The first DDA built was the Magnetic Drum Digital Differential Analyzer of 1950.
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Ridenour led the development of airborne microwave radar nicknamed "Micky" which allowed bombing through clouds. Along with Gilbert W. King, Edwin L. Hughes, and George W. Brown, Ridenour patented an information storage system which combined optical disk storage of large capacity and a magnetic drum memory of low capacity. The write-once-read-many optical disk memory would be updated monthly, and recently changed data is held on the re-writable magnetic drum memory.
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Each word could hold either one 40-bit number or two 20-bit program instructions. The main store initially consisted of two double- density Williams tubes, each holding two arrays of 32 x 40-bit words – known as pages – backed up by a magnetic drum capable of storing an additional 32 pages. The capacity was increased in the Final Specification version to eight pages of main store on four Williams tubes and 128 magnetic drum pages of backing store.
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London: Computer Conservation Society. was a British electrical engineer, physicist and computer scientist, who was an early developer of the magnetic drum memory for computers. He is known for Booth's multiplication algorithm.
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The Mark IV used magnetic drum and had 200 registers of ferrite magnetic core memory (one of the first computers to do so). It separated the storage of data and instructions in what is known as the Harvard architecture.
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EDVAC received a number of upgrades including punch-card I/O in 1954, extra memory in slower magnetic drum form in 1955, and a floating-point arithmetic unit in 1958. EDVAC ran until 1962 when it was replaced by BRLESC.
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It also had read-only semiconductor diode memory for programs. Data input was from punched cards or magnetic tape. Data output was to magnetic tape, punched cards or wide printer. The last version of Strela used a 4096-word magnetic drum, rotating at 6000 rpm.
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The Datatron has a word size of ten decimal digits plus a sign. Character data occupies two digits per character. A magnetic drum is used for memory. The drum rotates at 3570 rotations per minute (RPM) and stores 400010 words on 20 tracks (called bands).
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The time announcements were made by playing short, recorded phrases or words in the correct sequence. In an interview with Manchester Radio in 1957 Miss Cain said: In 1963, the original device was replaced by more modern recording technology using a magnetic drum, similar to the Audichron technology used in the United States. The company that manufactured the rotating magnetic drum part of the Speaking Clock was Roberts & Armstrong (Engineers) Ltd of North Wembley. They took on the licence from the British Post Office to manufacture complete clocks for the telecommunications authorities of Denmark, Sweden and the Republic of Ireland, and a third (spare) clock for the British Post Office.
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It became operational in 1962, two years later than expected. ILLIAC II had 8192 words of core memory, backed up by 65,536 words of storage on magnetic drums. The core memory access time was 1.8 to 2 µs. The magnetic drum access time was 7 µs.
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In May, 1952, CEC pre-announced the "CEC 30-201" computer, a vacuum tube computer with a magnetic drum memory. That same year CEC reorganized computer development into a separate Computer Division. In 1954 the division was spun off into a separate public company named ElectroData.
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When the decision was made to use magnetic drum memory (MAD) for the DIDA, the name was lengthened to MADDIDA (pronounced "Mad Ida").Reilly 2003, p. 163. In his design for MADDIDA, Steele was influenced by the analog computer invented in 1927 by Vannevar Bush, which had digital components.
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It had the first magnetic core of 1096 words of 36 bits. The magnetic drum storage had a capacity of 16,384 words, and the clock speed was 500K. Input/output was teletype paper tape. When NACA became NASA in 1958, a series of improvements was begun to improve functionality and reliability.
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Billing worked at the Aerodynamic Research Institute in Göttingen, where he developed a magnetic drum memory. According to Billing's memoirs, published by Genscher, Düsseldorf (1997), there was a meeting between Alan Turing and Konrad Zuse. It took place in Göttingen in 1947. The interrogation had the form of a colloquium.
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The programmable program memory had a maximum size of 4096 words.Zuse KG: Einführung in die Arbeitsweise der Zentraleinheit des Datenverarbeitungssytems Zuse Z 25 (Ausgabe April 1963). For mass storage there was a drum memory available as well as a magnetic tape memory. The magnetic drum had a storage capacity of 17664 Z25 words.
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This version used a magnetic drum in place of the disk, its increased performance allowing more data to be stored before performance became an issue. This version used 6-bit words for locations instead of the prototype's 4-bit words, increasing resolution and allowing support for 2,000 inch documents instead of 800.First, pg.
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This scheme allows up to 26,000 user accounts. During execution, user programs are swapped to a fixed head drive — physically a disk, but operating like a magnetic drum. When not executing, user programs are stored on moving- head cartridge- or pack-loaded disk storage. Privileged users can also store programs on the much-faster drum.
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Storage was provided by a magnetic drum memory holding 8K words; accumulators were also implemented as recirculating drum tracks in a manner similar to that used in the Bendix G-15. Peripherals included paper tape reader and punch, and a teleprinter. In 1967, six Zebra computers were in use in UK universities and technical colleges.
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In 1952, Parker sold ERA to Remington Rand. Although Rand kept the ERA team together and developing new products, it was most interested in ERA's magnetic drum memory systems. Rand soon merged with Sperry Corporation to become Sperry Rand. In the process of merging the companies, the ERA division was folded into Sperry's UNIVAC division.
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The G-15 has 180 vacuum tube packs and 300 germanium diodes."The Bendix G-15" It has a total of about 450 tubes (mostly dual triodes). Its magnetic drum memory holds 2,160 words of twenty-nine bits. Average memory access time is 14.5 milliseconds, but its instruction addressing architecture can reduce this dramatically for well-written programs.
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Part of MADDIDA at Computer History Museum The MADDIDA (MAgnetic Drum DIgital Differential Analyzer) was a special-purpose digital computer used for solving systems of ordinary differential equations.Reilly 2003, p. 164. It was the first computer to represent bits using voltage levels and whose entire logic was specified in Boolean algebra."Annals of the History of Computing" 1988, p.
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That distinction goes to the Harwell CADET of 1955, built by the electronics division of the Atomic Energy Research Establishment at Harwell. The design featured a 64-kilobyte magnetic drum memory store with multiple moving heads that had been designed at the National Physical Laboratory, UK. By 1953 this team had transistor circuits operating to read and write on a smaller magnetic drum from the Royal Radar Establishment. The machine used a low clock speed of only 58 kHz to avoid having to use any valves to generate the clock waveforms. CADET used 324 point-contact transistors provided by the UK company Standard Telephones and Cables; 76 junction transistors were used for the first stage amplifiers for data read from the drum, since point-contact transistors were too noisy.
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WEIZAC was an asynchronous computer operating on 40-bit words. Instructions consisted of twenty bits: an eight-bit instruction code and twelve bits for addressing. Punched paper tape was used for I/O, and later, in 1958, magnetic tape. The memory was initially a magnetic drum containing 1,024 words which was later replaced with a much faster 4,096 word magnetic-core memory module.
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In 1987, Heinz Billing received the Konrad Zuse Medal for the invention of magnetic drum storage. In 2015 he received the Order of Merit of the Federal Republic of Germany. In 1993, the annual Heinz Billing prize for "outstanding contributions to computational science" was established by the Max Planck Society in his honor, with a prize amount of 5000 Euro.
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The computer was built to fulfill the needs of Moscow State University. It was manufactured at the Kazan Mathematical plant. Fifty computers were built from 1959 until 1965, when production was halted. The characteristic operating memory consisted of 81 words of memory, each word composed of 18 trits (ternary digits) with additional 1944 words on magnetic drum (total of about 7 KB).
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The UNIVAC Solid State was a 2-address, bi-quinary coded decimal computer using signed 10-digit words. Main memory storage was provided by a 5000-word magnetic drum spinning at 17,667 RPM in a helium atmosphere. For efficiency, programmers had to take into account drum latency, the time required for a specific data item, once written, to rotate to where it could be read.
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1, National Archives of Canada. The prototype machine used 3,800 vacuum tubes and stored data for up to 500 objects on a magnetic drum. The system could supply data for 64 targets with a resolution of 40 by 40 yards over an 80 by 80 nautical mile grid. In a production setting, only one ship in a task force would carry the DATAR computer.
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In 1928, Fritz Pfleumer developed the first magnetic tape recorder. Early magnetic storage devices were designed to record analog audio signals. Computers and now most audio and video magnetic storage devices record digital data. In old computers, magnetic storage was also used for primary storage in a form of magnetic drum, or core memory, core rope memory, thin film memory, twistor memory or bubble memory.
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Gösta Neovius and Olle Karlqvist were responsible for architecture and instruction set. It was closely modeled on the IAS machine for which the design team had retrieved drawings during a scholarship to Institute for Advanced Study (IAS) and Massachusetts Institute of Technology, U.S. During the development of the BESK magnetic drum memory, Olle Karlqvist discovered a magnetic phenomenon, which has been called the Karlqvist gap.
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It was small enough to easily fit in an office; it weighed about . It was designed to be used in a normal office, without any special electrical or air conditioning requirements. It used vacuum tubes, a magnetic drum, and punched paper tape readers and punchers. The input was from a keyboard and output was to an IBM electric typewriter, at eighteen characters per second.
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Retrieved from Connected-Earth.com December 18, 2013. The images were captured by the Picturephone's compact Vidicon camera and then transferred to a storage tube or magnetic drum for transmission over regular phone lines at two-second intervals to the receiving unit, which displayed them on a small cathode-ray television tube. AT&T; had earlier promoted its experimental video for telephone service at the 1939 New York World's Fair.
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Zuse's workshop at Neukirchen (photograph taken in January 2010) Magnetic drum storage inside a Z31 (which was first displayed in 1963). Zuse founded one of the earliest computer companies: the Zuse-Ingenieurbüro Hopferau. Capital was raised in 1946 through ETH Zurich and an IBM option on Zuse's patents. In 1949, Zuse founded another company, Zuse KG in Haunetal-Neukirchen; in 1957 the company's head office moved to Bad Hersfeld.
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The first task of the electronic control was to detect when a new call arrived. For this purpose each subscriber's line termination was examined for a period of 280 microseconds every 224 milliseconds, a process known as scanning. Junctions were scanned at eight times this rate. The scanning was carried out by a magnetic drum, each track of which is divided into 100 sections or words, one for each line.
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It was marketed as the IBM 701 in 1952. There were 18 model 701 machines built (in addition to the Engineering development machine). In 1953 Hurd convinced IBM management to develop what became the IBM 650 Magnetic Drum Data Processing Machine. Although the UNIVAC I (and Ferranti Mark 1 in England) had been introduced earlier than any IBM computer, its high price (while IBM offered monthly leases) limited sales.
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The MADDIDA had 44 integrators implemented using a magnetic drum with six storage tracks. The interconnections of the integrators were specified by writing an appropriate pattern of bits onto one of the tracks.Computer History Museum, Artifact Catalog In contrast to the prior ENIAC and UNIVAC I computers, which used electrical pulses to represent bits, the MADDIDA was the first computer to represent bits using voltage levels.Reilly 2003, p. 164.
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The system used electrostatic storage, consisting of 36 Williams tubes with a capacity of 1024 bits each, giving a total random access memory of 1024 words of 36 bits each. Each of the 36 Williams tubes was five inches in diameter. A magnetic drum memory provided 16,384 words. Both the electrostatic and drum memories were directly addressable: addresses 0 through 01777 (Octal) were in electrostatic memory and 040000 through 077777 (Octal) were on the drum.
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Up to two IBM 733 Magnetic Drum units, each with 8,192 words of memory, could be attached independently from the Data Synchronizers. The 709 could initially load programs (boot) from card, tape or drum. The IBM 738 Magnetic Core Storage used on 709 was also a milestone of hybrid technology. Although the core array drivers are all vacuum tube, the read sense amplifiers were a very early use of transistors in computing.
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The next computer that von Neumann designed was the IAS machine at the Institute for Advanced Study in Princeton, New Jersey. He arranged its financing, and the components were designed and built at the RCA Research Laboratory nearby. John von Neumann recommended that the IBM 701, nicknamed the defense computer, include a magnetic drum. It was a faster version of the IAS machine and formed the basis for the commercially successful IBM 704.
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In June 1952, Daniel Slotnick began working on the IAS machine at the Institute for Advanced Study (IAS) at Princeton University. The IAS machine featured a bit-parallel math unit that operated on 40-bit words. Originally equipped with Williams tube memory, a magnetic drum from Engineering Research Associates was later added. This drum had 80 tracks so two words could be read at a time, and each track stored 1,024 bits.
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There were eight pages of Williams cathode ray tube (CRT) random access memory as the fast primary store, and 512 pages of the secondary store on a magnetic drum. Each page consisted of thirty-two 40-bit words, which appeared as sixty-four 20-bit lines on the CRTs. The programmer had to control all transfers between electronic and magnetic storage, and the transfers were slow and had to be reduced to a minimum.
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The DASK was a vacuum tube machine based on the Swedish BESK design. As described in 1956, it contained 2500 vacuum tubes, 1500 solid-state elements, and required a three-phase power supply of at least 15 kW. Fast storage was 1024 40-bit words of magnetic core memory (cycle time 5µs), directly addressable as 1024 full or 2048 half-words. This was complemented by an additional 8192 words of backing store on magnetic drum (3000 rpm).
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Routing information would be placed on the magnetic drum, which could store thousands of routes and could be easily changed on demand. Levy, however, was interested in using an optical memory system being developed at IBM by a team including Louis Ridenour (see Automatic Language Translator for details) for storage of the routing information. Turnbull overruled Levy, and on 10 August 1954 he signed a contract with Ferranti for the Electronic Information Handling System using a drum memory.Vardalas, pg.
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He continued his work on the Mark III and the Harvard Mark IV. The Mark III used some electronic components and the Mark IV was all-electronic. The Mark III and Mark IV used magnetic drum memory and the Mark IV also had magnetic core memory. Aiken accumulated honorary degrees at the University of Wisconsin, Wayne State and Technische Hochschule, Darmstadt. He was elected a Fellow of the American Academy of Arts and Sciences in 1947.
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The work was dubbed "Project Teepee" (for "Thaler's Project"). Their first experimental system, MUSIC (Multiple Storage, Integration, and Correlation), became operational in 1955 and was able to detect rocket launches away at Cape Canaveral, and nuclear explosions in Nevada at . A greatly improved system, a testbed for an operational radar, was built in 1961 as MADRE (Magnetic-Drum Radar Equipment) at Chesapeake Bay. It detected aircraft as far as using as little as 50 kW of broadcast energy.
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The Versatran robot had been developed by American Machine and Foundry. A year later a hydraulic robot design by Unimation was put into production by Kawasaki Heavy Industries. Marvin Minsky created the Tentacle Arm in 1968; the arm was computer-controlled and its 12 joints were powered by hydraulics. In 1969 Mechanical Engineering student Victor Scheinman created the Stanford Arm, recognized as the first electronic computer-controlled robotic arm because the Unimate's instructions were stored on a magnetic drum.
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Harwell CADET Computer The Harwell CADET was the first fully transistorised computer in Europe, and may have been the first fully transistorised computer in the world. The electronics division of the Atomic Energy Research Establishment at Harwell, UK built the Harwell Dekatron Computer in 1951, which was an automatic calculator where the decimal arithmetic and memory were electronic, although other functions were performed by relays. By 1953, it was evident that this did not meet AERE's computing needs, and AERE director Sir John Cockcroft encouraged them to design and build a computer using transistors throughout. E. H. Cooke-Yarborough based the design around a 64-kilobyte (65,536 bytes) magnetic drum memory store with multiple moving heads that had been designed at the National Physical Laboratory, UK. By 1953 his team had transistor circuits operating to read and write on a smaller magnetic drum from the Royal Radar Establishment. The machine used a low clock speed of only 58 kHz to avoid having to use any valves to generate the clock waveforms.
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The G-15 was inspired by the Automatic Computing Engine (ACE). It is a serial-architecture machine, in which the main memory is a magnetic drum. It uses the drum as a recirculating delay line memory, in contrast to the analog delay line implementation in other serial designs. Each track has a set of read and write heads; as soon as a bit was read off a track, it is re-written on the same track a certain distance away.
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When the decision was made to use MAgnetic Drum memory (MAD) for the DIDA, the name was lengthened to MADDIDA (pronounced "Mad Ida"). Steele drew influence from the analog computer invented in 1927 by Vannevar Bush, which had digital components. Another influence to the MADDIDA's design was Lord Kelvin's Tide Predicting Machine, an analog computer completed in 1873. Steele hired Donald Eckdahl, Hrant (Harold) Sarkinssian, and Richard Sprague to work on the MADIDDA's germanium diode logic circuits and also to do magnetic recording.
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It contained 1727 vacuum tubes and 853 transistors and had a memory of 4096 72-bit words. BRLESC employed punched cards, magnetic tape, and a magnetic drum as input-output devices, which could be operated simultaneously. It was capable of five million (bitwise) operations per second. A fixed-point addition took 5 microseconds, a floating-point addition took 5 to 10 microseconds, a multiplication (fixed- or floating-point) took 25 microseconds, and a division (fixed- or floating-point) took 65 microseconds.
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The GE/PAC 4000 computer systems are an obsolete line of computers manufactured by General Electric in Phoenix, Arizona beginning in the 1960s. PAC is short for Process Automation Computer, indicating the intended use of the systems for process control. All 4000 systems are 24-bit, using fixed- point binary data, with between 1020 and 65,536 words of magnetic core memory, and a magnetic drum memory with 8192 to 262,144 word capacity. The CPU logic is implemented with discrete transistors.
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The CAB500 was a French transistor-based drum computer, designed at SEA around 1957 by Alice Recoque. The computer had an incremental compiler for a language, PAF (Programmation Automatique des Formules) similar to Fortran, designed by Dimitri Starynkevitch in 1957-1959. CAB 500's first model was delivered in February, 1961, and more than a hundred exemplars were built. It had a magnetic drum memory of rotating at and could invert a square matrix of order 25 in half an hour.
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In 1956, the company received a contract from the Canadian Post Office to develop an electronic mail sorting system, which they delivered later that year. The system used a hard-wired transistorized computer that stored a table of postal codes on a magnetic drum. Operators were presented with envelopes and typed in the postal code, which their typewriter printed onto the envelope as a bar code in fluorescent ink. The sorting system would then read the bar code and automatically route it sort it.
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The second bank was used for user programs. Although this was a relatively large amount of memory for the era, the system was so heavily used that the 16k word user store was not enough, and it was backed up with a magnetic drum for paging support. The drum was driven by external hardware and did not require attention from the main processor. In order to support multiple user programs, the PDP-6 hardware was modified to examine bit-20 of any address reference.
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The concept, proposed in 1958, pioneered Emitter-coupled logic (ECL) circuitry, pipelining, and transistor memory with a design goal of 100x speedup compared to ILLIAC I. ILLIAC II had 8192 words of core memory, backed up by 65,536 words of storage on magnetic drums. The core memory access time was 1.8 to 2 µs. The magnetic drum access time was 8.5ms. A "fast buffer" was also provided for storage of short loops and intermediate results (similar in concept to what is now called cache).
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The Binson Echorec is an echo machine produced by Italian (Milan) company Binson, an early manufacturer of such devices. Unlike most other analog echo machines, they used an analog magnetic drum recorder instead of a tape loop. After using Meazzi Echomatic machines successfully to establish his signature sound, Hank Marvin of The Shadows began using Binson echoes. He used various Binson units on record and stage for much of the mid-to-late 1960s, in conjunction with Vox AC30 amplifiers and Burns London guitars.
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In purely numeric mode, the tape reading and writing was performed at 240,000 digits per second. All tape drives were “industry” (meaning IBM) compatible and contained automatic error-checking systems. Either 7 or 9 channel tape code could be used and tapes could be written in the forward direction and read in both forward and reverse directions. # Mass storage was available in the form of both magnetic drum and magnetic disc with an interchangeable disc-pack capacity of 7.25 MB at a data interchange rate of 156 kbit/s.
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Support for the 650 and its component units was withdrawn in 1969. The 650 was a two-address, bi-quinary coded decimal computer (both data and addresses were decimal), with memory on a rotating magnetic drum. Character support was provided by the input/output units converting punched card alphabetical and special character encodings to/from a two-digit decimal code. The 650 was marketed to business, scientific and engineering users as well as to users of punched card machines who were upgrading from calculating punches, such as the IBM 604, to computers.
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He needed punched card input and output technologies and struck a deal with BTM,BTM marketed Hollerith equipment in the UK as well as manufacturing its own machines whereby they supplied him with these in return for their copying the machine that he was developing, including its magnetic drum memory. In March 1951, BTM's Dr Raymond 'Dickie' Bird with Bill Davis and Dickie Cox were dispatched to Fenny Compton in Warwickshire where Booth lived and where, in a rotting barn, he was developing the prototype of his machine.
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The Karlqvist gap or Karlqvist Field is an electromagnetic phenomenon discovered in 1953 by the Swedish engineer Olle Karlqvist (1922-1976) which is important in magnetic storage for computers. (HTML 1 kB) Karlqvist discovered the phenomenon while designing a ferromagnetic surface layer to the magnetic drum memory for the BESK computer. (HTML 3 kB) When designing a magnetic memory store, the ferromagnetic layer must be studied to determine the variation of the magnetic field with permeability, air gap, layer thickness and other influencing factors. The problem is non-linear and extremely difficult to solve.
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In 1946 American Airlines decided to tackle this problem through automation, introducing the Reservisor, a simple electromechanical computer based on telephone switching systems. Newer versions of the Reservisor included magnetic drum systems for storing flight information further into the future. The ultimate version of the system, the Magnetronic Reservisor, was installed in 1956 and could store data for 2,000 flights a day up to one month into the future. Reservisors were later sold to a number of airlines, as well as Sheraton for hotel bookings, and Goodyear for inventory control.
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Secondary storage was provided in the form of a 512-page magnetic drum, storing two pages per track, with about 30 milliseconds revolution time. The drum provided eight times the storage of the original designed at Manchester. The instructions, like the Manchester machine, used a single address format in which operands were modified and left in the accumulator. There were about fifty instructions in total. The basic cycle time was 1.2 milliseconds, and a multiplication could be completed in the new parallel unit in about 2.16 milliseconds (about 5 times faster than the original).
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This basic concept would work for a long-range radar as well, but had the problem that a delay line has to be mechanically sized to the pulse repetition frequency of the radar, or PRF. For long-range use, the PRF was very long to start, and deliberately changed in order to make different ranges come into view. For this role, the delay line was not usable, and the magnetic drum, recently introduced, provided a convenient and easily controlled variable- delay system. Another early shortwave OTH system was built in Australia in the early 1960s.
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This eventually led to the development of the AN/TRC-97 built by RCA. The TRC-97 provided data, voice and teletype connectivity for MTDS and would grow to become the backbone of USMC and USAF long haul communications for years to come. Early in the design phase of MTDS, it was decided to use magnetic drum memory computers. Memory drums were used as the digital storage elements and system clock pulse generators in the Central Computer Group and each of the Radar and Identification Data Processors (RIDP).
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Programmer, Irma Lewis, at the console of the Alwac III computer, 1959. The ALWAC III-E was an early commercial vacuum tube computer employing a rotating magnetic drum main storage unit, operational in 1955. It weighed about . The invention of the ALWAC III-E is attributed to Axel Wenner-Gren, and the name is derived from Axel Leonard Wenner-Gren Automatic Computer, letter E stands for the E-register (index register). The ALWAC III-E contained 132 \- 275 vacuum tubes, 5000 \- 5400 silicon diodes, and cost $60,000 \- $80,000.
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SOAP II Coding form, 1957 The Symbolic Optimal Assembly Program (SOAP) is an assembler for the IBM 650 Magnetic Drum Data-Processing Machine, an early computer first used in 1954. It was developed by Stan Poley at the IBM Thomas J. Watson Research Center. SOAP is called Optimal (or Optimum) because it attempts to store generated instructions on the storage drum to minimize the access time from one instruction to the next. SOAP is a multi-pass assembler, that is, it processes the source program more than once in order to generate the object program.
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Initially the only devices available were germanium point- contact transistors, less reliable than the valves they replaced but which consumed far less power. Their first transistorised computer, and the first in the world, was operational by 1953, and a second version was completed there in April 1955. The 1955 version used 200 transistors, 1,300 solid-state diodes, and had a power consumption of 150 watts. However, the machine did make use of valves to generate its 125 kHz clock waveforms and in the circuitry to read and write on its magnetic drum memory, so it was not the first completely transistorized computer.
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Diagram of a 4×4 plane of magnetic core memory in an X/Y line coincident-current setup. X and Y are drive lines, S is sense, Z is inhibit. Arrows indicate the direction of current for writing. Magnetic drum memories were developed for the US Navy during WW II with the work continuing at Engineering Research Associates (ERA) in 1946 and 1947. ERA, then a part of Univac included a drum memory in its 1103, announced in February 1953. The first mass-produced computer, the IBM 650, also announced in 1953 had about 8.5 kilobytes of drum memory.
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Cobra Mist was based on the Naval Research Laboratory's experimental Magnetic-Drum Radar Equipment ('MADRE'), which was able to reliably detect aircraft at ranges up to from its base in Chesapeake Bay. With prior setup, MADRE was even able to detect rocket launches at Cape Canaveral and atomic tests in Nevada. With this successful demonstration, the US Air Force started plans to deploy a similar system in Turkey; providing coverage of much of the western part of the Soviet Union. Tenders for the system outline were placed in 1964 and bids followed the next year for the actual system itself.
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Kilburn anticipated a return to Malvern but Williams persuaded him to stay to work on the university's collaborative project developing the Ferranti Mark 1, the world's first commercial computer. Max Newman withdrew from the project, believing that the development of computers required engineers and not mathematicians at this point, but Williams preferred to return to electrotechnics, leaving Kilburn in charge. He was assisted by Alan Turing, who arrived at Manchester in 1948. The Mark I incorporated innovations such as index registers, and combined CRTs with magnetic drum storage. Nine Mark I computers were sold by between 1951 and 1957.
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Their first transistorised computer and the first in the world, was operational by 1953, and a second version was completed there in April 1955. However, the machine did make use of valves to generate its 125 kHz clock waveforms and in the circuitry to read and write on its magnetic drum memory, so it was not the first completely transistorized computer. That distinction goes to the Harwell CADET of 1955, built by the electronics division of the Atomic Energy Research Establishment at Harwell. MOSFET (MOS transistor), showing gate (G), body (B), source (S) and drain (D) terminals.
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In this sense, the choice of datum is arbitrary in the sense that no matter which item is sought, all that is needed to find it is its address, i.e. the coordinates at which it is located, such as its row and column (or its track and record number on a magnetic drum). At first, the term "random access" was used because the process had to be capable of finding records no matter in which sequence they were required. However, soon the term "direct access" gained favour because one could directly retrieve a record, no matter what its position might be.
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Magnetic drum memory held the main memory, and the central processing unit (CPU) processor registers, timing information, and the master bit clock, each on a dedicated track. The number of vacuum tubes were kept to a minimum by using solid-state diode logic, a bit-serial architecture and multiple use of each of the 15 flip-flops. It was a binary, 31-bit word computer with a 4096-word drum memory. Standard inputs were the Flexowriter keyboard and paper tape (ten six-bit characters/second). The only printing output was the Flexowriter printer (typewriter, working at 10 characters/second).
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The UNIVAC Solid State was a magnetic drum-based solid-state computer announced by Sperry Rand in December 1958 as a response to the IBM 650. It was one of the first computers to be (nearly) entirely solid-state, using 700 transistors, and 3000 magnetic amplifiers (FERRACTOR) for primary logic, and 20 vacuum tubes largely for power control. It came in two versions, the Solid State 80 (IBM-style 80 column cards) and the Solid State 90 (Remington-Rand 90 column cards). In addition to the "80/90" designation, there were two variants of the Solid State the SS I 80/90 and the SS II 80/90.
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In November 1953 Richard Grimsdale and Douglas Webb of Manchester University first demonstrated their prototype transistorized computer using 92 point-contact transistors and 550 diodes in order to test the suitability of transistors in improving the reliability of the Manchester Mark 1 computer. This machine was similar to the Mark I, except that it did not include Williams tubes and used only the magnetic drum for main memory. The machine was based on a 48-bit word, although 4 bits were used for timing and thus not available for program use. This machine used thermionic valves to generate a clock frequency of 125 kHz.
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Thin magnetic tape was not entirely suited for continuous operation, however, so the tape loop had to be replaced from time to time to maintain the audio fidelity of the processed sounds. The Binson Echorec used a rotating magnetic drum or disc (not entirely unlike those used in modern hard disk drives) as its storage medium. This provided an advantage over tape, as the durable drums were able to last for many years with little deterioration in the audio quality. Often incorporating vacuum tube-based electronics, surviving tape-based delay units are sought by modern musicians who wish to employ some of the timbres achievable with this technology.
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Controls are included in the 704 for: one 711 Punched Card Reader, one 716 Alphabetic Printer, one 721 Punched Card Recorder, five 727 Magnetic Tape Units and one 753 Tape Control Unit, one 733 Magnetic Drum Reader and Recorder, and one 737 Magnetic Core Storage Unit. Weight: about . The 704 itself came with a control console which has 36 assorted control switches or buttons and 36 data input switches, one for each bit in a register. The control console essentially allows only setting the binary values of the registers with switches and seeing the binary state of the registers displayed in the pattern of many small neon tubes, appearing much like modern LEDs.
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CALDIC (the California Digital Computer) was an electronic digital computer built with the assistance of the Office of Naval Research at the University of California, Berkeley between 1951 and 1955 to assist and enhance research being conducted at the university with a platform for high-speed computing. CALDIC was designed to be constructed at a low cost and simple to operate. It was a serial decimal machine with an , 10,000-word magnetic drum memory. (As CALDIC's decimal words were 10 digits each, the magnetic memory could store about 400,000 bits.) It contained 1,300 vacuum tubes, 1,000 crystal diodes, 100 magnetic elements (for the recording heads), and 12 relays (in the power supply).
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In 1928 Vaughan began work in Bell Laboratories, then attended Cooper Union College in New York City, where in 1933 he received a Bachelor of Science degree. Throughout the next decade he worked on a variety of transmission and signaling projects, and in 1944 received the Naval Ordnance Award for his computer work. In 1945 he began research on two experimental switching systems: first the Electronically Controlled Automatic Switching System (ECASS), an experimental system using cold cathode gas tubes, reed switches and a special telephone set, and subsequently the Drum Information Assembler and Dispatcher (DIAD), a magnetic drum system that used vacuum tubes and semiconductor diodes. DIAD was the first switch with memory.
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With various technical, financial and personnel setbacks, the ERMETH was built up as a one-off unit from 1955 onwards and gradually put into operation from 1956 onwards; it performed its task until October 1963, when it was dismantled and packed. A planned licensed version of ERMETH by a private company did not come about. After spatial alterations a CDC 1604A of Control Data Corporation took its place from April 1964. The available computing power at ETH increased by a factor of 100 with the transition from the electromechanical Z4 to the ERMETH, but by a factor of 400 with the transition from the ERMETH with its time-critical magnetic drum memory to the fully electronic CDC 1604A.
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With the basic system up and running, attention turned to a "full sized" version. This machine would use a 44-bit word with 1,024 words of memory backed up with a 10,000 word magnetic drum to be supplied by Ferranti Canada. A new math unit would operate on an entire word in parallel, instead of bit-serial as with most machines of the era, dramatically improving performance so that an addition would take only 20 microseconds and a multiply about 200—faster than the prototype at addition even on its much smaller word size. Success of the UTEC created intense demand within the Canadian research establishment to start construction of the full scale follow-on.
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The machine did however make use of valves to generate its 125 kHz clock waveforms and in the circuitry to read and write on its magnetic drum memory, so it was not the first completely transistorised computer, a distinction that went to the Harwell CADET of 1955. Problems with the reliability of early batches of transistors meant that the machine's mean time between failures was about 90 minutes, which improved once the more reliable junction transistors became available. The Transistor Computer's design was adopted by the local engineering firm of Metropolitan-Vickers in their Metrovick 950, in which all the circuitry was modified to make use of junction transistors. Six Metrovick 950s were built, the first completed in 1956.
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He was told nothing about the work the team would do, but after being visited by a series of increasingly high-ranking naval officers culminating with James Forrestal, he knew "something" was up and decided to give it a try. Norris, Engstrom, and their group incorporated ERA in January, 1946, hired forty of their codebreaking colleagues, and moved to the NAC factory. During the early years, the company took on any engineering work that came their way, but were generally kept in business developing new code-breaking machines for the Navy. Most of the machines were custom-built to crack a specific code, and increasingly used magnetic drum memory in order to process and analyze the coded texts.
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The first was the equipment to store and process the information relating to the setting up and the progress of the calls (the stores used in this part of the equipment were 900 microsecond magnetostriction delay lines). The second was the permanent memory containing the translators and so on, which used the magnetic drum store. In addition, various services, such as the waveform generator and the "clock pulse" generator used to time the system, were provided. During the progress of a call the setting-up apparatus first connected the caller to a register equipment and later connected the caller to their correspondent by way of the "highway" switch, a channel selector choosing a free channel suitable for the call, that was, one available to both subscribers.
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By that time competition from IBM had made the Philco computer operations no longer profitable for Ford, and the division was closed down. Philco 212 at the thumb The Model 212 could carry out a floating-point multiplication in 22 microseconds. Each word contained two 24-bit instructions with 16 bits of address information and eight bits for the opcode. There were 225 different valid opcodes in the Model 212; invalid opcodes were detected and halted the machine. The CPU had an accumulator register of 48 bits, three general-purpose registers of 24 bits, and 32 index registers of 15 bits. Main memory size ranged from 4K words to 64K words. Only the first model had a magnetic drum memory; later editions used tape drives.
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Delay Line 11 (DL11) served as the buffer between the magnetic drum and the high-speed store. Being a "transfer machine", data could be transferred a word at a time, a pair of words at a time, and any number of words up to 33 at a time. Thus, for example, 32 words read from the drum could be transferred as a block to any of the other delay lines; four words could be transferred as a block from one quadruple register to the other, or between a quadruple register and a delay line—all with one instruction. The 32 words of a delay line could be summed by passing them to the single-length adder (by means of a single instruction).
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Section of punched tape showing how one 40-bit word was encoded as eight 5-bit characters. Of the 20 bits allocated for each program instruction, 10 were used to hold the instruction code, which allowed for 1,024 (210) different instructions. The machine had 26 initially, increasing to 30 when the function codes to programmatically control the data transfer between the magnetic drum and the cathode ray tube (CRT) main store were added. On the Intermediary Version programs were input by key switches, and the output was displayed as a series of dots and dashes on a cathode ray tube known as the output device, just as on the Baby from which the Mark 1 had been developed. However, the Final Specification machine, completed in October 1949, benefitted from the addition of a teleprinter with a five-hole paper-tape reader and punch.
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The general-purpose registers had an access time of one microsecond. LARC weighed about . The basic configuration had one Computer and LARC could be expanded to a multiprocessor with a second Computer. The Processor is an independent CPU (with a different instruction set from the Computers) and provides control for 12 to 24 magnetic drum storage units, four to forty UNISERVO II tape drives, two electronic page recorders (a 35mm film camera facing a cathode-ray tube), one or two high-speed printers, and a high- speed punched card reader. The LARC used core memory banks of 2500 words each, housed four banks per memory cabinet. The basic configuration had eight banks of core (two cabinets), 20,000 words. The memory could be expanded to a maximum of 39 banks of core (ten cabinets with one empty bank), 97,500 words.
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In those days it was common for it to be unclear whether a failure was due to the hardware or the program. As a consequence, Christopher Strachey of NRDC who was himself a brilliant programmer, recommended the following design objectives: # The necessity for optimum programming (favoured by Alan Turing) was to be minimised, "because it tended to become a time-wasting intellectual hobby of the programmers"; # The needs of the programmer were to be a governing factor in selecting the instruction set; and # It was to be cheap and reliable. The first objective was only partially met: because both program and the data on which it was to operate had to be in the 128 words of primary storage contained in 8-word nickel delay lines. The rest of the memory was held on a 7936-word magnetic drum which rotated at 3750 rpm, so it was often necessary to use ingenuity to reduce the number of transfers between the fast store and the drum.
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The DEUCE also had an 8192-word magnetic drum for main storage. To access any of the 256 tracks of 32 words, the drum had one group of 16 read and one group of 16 write heads, each group on independent moveable arms, each capable of moving to one of 16 positions. Access time was 15 milliseconds if the heads were already in position; an additional 35 milliseconds was required if the heads had to be moved. There was no rotational delay incurred when reading from and writing to drum. Data was transferred between the drum and one of the 32-word delay lines. The DEUCE could be fitted with paper tape equipment; the reader speed was 850 characters per second, while the paper tape output speed was 25 characters per second. (The DEUCE at the University of New South Wales {UTECOM} had a Siemens teleprinter attached in 1964, giving 10 characters per second input/output). Decca magnetic tape units could also be attached.
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The IBM 7320 is a discontinued magnetic drum, count key data storage unit manufactured by IBM. It was announced on December 10, 1962 for the IBM 7090 and 7094 computer systems, was retained for the earliest System/360 systems, and was discontinued in 1965. The 7320 is a vertically-mounted head-per-track device with 449 tracks, 400 data tracks, 40 alternate tracks, and 9 clock/format tracks. The rotational speed is 3490 rpm, so the average rotational delay is 8.6 milliseconds. Attachment to a 709x system is through an IBM 7631 File Control unit, which can attach up to five random-access storage units, a mix of 7320 and 1301 DASD. One or two 7631 controllers can attach to a computer system, but the system can still attach only a total of five DASD. When used with a 709x, a track holds 2796 six-bit characters, and a 7320 unit holds 1,118,400 characters. Data transfer rate is 202,800 characters per second. The 7320 attaches to a System/360 through a 2841 Storage Control unit.
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Mathematical operations often take place in a stepwise fashion, using the results from one operation as the input to the next. For instance, a manual calculation of a worker's weekly payroll might look something like: # look up the number of hours worked from the employee's time card # look up the pay rate for that employee from a table # multiply the hours by the pay rate to get their basic weekly pay # multiply their basic pay by a fixed percentage to account for income tax # subtract that number from their basic pay to get their weekly pay after tax # multiply that result by another fixed percentage to account for retirement plans # subtract that number from their basic pay to get their weekly pay after all deductions A computer program carrying out the same task would follow the same basic sequence of operations, although the values being looked up would all be stored in computer memory. In early computers, the number of hours would likely be held on a punch card and the pay rate in some other form of memory, perhaps a magnetic drum. Once the multiplication is complete, the result needs to be placed somewhere.
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