide user defined attributes author document character encoding document size image.some file systems allow different data collections associated one file name.separate collections may referred streams forks.apple long used forked file system macintosh microsoft supports streams ntfs.file systems maintain multiple past revisions file single file name filename retrieves recent version prior saved version accessed using special naming convention filename filename access version four saves ago.see comparison file systemsmetadata details file systems support kinds metadata.
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File system
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file system abstract user interface cases file system may make use storage device used organize represent access data whether stored dynamically generated e.g.procfs.utilities file systems include utilities initialize alter parameters remove instance file system.include ability extend truncate space allocated file system.directory utilities may used create rename delete directory entries also known dentries singular dentry alter metadata associated directory.directory utilities may also include capabilities create additional links directory hard links unix rename parent links .. unixlike operating systems create bidirectional links files.file utilities create list copy move delete files alter metadata.
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File system
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may able truncate data truncate extend space allocation append move modify files inplace.depending underlying structure file system may provide mechanism prepend truncate beginning file insert entries middle file delete entries file.utilities free space deleted files file system provides undelete function also belong category.some file systems defer operations reorganization free space secure erasing free space rebuilding hierarchical structures providing utilities perform functions times minimal activity.example file system defragmentation utilities.some important features file system utilities supervisory activities may involve bypassing ownership direct access underlying device.include highperformance backup recovery data replication reorganization various data structures allocation tables within file system.
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File system
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restricting permitting access several mechanisms used file systems control access data.usually intent prevent reading modifying files user group users.another reason ensure data modified controlled way access may restricted specific program.examples include passwords stored metadata file elsewhere file permissions form permission bits access control lists capabilities.need file system utilities able access data media level reorganize structures provide efficient backup usually means effective polite users effective intruders.methods encrypting file data sometimes included file system.
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File system
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effective since need file system utilities know encryption seed effectively manage data.risks relying encryption include fact attacker copy data use brute force decrypt data.additionally losing seed means losing data.maintaining integrity one significant responsibility file system ensure file system structures secondary storage remain consistent regardless actions programs accessing file system.includes actions taken program modifying file system terminates abnormally neglects inform file system completed activities.
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File system
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may include updating metadata directory entry handling data buffered yet updated physical storage media.other failures file system must deal include media failures loss connection remote systems.in event operating system failure soft power failure special routines file system must invoked similar individual program fails.the file system must also able correct damaged structures.may occur result operating system failure os unable notify file system power failure reset.the file system must also record events allow analysis systemic issues well problems specific files directories.user data important purpose file system manage user data.includes storing retrieving updating data.some file systems accept data storage stream bytes collected stored manner efficient media.program retrieves data specifies size memory buffer file system transfers data media buffer.
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File system
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runtime library routine may sometimes allow user program define record based library call specifying length.user program reads data library retrieves data via file system returns record.some file systems allow specification fixed record length used writes reads.facilitates locating nth record well updating records.an identification record also known key makes sophisticated file system.user program read write update records without regard location.requires complicated management blocks media usually separating key blocks data blocks.
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File system
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efficient algorithms developed pyramid structures locating records.using file system utilities language specific runtime libraries user programs use file system apis make requests file system.include data transfer positioning updating metadata managing directories managing access specifications removal.multiple file systems within single system frequently retail systems configured single file system occupying entire storage device.another approach partition disk several file systems different attributes used.one file system use browser cache email storage might configured small allocation size.
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File system
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keeps activity creating deleting files typical browser activity narrow area disk interfere file allocations.another partition might created storage audio video files relatively large block size.yet another may normally set readonly periodically set writable.a third approach mostly used cloud systems use disk images house additional file systems attributes within another host file system file.common example virtualization one user run experimental linux distribution using ext file system virtual machine hisher production windows environment using ntfs.ext file system resides disk image treated file multiple files depending hypervisor settings ntfs host file system.having multiple file systems single system additional benefit event corruption single partition remaining file systems frequently still intact.
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File system
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includes virus destruction system partition even system boot.file system utilities require dedicated access effectively completed piecemeal.addition defragmentation may effective.several system maintenance utilities virus scans backups also processed segments.example necessary backup file system containing videos along files none added since last backup.
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File system
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image files one easily spin differential images contain new data written master original image.differential images used safety concerns disposable system quickly restored destroyed contaminated virus old image removed new image created matter seconds even without automated procedures quick virtual machine deployment since differential images quickly spawned using script batches.design limitations file systems functional limit defines maximum storable data capacity within system.functional limits bestguess effort designer based large storage systems right large storage systems likely become future.disk storage continued increase near exponential rates see moores law years file systems kept reaching design limitations require computer users repeatedly move newer system evergreater capacity.file system complexity typically varies proportionally available storage capacity.
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File system
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file systems early home computers kb kb storage would reasonable choice modern storage systems hundreds gigabytes capacity.likewise modern file systems would reasonable choice early systems since complexity modern file system structures would quickly consume even exceed limited capacity early storage systems.types file systems file system types classified disktape file systems network file systems specialpurpose file systems.disk file systems disk file system takes advantages ability disk storage media randomly address data short amount time.additional considerations include speed accessing data following initially requested anticipation following data may also requested.
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File system
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permits multiple users processes access various data disk without regard sequential location data.examples include fat fat fat fat exfat ntfs hfs hfs hpfs apfs ufs ext ext ext xfs btrfs files veritas file system vmfs zfs reiserfs scoutfs.disk file systems journaling file systems versioning file systems.optical discs iso universal disk format udf two common formats target compact discs dvds bluray discs.mount rainier extension udf supported since .
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File system
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series linux kernel since windows vista facilitates rewriting dvds.flash file systems flash file system considers special abilities performance restrictions flash memory devices.frequently disk file system use flash memory device underlying storage media much better use file system specifically designed flash device.tape file systems tape file system file system tape format designed store files tape.magnetic tapes sequential storage media significantly longer random data access times disks posing challenges creation efficient management generalpurpose file system.in disk file system typically master file directory map used free data regions.
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File system
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file additions changes removals require updating directory usedfree maps.random access data regions measured milliseconds system works well disks.tape requires linear motion wind unwind potentially long reels media.tape motion may take several seconds several minutes move readwrite head one end tape other.consequently master file directory usage map extremely slow inefficient tape.writing typically involves reading block usage map find free blocks writing updating usage map directory add data advancing tape write data correct spot.additional file write requires updating map directory writing data may take several seconds occur file.tape file systems instead typically allow file directory spread across tape intermixed data referred streaming timeconsuming repeated tape motions required write new data.however side effect design reading file directory tape usually requires scanning entire tape read scattered directory entries.
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File system
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data archiving software works tape storage store local copy tape catalog disk file system adding files tape done quickly without rescan tape media.local tape catalog copy usually discarded used specified period time point tape must rescanned used future.ibm developed file system tape called linear tape file system.ibm implementation file system released opensource ibm linear tape file system — single drive edition ltfssde product.linear tape file system uses separate partition tape record index metadata thereby avoiding problems associated scattering directory entries across entire tape.tape formatting writing data tape erasing formatting tape often significantly timeconsuming process take several hours large tapes.
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File system
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many data tape technologies necessary format tape overwriting new data tape.due inherently destructive nature overwriting data sequential media.because time take format tape typically tapes preformatted tape user need spend time preparing new tape use.usually necessary write identifying media label tape use even automatically written software new tape used first time.database file systems another concept file management idea databasebased file system.instead addition hierarchical structured management files identified characteristics like type file topic author similar rich metadata.ibm db formerly known db db ios database file system part object based ibm operating system formerly known os ios incorporating single level store running ibm power systems formerly known iseries designed frank g. soltis ibms former chief scientist ibm i. around frank g. soltis team ibm rochester successfully designed applied technologies like database file system others like microsoft later failed accomplish.
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File system
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technologies informally known fortress rochester basic aspects extended early mainframe technologies many ways advanced technological perspective.some projects arent pure database file systems use aspects database file systemmany web content management systems use relational dbms store retrieve files.example xhtml files stored xml text fields image files stored blob fields sql select optional xpath statements retrieve files allow use sophisticated logic rich information associations usual file systems.many cmss also option storing metadata within database standard filesystem used store content files.very large file systems embodied applications like apache hadoop google file system use database file system concepts.transactional file systems programs need either make multiple file system changes one changes fail reason make none changes.example program installing updating software may write executables libraries andor configuration files.
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File system
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writing fails software left partially installed updated software may broken unusable.incomplete update key system utility command shell may leave entire system unusable state.transaction processing introduces atomicity guarantee ensuring operations inside transaction either committed transaction aborted system discards partial results.means crash power failure recovery stored state consistent.either software completely installed failed installation completely rolled back unusable partial install left system.transactions also provide isolation guarantee meaning operations within transaction hidden threads system transaction commits interfering operations system properly serialized transaction.windows beginning vista added transaction support ntfs feature called transactional ntfs use discouraged.
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File system
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number research prototypes transactional file systems unix systems including valor file system amino lfs transactional ext file system txos kernel well transactional file systems targeting embedded systems tffs.ensuring consistency across multiple file system operations difficult impossible without file system transactions.file locking used concurrency control mechanism individual files typically protect directory structure file metadata.instance file locking cannot prevent tocttou race conditions symbolic links.file locking also cannot automatically roll back failed operation software upgrade requires atomicity.journaling file systems one technique used introduce transactionlevel consistency file system structures.journal transactions exposed programs part os api used internally ensure consistency granularity single system call.data backup systems typically provide support direct backup data stored transactional manner makes recovery reliable consistent data sets difficult.backup software simply notes files changed since certain time regardless transactional state shared across multiple files overall dataset.
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File system
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workaround database systems simply produce archived state file containing data point backup software backs interact directly active transactional databases all.recovery requires separate recreation database state file file restored backup software.network file systems network file system file system acts client remote file access protocol providing access files server.programs using local interfaces transparently create manage access hierarchical directories files remote networkconnected computers.examples network file systems include clients nfs afs smb protocols filesystemlike clients ftp webdav.
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File system
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shared disk file systems shared disk file system one number machines usually servers access external disk subsystem usually san.file system arbitrates access subsystem preventing write collisions.examples include gfs red hat gpfs known spectrum scale ibm sfs dataplow cxfs sgi stornext quantum corporation scoutfs versity.special file systems special file system presents nonfile elements operating system files acted using file system apis.commonly done unixlike operating systems devices given file names nonunixlike operating systems well.
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File system
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device file systems device file system represents io devices pseudodevices files called device files.examples unixlike systems include devfs linux .systems udev.nonunixlike systems tops operating systems influenced full filename pathname file include device prefix devices containing file systems referred device prefix specifying device without anything following it.special file systems linux kernel configfs sysfs provide files used query kernel information configure entities kernel.procfs maps processes linux operating system structures filespace.
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File system
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minimal file system audiocassette storage disk digital tape devices expensive early microcomputer users.inexpensive basic data storage system devised used common audio cassette tape.when system needed write data user notified press record cassette recorder press return keyboard notify system cassette recorder recording.system wrote sound provide time synchronization modulated sounds encoded prefix data checksum suffix.system needed read data user instructed press play cassette recorder.system would listen sounds tape waiting burst sound could recognized synchronization.
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File system
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system would interpret subsequent sounds data.data read complete system would notify user press stop cassette recorder.primitive mostly worked.data stored sequentially usually unnamed format although systems commodore pet series computers allow files named.multiple sets data could written located fastforwarding tape observing tape counter find approximate start next data region tape.
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File system
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user might listen sounds find right spot begin playing next data region.implementations even included audible sounds interspersed data.flat file systems flat file system subdirectories directory entries files stored single directory.when floppy disk media first available type file system adequate due relatively small amount data space available.cpm machines featured flat file system files could assigned one user areas generic file operations narrowed work one instead defaulting work them.user areas special attributes associated files necessary define specific quota areas files could added groups long still free storage space disk.
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File system
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early apple macintosh also featured flat file system macintosh file system.unusual file management program macintosh finder created illusion partially hierarchical filing system top emfs.structure required every file unique name even appeared separate folder.ibm dos os store entries files disk pack volume directory pack called volume table contents vtoc.while simple flat file systems become awkward number files grows makes difficult organize data related groups files.a recent addition flat file system family amazons remote storage service intentionally simplistic allow users ability customize data stored.constructs buckets imagine disk drive unlimited size objects similar identical standard concept file.
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File system
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advanced file management allowed able use nearly character including objects name ability select subsets buckets content based identical prefixes.file systems operating systems many operating systems include support one file system.sometimes os file system tightly interwoven difficult separate file system functions.there needs interface provided operating system software user file system.interface textual provided command line interface unix shell openvms dcl graphical provided graphical user interface file browsers.graphical metaphor folder containing documents files nested folders often used see also directory folder.
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File system
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unix unixlike operating systems unixlike operating systems create virtual file system makes files devices appear exist single hierarchy.means systems one root directory every file existing system located somewhere.unixlike systems use ram disk network shared resource root directory.unixlike systems assign device name device files device accessed.instead gain access files another device operating system must first informed directory tree files appear.process called mounting file system.
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File system
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example access files cdrom one must tell operating system take file system cdrom make appear suchandsuch directory.directory given operating system called mount point – might example media.media directory exists many unix systems specified filesystem hierarchy standard intended specifically use mount point removable media cds dvds usb drives floppy disks.may empty may contain subdirectories mounting individual devices.generally administrator i.e.
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File system
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root user may authorize mounting file systems.unixlike operating systems often include software tools assist mounting process provide new functionality.strategies coined automounting reflection purpose.in many situations file systems root need available soon operating system booted.unixlike systems therefore provide facility mounting file systems boot time.system administrators define file systems configuration file fstab vfstab solaris also indicates options mount points.in situations need mount certain file systems boot time although use may desired thereafter.utilities unixlike systems allow mounting predefined file systems upon demand.removable media allow programs data transferred machines without physical connection.
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File system
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common examples include usb flash drives cdroms dvds.utilities therefore developed detect presence availability medium mount medium without user intervention.progressive unixlike systems also introduced concept called supermounting see example linux supermountng project.example floppy disk supermounted physically removed system.normal circumstances disk synchronized unmounted removal.provided synchronization occurred different disk inserted drive.
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File system
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system automatically notices disk changed updates mount point contents reflect new medium.an automounter automatically mount file system reference made directory atop mounted.usually used file systems network servers rather relying events insertion media would appropriate removable media.linux linux supports numerous file systems common choices system disk block device include ext family ext ext ext xfs jfs btrfs.raw flash without flash translation layer ftl memory technology device mtd ubifs jffs yaffs among others.squashfs common compressed readonly file system.
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File system
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solaris solaris earlier releases defaulted nonjournaled nonlogging ufs bootable supplementary file systems.solaris defaulted supported extended ufs.support file systems significant enhancements added time including veritas software corp. journaling vxfs sun microsystems clustering qfs sun microsystems journaling ufs sun microsystems open source poolable bit compressible errorcorrecting zfs.kernel extensions added solaris allow bootable veritas vxfs operation.logging journaling added ufs suns solaris .releases solaris solaris express opensolaris open source variants solaris operating system later supported bootable zfs.logical volume management allows spanning file system across multiple devices purpose adding redundancy capacity andor throughput.legacy environments solaris may use solaris volume manager formerly known solstice disksuite.
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File system
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multiple operating systems including solaris may use veritas volume manager.modern solaris based operating systems eclipse need volume management leveraging virtual storage pools zfs.macos macos formerly mac os x uses apple file system apfs replaced file system inherited classic mac os called hfs plus hfs.apple also uses term mac os extended hfs.hfs plus metadatarich casepreserving usually caseinsensitive file system.
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File system
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due unix roots macos unix permissions added hfs plus.later versions hfs plus added journaling prevent corruption file system structure introduced number optimizations allocation algorithms attempt defragment files automatically without requiring external defragmenter.filenames characters.hfs plus uses unicode store filenames.macos filetype come type code stored files metadata filename extension.hfs plus three kinds links unixstyle hard links unixstyle symbolic links aliases.aliases designed maintain link original file even moved renamed interpreted file system file manager code userland.macos .
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File system
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high sierra announced june apples wwdc event uses apple file system solidstate drives.macos also supported ufs file system derived bsd unix fast file system via nextstep.however mac os x leopard macos could longer installed ufs volume preleopard system installed ufs volume upgraded leopard.mac os x lion ufs support completely dropped.newer versions macos capable reading writing legacy fat file systems common windows.also capable reading newer ntfs file systems windows.order write ntfs file systems macos versions prior mac os x snow leopard third party software necessary.
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File system
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mac os x .snow leopard later allow writing ntfs file systems nontrivial system setting change third party software exists automates this.finally macos supports reading writing exfat file system since mac os x snow leopard starting version ... os os .introduced high performance file system hpfs.hpfs supports mixed case file names different code pages long file names characters efficient use disk space architecture keeps related items close disk volume less fragmentation data extentbased space allocation b tree structure directories root directory located midpoint disk faster average access.journaled filesystem jfs shipped .
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File system
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pcbsd pcbsd desktop version freebsd inherits freebsds zfs support similarly freenas.new graphical installer pcbsd handle root zfs raidz pool installs disk encryption using geli right start easy convenient gui way.current pcbsd .isotope edition zfs filesystem version zfs storage pool version .plan plan bell labs treats everything file accesses objects file would accessed i.e.
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File system
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ioctl mmap networking graphics debugging authentication capabilities encryption services accessed via io operations file descriptors.p protocol removes difference local remote files.file systems plan organized help private perprocess namespaces allowing process different view many file systems provide resources distributed system.the inferno operating system shares concepts plan .microsoft windows windows makes use fat ntfs exfat live file system refs file systems last supported usable windows server windows server windows windows .windows windows cannot boot it.windows uses drive letter abstraction user level distinguish one disk partition another.
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File system
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example path cwindows represents directory windows partition represented letter c. drive c commonly used primary hard disk drive partition windows usually installed boots.tradition become firmly ingrained bugs exist many applications make assumptions drive operating system installed c. use drive letters tradition using c drive letter primary hard disk drive partition traced msdos letters b reserved two floppy disk drives.turn derived cpm ultimately ibms cpcms .fat family fat file systems supported almost operating systems personal computers including versions windows msdospc dos os drdos.pc dos oem version msdos msdos originally based scps dos.
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File system
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drdos based digital researchs concurrent dos successor cpm.fat file systems therefore wellsuited universal exchange format computers devices type age.the fat file system traces roots back incompatible bit fat precursor standalone disk basic shortlived mdosmidas project.over years file system expanded fat fat fat.various features added file system including subdirectories codepage support extended attributes long filenames.third parties digital research incorporated optional support deletion tracking volumedirectoryfilebased multiuser security schemes support file directory passwords permissions readwriteexecutedelete access rights.extensions supported windows.the fat fat file systems limit number entries root directory file system restrictions maximum size fatformatted disks partitions.fat addresses limitations fat fat except file size limit close gb remains limited compared ntfs.fat fat fat also limit eight characters file name three characters extension .exe.
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File system
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commonly referred .filename limit.vfat optional extension fat fat fat introduced windows windows nt .allowed long file names lfn stored fat file system backwards compatible fashion.ntfs ntfs introduced windows nt operating system allowed aclbased permission control.
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File system
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features also supported ntfs include hard links multiple file streams attribute indexing quota tracking sparse files encryption compression reparse points directories working mountpoints file systems symlinks junctions remote storage links.exfat exfat certain advantages ntfs regard file system overhead.exfat backward compatible fat file systems fat fat fat.file system supported newer windows systems windows xp windows server windows vista windows windows windows windows .exfat supported macos starting version .. snow leopard.support operating systems sparse since implementing support exfat requires license.exfat file system fully supported macos windows hold files larger gb.
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File system
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openvms mvs prior introduction vsam os systems implemented hybrid file system.system designed easily support removable disk packs information relating files one disk volume ibm terminology stored disk flat system file called volume table contents vtoc.vtoc stores metadata file.later hierarchical directory structure imposed introduction system catalog optionally catalog files datasets resident removable volumes.catalog contains information relate dataset specific volume.
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File system
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user requests access dataset offline volume suitable privileges system attempt mount required volume.cataloged noncataloged datasets still accessed using information vtoc bypassing catalog required volume id provided open request.still later vtoc indexed speed access.conversational monitor system ibm conversational monitor system cms component vm uses separate flat file system virtual disk minidisk.file data control information scattered intermixed.
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File system
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anchor record called master file directory mfd always located fourth block disk.originally cms used fixedlength byte blocks later versions used larger size blocks k. access data record requires two levels indirection files directory entry called file status table fst entry points blocks containing list addresses individual records.file system data successors consists system objects mapped system virtual address space singlelevel store.many types objects defined including directories files found file systems.file objects along types objects form basis ass support integrated relational database.
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File system
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file systems prospero file system file system based virtual system model.system created dr. b. clifford neuman information sciences institute university southern california.rsre flex file system written algol file system michigan terminal system mts interesting provides line files record lengths line numbers associated metadata record file lines added replaced updated different length records deleted anywhere file without need read rewrite entire file ii using program keys files may shared permitted commands programs addition users groups iii comprehensive file locking mechanism protects files data metadata.limitations converting type file system may advantageous necessary files different file system currently exist.reasons include need increase space requirements beyond limits current file system.depth path may need increased beyond restrictions file system.
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File system
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may performance reliability considerations.providing access another operating system support existing file system another reason.inplace conversion cases conversion done inplace although migrating file system conservative involves creating copy data recommended.windows fat fat file systems converted ntfs via convert.exe utility reverse.linux ext converted ext converted back ext converted ext back ext ext converted btrfs converted back undo information deleted.
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File system
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conversions possible due using format file data relocating metadata empty space cases using sparse file support.migrating different file system migration disadvantage requiring additional space although may faster.best case unused space media contain final file system.for example migrate fat file system ext file system.first create new ext file system copy data file system delete fat file system.an alternative sufficient space retain original file system new one created use work area removable media.takes longer backup data nice side effect.
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File system
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long file paths long file names hierarchical file systems files accessed means path branching list directories containing file.different file systems different limits depth path.file systems also limit length individual filename.copying files long names located paths significant depth one file system another may cause undesirable results.depends utility copying handles discrepancy.see also notes references sources reading books online external links filesystem specifications links whitepapers.
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Palm oil
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archived original .cite web cs maint unfit url linkinteresting file system projectsoil used food manufacturing beauty products biofuel.palm oil accounted global oils produced oil crops .the use palm oil attracted concern environmental groups due deforestation tropics palms grown cited factor social problems due allegations human rights violations among growers.industry group formed create sustainable ethical palm oil roundtable sustainable palm oil.however little palm oil certified organization groups criticized greenwashing.history humans used oil palms far back years.
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Palm oil
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late archaeologists discovered substance concluded originally palm oil tomb abydos dating back bce.believed traders brought oil palm egypt.palm oil e. guineensis long recognized west central african countries used widely cooking oil.european merchants trading west africa occasionally purchased palm oil use cooking oil europe.palm oil became highly soughtafter commodity british traders use industrial lubricant machinery britains industrial revolution.palm oil formed basis soap products lever brothers unilever sunlight soap american palmolive brand.by around palm oil constituted primary export west african countries although overtaken cocoa introduction colonial european cocoa plantations.processing palm oil naturally reddish color high betacarotene content.
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Palm oil
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confused palm kernel oil derived kernel fruit coconut oil derived kernel coconut palm cocos nucifera.differences color raw palm kernel oil lacks carotenoids red saturated fat content palm mesocarp oil saturated palm kernel oil coconut oil saturated fats respectively.however crude red palm oil refined neutralized bleached deodorized common commodity called rbd refined bleached deodorized palm oil contain carotenoids.many industrial food applications palm oil use fractionated components palm oil often listed modified palm oil whose saturation levels reach modified palm oils become highly saturated necessarily hydrogenated.the oil palm produces bunches containing many fruits fleshy mesocarp enclosing kernel covered hard shell.fao considers palm oil coming pulp palm kernels primary products.
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Palm oil
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oil extraction rate bunch varies palm oil palm kernels.along coconut oil palm oil one highly saturated vegetable fats semisolid room temperature.palm oil common cooking ingredient tropical belt africa southeast asia parts brazil.use commercial food industry parts world widespread lower cost high oxidative stability saturation refined product used frying.one source reported humans consumed average pounds .kg palm oil per person .many processed foods either contain palm oil various ingredients made it.
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Palm oil
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refining milling various palm oil products made using refining processes.first fractionation crystallization separation processes obtain solid palm stearin liquid olein fractions.melting degumming removes impurities.oil filtered bleached.physical refining removes smells coloration produce refined bleached deodorized palm oil rbdpo free fatty acids used manufacture soaps washing powder products.
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Palm oil
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rbdpo basic palm oil product sold worlds commodity markets.many companies fractionate produce palm oil cooking oil process products.red palm oil since mids red palm oil coldpressed fruit oil palm bottled use cooking oil addition uses blended mayonnaise vegetable oil.oil produced palm fruit called red palm oil palm oil.around saturated fat—considerably less palm kernel oil—and unsaturated fat polyunsaturated fat.unprocessed state red palm oil intense deep red color abundant carotene content.
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Palm oil
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red palm oil also contains sterols vitamin e carotenoids alphacarotene betacarotene lycopene.white palm oil white palm oil result processing refining.refined palm oil loses deep red color.extensively used food manufacture found variety processed foods including peanut butter chips.often labeled palm shortening used replacement ingredient hydrogenated fats variety baked fried products.
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Palm oil
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uses food highly saturated nature palm oil renders solid room temperature temperate regions making cheap substitute butter hydrogenated vegetable oils uses solid fat desirable making pastry dough baked goods.health concerns related trans fats hydrogenated vegetable oils may contributed increasing use palm oil food industry.palm oil sometimes used minor ingredient calf milk replacer.nonfood consumer products palm oil pervasively used personal care cleaning products provides foaming agent nearly every soap shampoo detergent.around personal care products including soap shampoo makeup lotion contain ingredients derived palm oil.however different names palm oil ingredients include word “palm.
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Palm oil
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biomass biofuels palm oil used produce methyl ester hydrodeoxygenated biodiesel.palm oil methyl ester created process called transesterification.palm oil biodiesel often blended fuels create palm oil biodiesel blends.palm oil biodiesel meets european en standard biodiesels.hydrodeoxygenated biodiesel produced direct hydrogenolysis fat alkanes propane.
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Palm oil
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worlds largest palm oil biodiesel plant € million finnishoperated neste oil biodiesel plant singapore opened capacity tons per year produces hydrodeoxygenated nexbtl biodiesel palm oil imported malaysia indonesia.significant amounts palm oil exports europe converted biodiesel early indonesia malaysia .almost half palm oil europe burned car truck fuel.onehalf europes palm oil imports used biodiesel.use palm oil biodiesel generates three times carbon emissions using fossil fuel example biodiesel made indonesian palm oil makes global carbon problem worse better.there pressures increased oil palm production indonesian palmbased biodiesel programs.biodiesel currently contains palm oil conventional diesel ratio known b gas pumps.
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Palm oil
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indonesian government aiming produce palm oil biodiesel b transition using conventional diesel.indonesian government estimated would need establish approximately million hectares oil palm plantations meet future demands.the organic waste matter produced processing oil palm including oil palm shells oil palm fruit bunches also used produce energy.waste material converted pellets used biofuel.additionally palm oil used fry foods converted methyl esters biodiesel.used cooking oil chemically treated create biodiesel similar petroleum diesel.
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Palm oil
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wound care although palm oil applied wounds supposed antimicrobial effects research confirm effectiveness.production – world production palm oil .million metric tons .million short tons.annual production palm oil projected reach million metric tons million short tons .
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Palm oil
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indonesia indonesia worlds largest producer palm oil surpassing malaysia producing .million metric tons .million short tons number since risen .million metric tons .million short tons output.
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Palm oil
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indonesia expects double production end .number .million metric tons .million short tons.end output exported form crude palm oil.
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Palm oil
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fao data shows production increased .million metric tons .million short tons.malaysia malaysia worlds second largest producer palm oil.response concerns deforestation government malaysia pledged limit expansion palm oil plantations retaining minimum half nations land forest cover.in country produced .
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Palm oil
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million metric tons .million short tons crude palm oil roughly hectares sq mi land.though indonesia produces palm oil malaysia worlds largest exporter palm oil exported million metric tons million short tons palm oil products .india china pakistan european union united states primary importers malaysian palm oil products.palm oil prices jumped fouryear high days trumps election victory us.
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Palm oil
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nigeria nigeria thirdlargest producer approximately .million hectares .million acres cultivation.nigeria worlds largest producer.small largescale producers participated industry.
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Palm oil
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thailand thailand worlds third largest producer crude palm oil producing approximately million metric tons .million short tons per year .global output.nearly thai production consumed locally.almost palm plantations extraction mills south thailand.
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Palm oil
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yearend ..million rai hectares acres planted oil palms employing farmers mostly small landholdings rai .hectares .acres.
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Palm oil
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asean region accounts .million metric tons .million short tons palm oil production world total global exports.indonesia accounts world exports.malaysian exports total .
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Palm oil
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biggest consumers palm oil india european union china three consuming nearly world exports.thailands department internal trade dit usually sets price crude palm oil refined palm oil thai farmers relatively low yield compared malaysia indonesia.thai palm oil crops yield – oil compared around competing countries.addition indonesian malaysian oil palm plantations times size thai plantations.colombia total palm oil production colombia reached .
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Palm oil
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million metric tons .million short tons representing national agricultural gdp benefiting mainly smallholders colombias palm oil sector.according study environmental science policy colombia potential produce sustainable palm oil without causing deforestation.addition palm oil crops provide productive alternative illegal crops like coca.ecuador ecuador aims help palm oil producers switch sustainable methods achieve rspo certification initiatives develop greener industries.
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Palm oil
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benin palm native wetlands western africa south benin already hosts many palm plantations.agricultural revival programme identified many thousands hectares land suitable new oil palm export plantations.spite economic benefits nongovernmental organisations ngos nature tropicale claim biofuels compete domestic food production existing prime agricultural sites.areas comprise peat land whose drainage would deleterious environmental impact.also concerned genetically modified plants introduced region jeopardizing current premium paid nongm crops.according recent article national geographic palm oil benin still produced women domestic use.
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Palm oil
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fao additionally states peasants benin practice agroecology.harvest palm fruit small farms palm oil mostly used local consumption.cameroon cameroon production project underway initiated herakles farms us.however project halted pressure civil society organizations cameroon.project halted herakles left roundtable sustainable palm oil early negotiations.
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Palm oil
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project controversial due opposition villagers location project sensitive region biodiversity.kenya kenyas domestic production edible oils covers third annual demand estimated around metric tons short tons.rest imported cost around us million year making edible oil countrys second important import petroleum.since new hybrid variety coldtolerant highyielding oil palm promoted food agriculture organization united nations western kenya.well alleviating countrys deficit edible oils providing important cash crop claimed environmental benefits region compete food crops native vegetation provides stabilisation soil.
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Palm oil
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ghana ghana lot palm nut species may become important contributor agriculture region.although ghana multiple palm species ranging local palm nuts species locally called agric marketed locally neighboring countries.production expanding major investment funds purchasing plantations ghana considered major growth area palm oil.social environmental impacts forests cleared parts indonesia malaysia make space oilpalm monoculture.significant impacts local ecosystems leading deforestation biodiversity loss.
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Palm oil
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example processes resulted significant acreage losses natural habitat three surviving species orangutan.one species particular sumatran orangutan listed critically endangered habitat loss due palm oil cultivation.social addition environmental concerns palm oil development regions produce also led significant social conflict.regions fast growing palm oil production experienced significant violations indigenous land rights influxes illegal immigrant labor labor practices alleged related human rights violations.palm oil industry positive negative impacts workers indigenous peoples residents palm oilproducing communities.
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Palm oil
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palm oil production provides employment opportunities shown improve infrastructure social services reduce poverty.however cases oil palm plantations developed lands without consultation compensation indigenous people inhabiting land resulting social conflict.use illegal immigrants malaysia also raised concerns working conditions within palm oil industry.some social initiatives use palm oil cultivation part poverty alleviation strategies.examples include un food agriculture organisations hybrid oil palm project western kenya improves incomes diets local populations malaysias federal land development authority federal land consolidation rehabilitation authority support rural development.food vs. fuel use palm oil production biodiesel led concerns need fuel placed ahead need food leading malnutrition developing nations.
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Palm oil
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known food versus fuel debate.according report published renewable sustainable energy reviews palm oil determined sustainable source food biofuel production palm oil biodiesel pose threat edible palm oil supplies.according study published environmental science policy journal palm oil biodiesel might increase demand palm oil future resulting expansion palm oil production therefore increased supply food.human rights one report indicated numerous allegations human rights violations production palm oil indonesia malaysia including exposure hazardous pesticides child labor rape sexual abuse unsafe carrying loads.incidents may receive response company police left unreported victims fear retaliation abuser.
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Palm oil
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chemicals used pesticides paraquat glyphosate linked diseases parkinsons disease cancer.environmental worlds vegetable oil farmland used palm plantations palm cultivation produces worlds total vegetable oil supply.terms oil yield palm plantation times productive soybean sunflower rapeseed cultivation palm fruit kernel provide usable oil.palm oil garnered criticism environmentalists due environmental importance grown.however indisputably efficient comparison oilproducing plants.
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