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12,200 | SS General Hans Kammler, who as an engineer had constructed several concentration camps, including Auschwitz, had a reputation for brutality and had originated the idea of using concentration camp prisoners as slave laborers in the rocket program. Arthur Rudolph, chief engineer of the V-2 rocket factory at Peenemünde, endorsed this idea in April 1943 when a labor shortage developed. More people died building the V-2 rockets than were killed by it as a weapon. Von Braun admitted visiting the plant at Mittelwerk on many occasions, and called conditions at the plant "repulsive", but claimed never to have personally witnessed any deaths or beatings, although it had become clear to him by 1944 that deaths had occurred. He denied ever having visited the Mittelbau-Dora concentration camp itself, where 20,000 died from illness, beatings, hangings, and intolerable working conditions. | https://en.wikipedia.org/wiki?curid=33783 |
12,201 | Some prisoners claim von Braun engaged in brutal treatment or approved of it. Guy Morand, a French resistance fighter who was a prisoner in Dora, testified in 1995 that, after an apparent sabotage attempt, von Braun ordered a prisoner to be flogged, while Robert Cazabonne, another French prisoner, claimed von Braun stood by as prisoners were hanged by chains suspended by cranes. However, these accounts may have been a case of mistaken identity. Former Buchenwald inmate Adam Cabala claims that von Braun went to the concentration camp to pick slave laborers: | https://en.wikipedia.org/wiki?curid=33783 |
12,202 | ... also the German scientists led by Prof. Wernher von Braun were aware of everything daily. As they went along the corridors, they saw the exhaustion of the inmates, their arduous work and their pain. Not one single time did Prof. Wernher von Braun protest against this cruelty during his frequent stays at Dora. Even the aspect of corpses did not touch him: On a small area near the ambulance shed, inmates tortured to death by slave labor and the terror of the overseers were piling up daily. But, Prof. Wernher von Braun passed them so close that he was almost touching the corpses. | https://en.wikipedia.org/wiki?curid=33783 |
12,203 | Von Braun later claimed that he was aware of the treatment of prisoners, but felt helpless to change the situation. | https://en.wikipedia.org/wiki?curid=33783 |
12,204 | According to André Sellier, a French historian and survivor of the Mittelbau-Dora concentration camp, Heinrich Himmler had von Braun come to his Feldkommandostelle Hochwald HQ in East Prussia in February 1944. To increase his power-base within the Nazi regime, Himmler was conspiring to use Kammler to gain control of all German armament programs, including the V-2 program at Peenemünde. He therefore recommended that von Braun work more closely with Kammler to solve the problems of the V-2. Von Braun claimed to have replied that the problems were merely technical and he was confident that they would be solved with Dornberger's assistance. | https://en.wikipedia.org/wiki?curid=33783 |
12,205 | Von Braun had been under SD surveillance since October 1943. A secret report stated that he and his colleagues Klaus Riedel and Helmut Gröttrup were said to have expressed regret at an engineer's house one evening in early March 1944 that they were not working on a spaceship and that they felt the war was not going well; this was considered a "defeatist" attitude. A young female dentist who was an SS spy reported their comments. Combined with Himmler's false charges that von Braun and his colleagues were communist sympathizers and had attempted to sabotage the V-2 program, and considering that von Braun regularly piloted his government-provided airplane that might allow him to escape to Britain, this led to their arrest by the Gestapo. | https://en.wikipedia.org/wiki?curid=33783 |
12,206 | The unsuspecting von Braun was detained on 14 March (or 15 March), 1944, and was taken to a Gestapo cell in Stettin (now Szczecin, Poland). where he was held for two weeks without knowing the charges against him. | https://en.wikipedia.org/wiki?curid=33783 |
12,207 | Through Major Hans Georg Klamroth, in charge of the Abwehr for Peenemünde, Dornberger obtained von Braun's conditional release and Albert Speer, Reichsminister for Munitions and War Production, persuaded Hitler to reinstate von Braun so that the V-2 program could continue or turn into a "V-4 program" (the Rheinbote as a short range ballistic rocket) which in their view would be impossible without von Braun's leadership. In his memoirs, Speer states Hitler had finally conceded that von Braun was to be "protected from all prosecution as long as he is indispensable, difficult though the general consequences arising from the situation." | https://en.wikipedia.org/wiki?curid=33783 |
12,208 | Upon investigation by the United States Federal Bureau of Investigation on 1 May 1961 advised that “there was no record of an arrest in their respective files” suggesting that Von Braun’s imprisonment was wiped from German prison records at a point after his conditional release or after the Nazi regime had fallen. | https://en.wikipedia.org/wiki?curid=33783 |
12,209 | The Soviet Army was about from Peenemünde in early 1945 when von Braun assembled his planning staff and asked them to decide how and to whom they should surrender. Unwilling to go to the Soviets, von Braun and his staff decided to try to surrender to the Americans. Kammler had ordered relocation of his team to central Germany; however, a conflicting order from an army chief ordered them to join the army and fight. Deciding that Kammler's order was their best bet to defect to the Americans, von Braun fabricated documents and transported 500 of his affiliates to the area around Mittelwerk, where they resumed their work in Bleicherode and surrounding towns after the middle of February 1945. For fear of their documents being destroyed by the SS, von Braun ordered the blueprints to be hidden in an abandoned iron mine in the Harz mountain range near Goslar. The US Counterintelligence Corps managed to unveil the location after lengthy interrogations of von Braun, Walter Dornberger, Bernhard Tessmann and Dieter Huzel and recovered 14 tons of V-2 documents by 15 May 1945, from the British Occupation Zone. | https://en.wikipedia.org/wiki?curid=33783 |
12,210 | While on an official trip in March, von Braun suffered a complicated fracture of his left arm and shoulder in a car accident after his driver fell asleep at the wheel. His injuries were serious, but he insisted that his arm be set in a cast so he could leave the hospital. Due to this neglect of the injury he had to be hospitalized again a month later when his bones had to be rebroken and realigned. | https://en.wikipedia.org/wiki?curid=33783 |
12,211 | In early April, as the Allied forces advanced deeper into Germany, Kammler ordered the engineering team, around 450 specialists, to be moved by train into the town of Oberammergau in the Bavarian Alps, where they were closely guarded by the SS with orders to execute the team if they were about to fall into enemy hands. However, von Braun managed to convince SS Major Kummer to order the dispersal of the group into nearby villages so that they would not be an easy target for U.S. bombers. On 29 April 1945, Oberammergau was captured by the Allied forces who seized the majority of the engineering team. | https://en.wikipedia.org/wiki?curid=33783 |
12,212 | Nearing the end of the war, Hitler had instructed SS troops to gas all technical men concerned with rocket development. Upon hearing this, Von Braun commandeered a train, and fled with other “technical men” to a location in the mountains of South Germany. After some time, Von Braun and many of the others who made it to the mountains left their location to flee to advancing American lines in Austria. | https://en.wikipedia.org/wiki?curid=33783 |
12,213 | Von Braun and several members of the engineering team, including Dornberger, made it to Austria. On 2 May 1945, upon finding an American private from the U.S. 44th Infantry Division, von Braun's brother and fellow rocket engineer, Magnus, approached the soldier on a bicycle, calling out in broken English: "My name is Magnus von Braun. My brother invented the V-2. We want to surrender." After the surrender, Wernher von Braun spoke to the press: | https://en.wikipedia.org/wiki?curid=33783 |
12,214 | We knew that we had created a new means of warfare, and the question as to what nation, to what victorious nation we were willing to entrust this brainchild of ours was a moral decision more than anything else. We wanted to see the world spared another conflict such as Germany had just been through, and we felt that only by surrendering such a weapon to people who are guided not by the laws of materialism but by Christianity and humanity could such an assurance to the world be best secured. | https://en.wikipedia.org/wiki?curid=33783 |
12,215 | The American high command was well aware of how important their catch was: von Braun had been at the top of the "Black List", the code name for the list of German scientists and engineers targeted for immediate interrogation by U.S. military experts. On 9 June 1945, two days before the originally scheduled handover of the Nordhausen and Bleicherode area in Thuringia to the Soviets, U.S. Army Major Robert B. Staver, Chief of the Jet Propulsion Section of the Research and Intelligence Branch of the U.S. Army Ordnance Corps in London, and Lieutenant Colonel R. L. Williams took von Braun and his department chiefs by Jeep from Garmisch to Munich, from where they were flown to Nordhausen. In the following days, a larger group of rocket engineers, among them Helmut Gröttrup, was evacuated from Bleicherode southwest to Witzenhausen, a small town in the American Zone. | https://en.wikipedia.org/wiki?curid=33783 |
12,216 | Von Braun was briefly detained at the "Dustbin" interrogation center at Kransberg Castle, where the elite of Nazi Germany's economic, scientific and technological sectors were debriefed by U.S. and British intelligence officials. Initially, he was recruited to the U.S. under a program called Operation Overcast, subsequently known as Operation Paperclip. There is evidence, however, that British intelligence and scientists were the first to interview him in depth, eager to gain information that they knew U.S. officials would deny them. The team included the young L.S. Snell, then the leading British rocket engineer, later chief designer of Rolls-Royce Limited and inventor of the Concorde's engines. The specific information the British gleaned remained top secret, both from the Americans and from the other allies. | https://en.wikipedia.org/wiki?curid=33783 |
12,217 | On 20 June 1945, U.S. Secretary of State Edward Stettinius Jr. approved the transfer of von Braun and his specialists to the United States as one of his last acts in office; however, this was not announced to the public until 1 October 1945. | https://en.wikipedia.org/wiki?curid=33783 |
12,218 | The first seven technicians arrived in the United States at New Castle Army Air Field, just south of Wilmington, Delaware, on 20 September 1945. They were then flown to Boston, Massachusetts, and taken by boat to the Army Intelligence Service post at Fort Strong in Boston Harbor. Later, with the exception of von Braun, the men were transferred to Aberdeen Proving Ground in Maryland to sort out the Peenemünde documents, enabling the scientists to continue their rocketry experiments. | https://en.wikipedia.org/wiki?curid=33783 |
12,219 | Finally, von Braun and his remaining Peenemünde staff (see List of German rocket scientists in the United States) were transferred to their new home at Fort Bliss, a large Army installation just north of El Paso, Texas. Von Braun later wrote that he found it hard to develop a "genuine emotional attachment" to his new surroundings. His chief design engineer Walther Reidel became the subject of a December 1946 article "German Scientist Says American Cooking Tasteless; Dislikes Rubberized Chicken", exposing the presence of von Braun's team in the country and drawing criticism from Albert Einstein and John Dingell. Requests to improve their living conditions such as laying linoleum over their cracked wood flooring were rejected. Von Braun was hypercritical of the slowness of the United States development of guided missiles. His lab was never able to get sufficient funds to go on with their programs. Von Braun remarked, "at Peenemünde we had been coddled, here you were counting pennies". Whereas von Braun had thousands of engineers who answered to him at Peenemünde, he was now subordinate to "pimply" 26-year-old Jim Hamill, an Army major who possessed only an undergraduate degree in engineering. His loyal Germans still addressed him as "Herr Professor," but Hamill addressed him as "Wernher" and never responded to von Braun's request for more materials. Every proposal for new rocket ideas was dismissed. | https://en.wikipedia.org/wiki?curid=33783 |
12,220 | While at Fort Bliss, they trained military, industrial, and university personnel in the intricacies of rockets and guided missiles. As part of the Hermes project, they helped refurbish, assemble, and launch a number of V-2s that had been shipped from Allied-occupied Germany to the White Sands Proving Ground in New Mexico. They also continued to study the future potential of rockets for military and research applications. Since they were not permitted to leave Fort Bliss without military escort, von Braun and his colleagues began to refer to themselves only half-jokingly as "PoPs" – "Prisoners of Peace". | https://en.wikipedia.org/wiki?curid=33783 |
12,221 | In 1950, at the start of the Korean War, von Braun and his team were transferred to Huntsville, Alabama, his home for the next 20 years. Between 1952 and 1956, von Braun led the Army's rocket development team at Redstone Arsenal, resulting in the Redstone rocket, which was used for the first live nuclear ballistic missile tests conducted by the United States. He personally witnessed this historic launch and detonation. Work on the Redstone led to development of the first high-precision inertial guidance system on the Redstone rocket. | https://en.wikipedia.org/wiki?curid=33783 |
12,222 | As director of the Development Operations Division of the Army Ballistic Missile Agency, von Braun, with his team, then developed the Jupiter-C, a modified Redstone rocket. The Jupiter-C was the basis for the Juno I rocket that successfully launched the West's first satellite, Explorer 1, on 31 January 1958. This event signaled the birth of America's space program. | https://en.wikipedia.org/wiki?curid=33783 |
12,223 | Repeating the pattern he had established during his earlier career in Germany, von Braun – while directing military rocket development in the real world – continued to entertain his engineer-scientist's dream of a future in which rockets would be used for space exploration. However, he was no longer at risk of being fired. As American public opinion of Germans began to recover, von Braun found himself increasingly in a position to popularize his ideas. The 14 May 1950 headline of "The Huntsville Times" ("Dr. von Braun Says Rocket Flights Possible to Moon") might have marked the beginning of these efforts. Von Braun's ideas rode a publicity wave that was created by science fiction movies and stories. | https://en.wikipedia.org/wiki?curid=33783 |
12,224 | In 1952, von Braun first published his concept of a crewed space station in a "Collier's Weekly" magazine series of articles titled "Man Will Conquer Space Soon!". These articles were illustrated by the space artist Chesley Bonestell and were influential in spreading his ideas. Frequently, von Braun worked with fellow German-born space advocate and science writer Willy Ley to publish his concepts, which, unsurprisingly, were heavy on the engineering side and anticipated many technical aspects of space flight that later became reality. | https://en.wikipedia.org/wiki?curid=33783 |
12,225 | The space station (to be constructed using rockets with recoverable and reusable ascent stages) would be a toroid structure, with a diameter of ; this built on the concept of a rotating wheel-shaped station introduced in 1929 by Herman Potočnik in his book "The Problem of Space Travel – The Rocket Motor". The space station would spin around a central docking nave to provide artificial gravity, and would be assembled in a two-hour, high-inclination Earth orbit allowing observation of essentially every point on Earth on at least a daily basis. The ultimate purpose of the space station would be to provide an assembly platform for crewed lunar expeditions. More than a decade later, the movie version of would draw heavily on the design concept in its visualization of an orbital space station. | https://en.wikipedia.org/wiki?curid=33783 |
12,226 | Von Braun envisioned these expeditions as very large-scale undertakings, with a total of 50 astronauts traveling in three huge spacecraft (two for crew, one primarily for cargo), each long and in diameter and driven by a rectangular array of 30 rocket propulsion engines. Upon arrival, astronauts would establish a permanent lunar base in the Sinus Roris region by using the emptied cargo holds of their craft as shelters, and would explore their surroundings for eight weeks. This would include a expedition in pressurized rovers to the crater Harpalus and the Mare Imbrium foothills. | https://en.wikipedia.org/wiki?curid=33783 |
12,227 | At this time, von Braun also worked out preliminary concepts for a human mission to Mars that used the space station as a staging point. His initial plans, published in "The Mars Project" (1952), had envisaged a fleet of 10 spacecraft (each with a mass of 3,720 metric tonnes), three of them uncrewed and each carrying one 200-tonne winged lander in addition to cargo, and nine crew vehicles transporting a total of 70 astronauts. The engineering and astronautical parameters of this gigantic mission were thoroughly calculated. A later project was much more modest, using only one purely orbital cargo ship and one crewed craft. In each case, the expedition would use minimum-energy Hohmann transfer orbits for its trips to Mars and back to Earth. | https://en.wikipedia.org/wiki?curid=33783 |
12,228 | Before technically formalizing his thoughts on human spaceflight to Mars, von Braun had written a science fiction novel on the subject, set in the year 1980. However, the manuscript was rejected by no fewer than 18 publishers. Von Braun later published small portions of this opus in magazines, to illustrate selected aspects of his Mars project popularizations. The complete manuscript, titled "", did not appear as a printed book until December 2006. | https://en.wikipedia.org/wiki?curid=33783 |
12,229 | In the hope that its involvement would bring about greater public interest in the future of the space program, von Braun also began working with Walt Disney and the Disney studios as a technical director, initially for three television films about space exploration. The initial broadcast devoted to space exploration was "Man in Space", which first went on air on 9 March 1955, drawing 40 million viewers. | https://en.wikipedia.org/wiki?curid=33783 |
12,230 | Later (in 1959) von Braun published a short booklet, condensed from episodes that had appeared in "This Week Magazine" before—describing his updated concept of the first crewed lunar landing. The scenario included only a single and relatively small spacecraft—a winged lander with a crew of only two experienced pilots who had already circumnavigated the Moon on an earlier mission. The brute-force direct ascent flight schedule used a rocket design with five sequential stages, loosely based on the Nova designs that were under discussion at this time. After a night launch from a Pacific island, the first three stages would bring the spacecraft (with the two remaining upper stages attached) to terrestrial escape velocity, with each burn creating an acceleration of 8–9 times standard gravity. Residual propellant in the third stage would be used for the deceleration intended to commence only a few hundred kilometers above the landing site in a crater near the lunar north pole. The fourth stage provided acceleration to lunar escape velocity, while the fifth stage would be responsible for a deceleration during return to the Earth to a residual speed that allows aerocapture of the spacecraft ending in a runway landing, much in the way of the Space Shuttle. One remarkable feature of this technical tale is that the engineer von Braun anticipated a medical phenomenon that would become apparent only years later: being a veteran astronaut with no history of serious adverse reactions to weightlessness offers no protection against becoming unexpectedly and violently spacesick. | https://en.wikipedia.org/wiki?curid=33783 |
12,231 | In the first half of his life, von Braun was a nonpracticing, "perfunctory" Lutheran, whose affiliation was nominal and not taken seriously. As described by Ernst Stuhlinger and Frederick I. Ordway III: "Throughout his younger years, von Braun did not show signs of religious devotion, or even an interest in things related to the church or to biblical teachings. In fact, he was known to his friends as a 'merry heathen' ("fröhlicher Heide")." Nevertheless, in 1945 he explained his decision to surrender to the Western Allies, rather than Russians, as being influenced by a desire to share rocket technology with people who followed the Bible. In 1946, he attended church in El Paso, El Paso County, Texas, and underwent a religious conversion to Evangelical Christianity. In an unnamed religious magazine he stated: | https://en.wikipedia.org/wiki?curid=33783 |
12,232 | On the motives behind this conversion, Michael J. Neufeld is of the opinion that he turned to religion "to pacify his own conscience", whereas University of Southampton scholar Kendrick Oliver said that von Braun was presumably moved "by a desire to find a new direction for his life after the moral chaos of his service for the Third Reich". Having "concluded one bad bargain with the Devil, perhaps now he felt a need to have God securely at his side". | https://en.wikipedia.org/wiki?curid=33783 |
12,233 | At a Gideons conference in 2004, W. Albert Wilson, a former pilot and NASA employee, claimed that he had talked with von Braun about the Christian faith while von Braun was working for NASA, and believed that conversation had been instrumental in von Braun's conversion. | https://en.wikipedia.org/wiki?curid=33783 |
12,234 | Later in life, he joined an Episcopal congregation, and became increasingly religious. He publicly spoke and wrote about the complementarity of science and religion, the afterlife of the soul, and his belief in God. He stated, "Through science man strives to learn more of the mysteries of creation. Through religion he seeks to know the Creator." He was interviewed by the Assemblies of God pastor C. M. Ward and stated that "The farther we probe into space, the greater my faith." In addition, he met privately with evangelist Billy Graham and with the civil rights leader Martin Luther King Jr. | https://en.wikipedia.org/wiki?curid=33783 |
12,235 | Von Braun developed and published his space station concept during the time of the Cold War when the U.S. government put the containment of the Soviet Union above everything else. The fact that his space station – if armed with missiles that could be easily adapted from those already available at this time – would give the United States space superiority in both orbital and orbit-to-ground warfare did not escape him. In his popular writings, von Braun elaborated on them in several of his books and articles, but he took care to qualify such military applications as "particularly dreadful". This much-less-peaceful aspect of von Braun's "drive for space" has been reviewed by Michael J. Neufeld from the Space History Division of the National Air and Space Museum in Washington. | https://en.wikipedia.org/wiki?curid=33783 |
12,236 | The U.S. Navy had been tasked with building a rocket to lift satellites into orbit, but the resulting Vanguard rocket launch system was unreliable. In 1957, with the launch of Sputnik 1, a belief grew within the United States that it lagged behind the Soviet Union in the emerging Space Race. American authorities then chose to use von Braun and his German team's experience with missiles to create an orbital launch vehicle. Von Braun had originally proposed such an idea in 1954, but it was denied at the time. | https://en.wikipedia.org/wiki?curid=33783 |
12,237 | NASA was established by law on 29 July 1958. One day later, the 50th Redstone rocket was successfully launched from Johnston Atoll in the south Pacific as part of Operation Hardtack I. Two years later, NASA opened the Marshall Space Flight Center at Redstone Arsenal in Huntsville, and the Army Ballistic Missile Agency (ABMA) development team led by von Braun was transferred to NASA. In a face-to-face meeting with Herb York at the Pentagon, von Braun made it clear he would go to NASA only if development of the Saturn were allowed to continue. Von Braun became the center's first director on 1 July 1960 and held the position until 27 January 1970. | https://en.wikipedia.org/wiki?curid=33783 |
12,238 | Von Braun's early years at NASA included a failed "four-inch flight" during which the first uncrewed Mercury-Redstone rocket only rose a few inches before settling back onto the launch pad. The launch failure was later determined to be the result of a "power plug with one prong shorter than the other because a worker filed it to make it fit". Because of the difference in the length of one prong, the launch system detected the difference in the power disconnection as a "cut-off signal to the engine". The system stopped the launch, and the incident created a "nadir of morale in Project Mercury". | https://en.wikipedia.org/wiki?curid=33783 |
12,239 | After the flight of Mercury-Redstone 2 in January 1961 experienced a string of problems, von Braun insisted on one more test before the Redstone could be deemed man-rated. His overly cautious nature brought about clashes with other people involved in the program, who argued that MR-2's technical issues were simple and had been resolved shortly after the flight. He overruled them, so a test mission involving a Redstone on a boilerplate capsule was flown successfully in March. Von Braun's stubbornness was blamed for the inability of the U.S. to launch a crewed space mission before the Soviet Union, which ended up putting the first man in space the following month. Three weeks later on 5 May, von Braun's team successfully launched Alan Shepard into space. He named his Mercury-Redstone 3 Freedom 7. | https://en.wikipedia.org/wiki?curid=33783 |
12,240 | The Marshall Center's first major program was the development of Saturn rockets to carry heavy payloads into and beyond Earth orbit. From this, the Apollo program for crewed Moon flights was developed. Von Braun initially pushed for a flight engineering concept that called for an Earth orbit rendezvous technique (the approach he had argued for building his space station), but in 1962, he converted to the lunar orbit rendezvous concept that was subsequently realized. During Apollo, he worked closely with former Peenemünde teammate, Kurt H. Debus, the first director of the Kennedy Space Center. His dream to help mankind set foot on the Moon became a reality on 16 July 1969, when a Marshall-developed Saturn V rocket launched the crew of Apollo 11 on its historic eight-day mission. Over the course of the program, Saturn V rockets enabled six teams of astronauts to reach the surface of the Moon. | https://en.wikipedia.org/wiki?curid=33783 |
12,241 | During the late 1960s, von Braun was instrumental in the development of the U.S. Space and Rocket Center in Huntsville. The desk from which he guided America's entry in the space race remains on display there. He also was instrumental in the launching of the experimental Applications Technology Satellite. He traveled to India and hoped that the program would be helpful for bringing a massive educational television project to help the poorest people in that country. | https://en.wikipedia.org/wiki?curid=33783 |
12,242 | During the local summer of 1966–67, von Braun participated in a field trip to Antarctica, organized for him and several other members of top NASA management. The goal of the field trip was to determine whether the experience gained by U.S. scientific and technological community during the exploration of Antarctic wastelands would be useful for the crewed exploration of space. Von Braun was mainly interested in management of the scientific effort on Antarctic research stations, logistics, habitation, and life support, and in using the barren Antarctic terrain like the glacial dry valleys to test the equipment that one day would be used to look for signs of life on Mars and other worlds. | https://en.wikipedia.org/wiki?curid=33783 |
12,243 | In an internal memo dated 16 January 1969, von Braun had confirmed to his staff that he would stay on as a center director at Huntsville to head the Apollo Applications Program. He referred to this time as a moment in his life when he felt the strong need to pray, stating "I certainly prayed a lot before and during the crucial Apollo flights". A few months later, on occasion of the first Moon landing, he publicly expressed his optimism that the Saturn V carrier system would continue to be developed, advocating human missions to Mars in the 1980s. | https://en.wikipedia.org/wiki?curid=33783 |
12,244 | Nonetheless, on 1 March 1970, von Braun and his family relocated to Washington, DC, when he was assigned the post of NASA's Deputy Associate Administrator for Planning at NASA Headquarters. After a series of conflicts associated with the truncation of the Apollo program, and facing severe budget constraints, von Braun retired from NASA on 26 May 1972. Not only had it become evident by this time that NASA and his visions for future U.S. space flight projects were incompatible, but also it was perhaps even more frustrating for him to see popular support for a continued presence of man in space wane dramatically once the goal to reach the Moon had been accomplished. | https://en.wikipedia.org/wiki?curid=33783 |
12,245 | Von Braun also developed the idea of a Space Camp that would train children in fields of science and space technologies, as well as help their mental development much the same way sports camps aim at improving physical development. | https://en.wikipedia.org/wiki?curid=33783 |
12,246 | After leaving NASA, von Braun moved to the Washington, D.C. area and became Vice President for Engineering and Development at the aerospace company Fairchild Industries in Germantown, Montgomery County, Maryland, on 1 July 1972. | https://en.wikipedia.org/wiki?curid=33783 |
12,247 | In 1973, during a routine physical examination, von Braun was diagnosed with kidney cancer, which could not be controlled with the medical techniques available at the time. | https://en.wikipedia.org/wiki?curid=33783 |
12,248 | Von Braun helped establish and promote the National Space Institute, a precursor of the present-day National Space Society, in 1975, and became its first president and chairman. In 1976, he became scientific consultant to , the CEO of OTRAG, and a member of the Daimler-Benz board of directors. However, his deteriorating health forced him to retire from Fairchild on 31 December 1976. When the 1975 National Medal of Science was awarded to him in early 1977, he was hospitalized, and unable to attend the White House ceremony. | https://en.wikipedia.org/wiki?curid=33783 |
12,249 | Von Braun's insistence on further tests after Mercury-Redstone 2 flew higher than planned has been identified as contributing to the Soviet Union's success in launching the first human in space. The Mercury-Redstone BD flight was successful, but took up the launch slot that might have put Alan Shepard into space three weeks ahead of Yuri Gagarin. His Soviet counterpart Sergei Korolev insisted on two successful flights with dogs before risking Gagarin's life on a crewed attempt. The second test flight took place one day after the Mercury-Redstone BD mission. | https://en.wikipedia.org/wiki?curid=33783 |
12,250 | Von Braun took a very conservative approach to engineering, designing with ample safety factors and redundant structure. This became a point of contention with other engineers, who struggled to keep vehicle weight down so that payload could be maximized. As noted above, his excessive caution likely led to the U.S. losing the race to put a man into space with the Soviets. Krafft Ehricke likened von Braun's approach to building the Brooklyn Bridge. Many at NASA headquarters jokingly referred to Marshall as the "Chicago Bridge and Iron Works", but acknowledged that the designs worked. The conservative approach paid off when a fifth engine was added to the Saturn C-4, producing the Saturn V. The C-4 design had a large crossbeam that could easily absorb the thrust of an additional engine. | https://en.wikipedia.org/wiki?curid=33783 |
12,251 | Von Braun did not indicate interest in politics or political philosophy during his onboarding working for the US army. He was primarily focused on his work in guided missiles for the purpose of furthering science and technology. According to FBI background checks, “any political activity he may have engaged in was a means to an end to provide him with the necessary freedom to conduct his experiments.” This included time spent in the Nazi party during World War 2. | https://en.wikipedia.org/wiki?curid=33783 |
12,252 | Von Braun had a charismatic personality and was known as a ladies' man. As a student in Berlin, he would often be seen in the evenings in the company of two girlfriends at once. He later had a succession of affairs within the secretarial and computer pool at Peenemünde. | https://en.wikipedia.org/wiki?curid=33783 |
12,253 | In January 1943, von Braun became engaged to Dorothee Brill, a physical education teacher in Berlin, and he sought permission to marry from the SS Race and Settlement Main Office. However, the engagement was broken due to his mother's opposition. Later in 1943, he had an affair with a French woman while in Paris preparing V-2 launch sites in northeastern France. She was imprisoned for collaboration after the war and became destitute. | https://en.wikipedia.org/wiki?curid=33783 |
12,254 | During his stay at Fort Bliss, von Braun proposed marriage to Maria Luise von Quistorp, his maternal first cousin, in a letter to his father. He married her in a Lutheran church in Landshut, Bavaria, on 1 March 1947, having received permission to go back to Germany and return with his bride. He was 35 and his new bride was 18. Shortly after, he converted to Evangelicalism. He returned to Manhattan on 26 March 1947, with his wife, father, and mother. On 8 December 1948, the von Brauns' first daughter together, Iris Careen, was born at Fort Bliss Army Hospital. The couple had two more children: Margrit Cécile, born in 1952, and Peter Constantine, born in 1960. | https://en.wikipedia.org/wiki?curid=33783 |
12,255 | In 1973, von Braun was diagnosed with kidney cancer during a routine medical examination. However, he continued to work unrestrained for a number of years. In January 1977, then very ill, he resigned from Fairchild Industries. Later in 1977, President Gerald R. Ford awarded him the country's highest science honor, the National Medal of Science in Engineering. He was, however, too ill to attend the White House ceremony. | https://en.wikipedia.org/wiki?curid=33783 |
12,256 | Von Braun died on 16 June 1977 of pancreatic cancer in Alexandria, Virginia, at age 65. He is buried on Valley Road at the Ivy Hill Cemetery. His gravestone cites Psalm 19:1: "The heavens declare the glory of God; and the firmament sheweth his handywork" (KJV). | https://en.wikipedia.org/wiki?curid=33783 |
12,257 | A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program. This contrasts with external components such as main memory and I/O circuitry, and specialized processors such as graphics processing units (GPUs). | https://en.wikipedia.org/wiki?curid=5218 |
12,258 | The form, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory), decoding and execution (of instructions) by directing the coordinated operations of the ALU, registers and other components. | https://en.wikipedia.org/wiki?curid=5218 |
12,259 | Most modern CPUs are implemented on integrated circuit (IC) microprocessors, with one or more CPUs on a single IC chip. Microprocessor chips with multiple CPUs are multi-core processors. The individual physical CPUs, processor cores, can also be multithreaded to create additional virtual or logical CPUs. | https://en.wikipedia.org/wiki?curid=5218 |
12,260 | An IC that contains a CPU may also contain memory, peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on a chip (SoC). | https://en.wikipedia.org/wiki?curid=5218 |
12,261 | Array processors or vector processors have multiple processors that operate in parallel, with no unit considered central. Virtual CPUs are an abstraction of dynamical aggregated computational resources. | https://en.wikipedia.org/wiki?curid=5218 |
12,262 | Early computers such as the ENIAC had to be physically rewired to perform different tasks, which caused these machines to be called "fixed-program computers". The "central processing unit" term has been in use since as early as 1955. Since the term "CPU" is generally defined as a device for software (computer program) execution, the earliest devices that could rightly be called CPUs came with the advent of the stored-program computer. | https://en.wikipedia.org/wiki?curid=5218 |
12,263 | The idea of a stored-program computer had been already present in the design of J. Presper Eckert and John William Mauchly's ENIAC, but was initially omitted so that it could be finished sooner. On June 30, 1945, before ENIAC was made, mathematician John von Neumann distributed the paper entitled "First Draft of a Report on the EDVAC". It was the outline of a stored-program computer that would eventually be completed in August 1949. EDVAC was designed to perform a certain number of instructions (or operations) of various types. Significantly, the programs written for EDVAC were to be stored in high-speed computer memory rather than specified by the physical wiring of the computer. This overcame a severe limitation of ENIAC, which was the considerable time and effort required to reconfigure the computer to perform a new task. With von Neumann's design, the program that EDVAC ran could be changed simply by changing the contents of the memory. EDVAC, was not the first stored-program computer, the Manchester Baby which was a small-scale experimental stored-program computer, ran its first program on 21 June 1948 and the Manchester Mark 1 ran its first program during the night of 16–17 June 1949. | https://en.wikipedia.org/wiki?curid=5218 |
12,264 | Early CPUs were custom designs used as part of a larger and sometimes distinctive computer. However, this method of designing custom CPUs for a particular application has largely given way to the development of multi-purpose processors produced in large quantities. This standardization began in the era of discrete transistor mainframes and minicomputers and has rapidly accelerated with the popularization of the integrated circuit (IC). The IC has allowed increasingly complex CPUs to be designed and manufactured to tolerances on the order of nanometers. Both the miniaturization and standardization of CPUs have increased the presence of digital devices in modern life far beyond the limited application of dedicated computing machines. Modern microprocessors appear in electronic devices ranging from automobiles to cellphones, and sometimes even in toys. | https://en.wikipedia.org/wiki?curid=5218 |
12,265 | While von Neumann is most often credited with the design of the stored-program computer because of his design of EDVAC, and the design became known as the von Neumann architecture, others before him, such as Konrad Zuse, had suggested and implemented similar ideas. The so-called Harvard architecture of the Harvard Mark I, which was completed before EDVAC, also used a stored-program design using punched paper tape rather than electronic memory. The key difference between the von Neumann and Harvard architectures is that the latter separates the storage and treatment of CPU instructions and data, while the former uses the same memory space for both. Most modern CPUs are primarily von Neumann in design, but CPUs with the Harvard architecture are seen as well, especially in embedded applications; for instance, the Atmel AVR microcontrollers are Harvard architecture processors. | https://en.wikipedia.org/wiki?curid=5218 |
12,266 | Relays and vacuum tubes (thermionic tubes) were commonly used as switching elements; a useful computer requires thousands or tens of thousands of switching devices. The overall speed of a system is dependent on the speed of the switches. Vacuum-tube computers such as EDVAC tended to average eight hours between failures, whereas relay computers like the (slower, but earlier) Harvard Mark I failed very rarely. In the end, tube-based CPUs became dominant because the significant speed advantages afforded generally outweighed the reliability problems. Most of these early synchronous CPUs ran at low clock rates compared to modern microelectronic designs. Clock signal frequencies ranging from 100 kHz to 4 MHz were very common at this time, limited largely by the speed of the switching devices they were built with. | https://en.wikipedia.org/wiki?curid=5218 |
12,267 | The design complexity of CPUs increased as various technologies facilitated building smaller and more reliable electronic devices. The first such improvement came with the advent of the transistor. Transistorized CPUs during the 1950s and 1960s no longer had to be built out of bulky, unreliable and fragile switching elements like vacuum tubes and relays. With this improvement, more complex and reliable CPUs were built onto one or several printed circuit boards containing discrete (individual) components. | https://en.wikipedia.org/wiki?curid=5218 |
12,268 | In 1964, IBM introduced its IBM System/360 computer architecture that was used in a series of computers capable of running the same programs with different speed and performance. This was significant at a time when most electronic computers were incompatible with one another, even those made by the same manufacturer. To facilitate this improvement, IBM used the concept of a microprogram (often called "microcode"), which still sees widespread usage in modern CPUs. The System/360 architecture was so popular that it dominated the mainframe computer market for decades and left a legacy that is still continued by similar modern computers like the IBM zSeries. In 1965, Digital Equipment Corporation (DEC) introduced another influential computer aimed at the scientific and research markets, the PDP-8. | https://en.wikipedia.org/wiki?curid=5218 |
12,269 | Transistor-based computers had several distinct advantages over their predecessors. Aside from facilitating increased reliability and lower power consumption, transistors also allowed CPUs to operate at much higher speeds because of the short switching time of a transistor in comparison to a tube or relay. The increased reliability and dramatically increased speed of the switching elements (which were almost exclusively transistors by this time); CPU clock rates in the tens of megahertz were easily obtained during this period. Additionally, while discrete transistor and IC CPUs were in heavy usage, new high-performance designs like single instruction, multiple data (SIMD) vector processors began to appear. These early experimental designs later gave rise to the era of specialized supercomputers like those made by Cray Inc and Fujitsu Ltd. | https://en.wikipedia.org/wiki?curid=5218 |
12,270 | During this period, a method of manufacturing many interconnected transistors in a compact space was developed. The integrated circuit (IC) allowed a large number of transistors to be manufactured on a single semiconductor-based die, or "chip". At first, only very basic non-specialized digital circuits such as NOR gates were miniaturized into ICs. CPUs based on these "building block" ICs are generally referred to as "small-scale integration" (SSI) devices. SSI ICs, such as the ones used in the Apollo Guidance Computer, usually contained up to a few dozen transistors. To build an entire CPU out of SSI ICs required thousands of individual chips, but still consumed much less space and power than earlier discrete transistor designs. | https://en.wikipedia.org/wiki?curid=5218 |
12,271 | IBM's System/370, follow-on to the System/360, used SSI ICs rather than Solid Logic Technology discrete-transistor modules. DEC's PDP-8/I and KI10 PDP-10 also switched from the individual transistors used by the PDP-8 and PDP-10 to SSI ICs, and their extremely popular PDP-11 line was originally built with SSI ICs but was eventually implemented with LSI components once these became practical. | https://en.wikipedia.org/wiki?curid=5218 |
12,272 | Lee Boysel published influential articles, including a 1967 "manifesto", which described how to build the equivalent of a 32-bit mainframe computer from a relatively small number of large-scale integration circuits (LSI). The only way to build LSI chips, which are chips with a hundred or more gates, was to build them using a metal–oxide–semiconductor (MOS) semiconductor manufacturing process (either PMOS logic, NMOS logic, or CMOS logic). However, some companies continued to build processors out of bipolar transistor–transistor logic (TTL) chips because bipolar junction transistors were faster than MOS chips up until the 1970s (a few companies such as Datapoint continued to build processors out of TTL chips until the early 1980s). In the 1960s, MOS ICs were slower and initially considered useful only in applications that required low power. Following the development of silicon-gate MOS technology by Federico Faggin at Fairchild Semiconductor in 1968, MOS ICs largely replaced bipolar TTL as the standard chip technology in the early 1970s. | https://en.wikipedia.org/wiki?curid=5218 |
12,273 | As the microelectronic technology advanced, an increasing number of transistors were placed on ICs, decreasing the number of individual ICs needed for a complete CPU. MSI and LSI ICs increased transistor counts to hundreds, and then thousands. By 1968, the number of ICs required to build a complete CPU had been reduced to 24 ICs of eight different types, with each IC containing roughly 1000 MOSFETs. In stark contrast with its SSI and MSI predecessors, the first LSI implementation of the PDP-11 contained a CPU composed of only four LSI integrated circuits. | https://en.wikipedia.org/wiki?curid=5218 |
12,274 | Since microprocessors were first introduced they have almost completely overtaken all other central processing unit implementation methods. The first commercially available microprocessor, made in 1971, was the Intel 4004, and the first widely used microprocessor, made in 1974, was the Intel 8080. Mainframe and minicomputer manufacturers of the time launched proprietary IC development programs to upgrade their older computer architectures, and eventually produced instruction set compatible microprocessors that were backward-compatible with their older hardware and software. Combined with the advent and eventual success of the ubiquitous personal computer, the term "CPU" is now applied almost exclusively to microprocessors. Several CPUs (denoted "cores") can be combined in a single processing chip. | https://en.wikipedia.org/wiki?curid=5218 |
12,275 | Previous generations of CPUs were implemented as discrete components and numerous small integrated circuits (ICs) on one or more circuit boards. Microprocessors, on the other hand, are CPUs manufactured on a very small number of ICs; usually just one. The overall smaller CPU size, as a result of being implemented on a single die, means faster switching time because of physical factors like decreased gate parasitic capacitance. This has allowed synchronous microprocessors to have clock rates ranging from tens of megahertz to several gigahertz. Additionally, the ability to construct exceedingly small transistors on an IC has increased the complexity and number of transistors in a single CPU many fold. This widely observed trend is described by Moore's law, which had proven to be a fairly accurate predictor of the growth of CPU (and other IC) complexity until 2016. | https://en.wikipedia.org/wiki?curid=5218 |
12,276 | While the complexity, size, construction and general form of CPUs have changed enormously since 1950, the basic design and function has not changed much at all. Almost all common CPUs today can be very accurately described as von Neumann stored-program machines. As Moore's law no longer holds, concerns have arisen about the limits of integrated circuit transistor technology. Extreme miniaturization of electronic gates is causing the effects of phenomena like electromigration and subthreshold leakage to become much more significant. These newer concerns are among the many factors causing researchers to investigate new methods of computing such as the quantum computer, as well as to expand the usage of parallelism and other methods that extend the usefulness of the classical von Neumann model. | https://en.wikipedia.org/wiki?curid=5218 |
12,277 | The fundamental operation of most CPUs, regardless of the physical form they take, is to execute a sequence of stored instructions that is called a program. The instructions to be executed are kept in some kind of computer memory. Nearly all CPUs follow the fetch, decode and execute steps in their operation, which are collectively known as the instruction cycle. | https://en.wikipedia.org/wiki?curid=5218 |
12,278 | After the execution of an instruction, the entire process repeats, with the next instruction cycle normally fetching the next-in-sequence instruction because of the incremented value in the program counter. If a jump instruction was executed, the program counter will be modified to contain the address of the instruction that was jumped to and program execution continues normally. In more complex CPUs, multiple instructions can be fetched, decoded and executed simultaneously. This section describes what is generally referred to as the "classic RISC pipeline", which is quite common among the simple CPUs used in many electronic devices (often called microcontrollers). It largely ignores the important role of CPU cache, and therefore the access stage of the pipeline. | https://en.wikipedia.org/wiki?curid=5218 |
12,279 | Some instructions manipulate the program counter rather than producing result data directly; such instructions are generally called "jumps" and facilitate program behavior like loops, conditional program execution (through the use of a conditional jump), and existence of functions. In some processors, some other instructions change the state of bits in a "flags" register. These flags can be used to influence how a program behaves, since they often indicate the outcome of various operations. For example, in such processors a "compare" instruction evaluates two values and sets or clears bits in the flags register to indicate which one is greater or whether they are equal; one of these flags could then be used by a later jump instruction to determine program flow. | https://en.wikipedia.org/wiki?curid=5218 |
12,280 | Fetch involves retrieving an instruction (which is represented by a number or sequence of numbers) from program memory. The instruction's location (address) in program memory is determined by the program counter (PC; called the "instruction pointer" in Intel x86 microprocessors), which stores a number that identifies the address of the next instruction to be fetched. After an instruction is fetched, the PC is incremented by the length of the instruction so that it will contain the address of the next instruction in the sequence. Often, the instruction to be fetched must be retrieved from relatively slow memory, causing the CPU to stall while waiting for the instruction to be returned. This issue is largely addressed in modern processors by caches and pipeline architectures (see below). | https://en.wikipedia.org/wiki?curid=5218 |
12,281 | The instruction that the CPU fetches from memory determines what the CPU will do. In the decode step, performed by binary decoder circuitry known as the "instruction decoder", the instruction is converted into signals that control other parts of the CPU. | https://en.wikipedia.org/wiki?curid=5218 |
12,282 | The way in which the instruction is interpreted is defined by the CPU's instruction set architecture (ISA). Often, one group of bits (that is, a "field") within the instruction, called the opcode, indicates which operation is to be performed, while the remaining fields usually provide supplemental information required for the operation, such as the operands. Those operands may be specified as a constant value (called an immediate value), or as the location of a value that may be a processor register or a memory address, as determined by some addressing mode. | https://en.wikipedia.org/wiki?curid=5218 |
12,283 | In some CPU designs the instruction decoder is implemented as a hardwired, unchangeable binary decoder circuit. In others, a microprogram is used to translate instructions into sets of CPU configuration signals that are applied sequentially over multiple clock pulses. In some cases the memory that stores the microprogram is rewritable, making it possible to change the way in which the CPU decodes instructions. | https://en.wikipedia.org/wiki?curid=5218 |
12,284 | After the fetch and decode steps, the execute step is performed. Depending on the CPU architecture, this may consist of a single action or a sequence of actions. During each action, control signals electrically enable or disable various parts of the CPU so they can perform all or part of the desired operation. The action is then completed, typically in response to a clock pulse. Very often the results are written to an internal CPU register for quick access by subsequent instructions. In other cases results may be written to slower, but less expensive and higher capacity main memory. | https://en.wikipedia.org/wiki?curid=5218 |
12,285 | For example, if an addition instruction is to be executed, registers containing operands (numbers to be summed) are activated, as are the parts of the arithmetic logic unit (ALU) that perform addition. When the clock pulse occurs, the operands flow from the source registers into the ALU, and the sum appears at its output. On subsequent clock pulses, other components are enabled (and disabled) to move the output (the sum of the operation) to storage (e.g., a register or memory). If the resulting sum is too large (i.e., it is larger than the ALU's output word size), an arithmetic overflow flag will be set, influencing the next operation. | https://en.wikipedia.org/wiki?curid=5218 |
12,286 | Hardwired into a CPU's circuitry is a set of basic operations it can perform, called an instruction set. Such operations may involve, for example, adding or subtracting two numbers, comparing two numbers, or jumping to a different part of a program. Each instruction is represented by a unique combination of bits, known as the machine language opcode. While processing an instruction, the CPU decodes the opcode (via a binary decoder) into control signals, which orchestrate the behavior of the CPU. A complete machine language instruction consists of an opcode and, in many cases, additional bits that specify arguments for the operation (for example, the numbers to be summed in the case of an addition operation). Going up the complexity scale, a machine language program is a collection of machine language instructions that the CPU executes. | https://en.wikipedia.org/wiki?curid=5218 |
12,287 | The actual mathematical operation for each instruction is performed by a combinational logic circuit within the CPU's processor known as the arithmetic–logic unit or ALU. In general, a CPU executes an instruction by fetching it from memory, using its ALU to perform an operation, and then storing the result to memory. Beside the instructions for integer mathematics and logic operations, various other machine instructions exist, such as those for loading data from memory and storing it back, branching operations, and mathematical operations on floating-point numbers performed by the CPU's floating-point unit (FPU). | https://en.wikipedia.org/wiki?curid=5218 |
12,288 | The control unit (CU) is a component of the CPU that directs the operation of the processor. It tells the computer's memory, arithmetic and logic unit and input and output devices how to respond to the instructions that have been sent to the processor. | https://en.wikipedia.org/wiki?curid=5218 |
12,289 | It directs the operation of the other units by providing timing and control signals. Most computer resources are managed by the CU. It directs the flow of data between the CPU and the other devices. John von Neumann included the control unit as part of the von Neumann architecture. In modern computer designs, the control unit is typically an internal part of the CPU with its overall role and operation unchanged since its introduction. | https://en.wikipedia.org/wiki?curid=5218 |
12,290 | The arithmetic logic unit (ALU) is a digital circuit within the processor that performs integer arithmetic and bitwise logic operations. The inputs to the ALU are the data words to be operated on (called operands), status information from previous operations, and a code from the control unit indicating which operation to perform. Depending on the instruction being executed, the operands may come from internal CPU registers, external memory, or constants generated by the ALU itself. | https://en.wikipedia.org/wiki?curid=5218 |
12,291 | When all input signals have settled and propagated through the ALU circuitry, the result of the performed operation appears at the ALU's outputs. The result consists of both a data word, which may be stored in a register or memory, and status information that is typically stored in a special, internal CPU register reserved for this purpose. | https://en.wikipedia.org/wiki?curid=5218 |
12,292 | Address generation unit (AGU), sometimes also called address computation unit (ACU), is an execution unit inside the CPU that calculates addresses used by the CPU to access main memory. By having address calculations handled by separate circuitry that operates in parallel with the rest of the CPU, the number of CPU cycles required for executing various machine instructions can be reduced, bringing performance improvements. | https://en.wikipedia.org/wiki?curid=5218 |
12,293 | While performing various operations, CPUs need to calculate memory addresses required for fetching data from the memory; for example, in-memory positions of array elements must be calculated before the CPU can fetch the data from actual memory locations. Those address-generation calculations involve different integer arithmetic operations, such as addition, subtraction, modulo operations, or bit shifts. Often, calculating a memory address involves more than one general-purpose machine instruction, which do not necessarily decode and execute quickly. By incorporating an AGU into a CPU design, together with introducing specialized instructions that use the AGU, various address-generation calculations can be offloaded from the rest of the CPU, and can often be executed quickly in a single CPU cycle. | https://en.wikipedia.org/wiki?curid=5218 |
12,294 | Capabilities of an AGU depend on a particular CPU and its architecture. Thus, some AGUs implement and expose more address-calculation operations, while some also include more advanced specialized instructions that can operate on multiple operands at a time. Some CPU architectures include multiple AGUs so more than one address-calculation operation can be executed simultaneously, which brings further performance improvements due to the superscalar nature of advanced CPU designs. For example, Intel incorporates multiple AGUs into its Sandy Bridge and Haswell microarchitectures, which increase bandwidth of the CPU memory subsystem by allowing multiple memory-access instructions to be executed in parallel. | https://en.wikipedia.org/wiki?curid=5218 |
12,295 | Many microprocessors (in smartphones and desktop, laptop, server computers) have a memory management unit, translating logical addresses into physical RAM addresses, providing memory protection and paging abilities, useful for virtual memory. Simpler processors, especially microcontrollers, usually don't include an MMU. | https://en.wikipedia.org/wiki?curid=5218 |
12,296 | A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have different independent caches, including instruction and data caches, where the data cache is usually organized as a hierarchy of more cache levels (L1, L2, L3, L4, etc.). | https://en.wikipedia.org/wiki?curid=5218 |
12,297 | All modern (fast) CPUs (with few specialized exceptions) have multiple levels of CPU caches. The first CPUs that used a cache had only one level of cache; unlike later level 1 caches, it was not split into L1d (for data) and L1i (for instructions). Almost all current CPUs with caches have a split L1 cache. They also have L2 caches and, for larger processors, L3 caches as well. The L2 cache is usually not split and acts as a common repository for the already split L1 cache. Every core of a multi-core processor has a dedicated L2 cache and is usually not shared between the cores. The L3 cache, and higher-level caches, are shared between the cores and are not split. An L4 cache is currently uncommon, and is generally on dynamic random-access memory (DRAM), rather than on static random-access memory (SRAM), on a separate die or chip. That was also the case historically with L1, while bigger chips have allowed integration of it and generally all cache levels, with the possible exception of the last level. Each extra level of cache tends to be bigger and be optimized differently. | https://en.wikipedia.org/wiki?curid=5218 |
12,298 | Other types of caches exist (that are not counted towards the "cache size" of the most important caches mentioned above), such as the translation lookaside buffer (TLB) that is part of the memory management unit (MMU) that most CPUs have. | https://en.wikipedia.org/wiki?curid=5218 |
12,299 | Caches are generally sized in powers of two: 2, 8, 16 etc. KiB or MiB (for larger non-L1) sizes, although the IBM z13 has a 96 KiB L1 instruction cache. | https://en.wikipedia.org/wiki?curid=5218 |
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