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UNIVAC III
The UNIVAC III, designed as an improved transistorized replacement for the vacuum tube UNIVAC I and UNIVAC II computers, was introduced in June 1962, with Westinghouse agreeing to furnish system programing and marketing on June 1, 1962. It was designed to be compatible for all data formats. However the word size and instruction set were completely different; this presented significant difficulty as all programs had to be rewritten, so many customers switched to different vendors instead of upgrading existing UNIVACs. The UNIVAC III weighed about . The system was engineered to use as little core memory as possible, as it was a very expensive item. The memory system was 25 bits wide and could be configured with from 8,192 words to 32,768 words of memory. Memory was built in stacks of 29 planes of 4,096 cores: 25 for the data word, two for "modulo-3 check" bits, and two for spares. Each memory cabinet held up to four stacks (16,384 words). It supported the following data formats: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor Computer
A transistor computer, now often called a second-generation computer, is a computer which uses discrete transistors instead of vacuum tubes. The first generation of electronic computers used vacuum tubes, which generated large amounts of heat, were bulky and unreliable. A second-generation computer, through the late 1950s and 1960s featured circuit boards filled with individual transistors and magnetic core memory. These machines remained the mainstream design into the late 1960s, when integrated circuits started appearing and led to the third-generation computer. History The University of Manchester's experimental Transistor Computer was first operational in November 1953 and it is widely believed to be the first transistor computer to come into operation anywhere in the world. There were two versions of the Transistor Computer, the prototype, operational in 1953, and the full-size version, commissioned in April 1955. The 1953 machine had 92 point-contact transistors and 5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Tube
A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a thermionic tube or thermionic valve utilizes thermionic emission of electrons from a hot cathode for fundamental electronic functions such as signal amplification and current rectification. Non-thermionic types such as a vacuum phototube, however, achieve electron emission through the photoelectric effect, and are used for such purposes as the detection of light intensities. In both types, the electrons are accelerated from the cathode to the anode by the electric field in the tube. The simplest vacuum tube, the diode (i.e. Fleming valve), invented in 1904 by John Ambrose Fleming, contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through the device—from the cathode to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIVAC I
The UNIVAC I (Universal Automatic Computer I) was the first general-purpose electronic digital computer design for business application produced in the United States. It was designed principally by J. Presper Eckert and John Mauchly, the inventors of the ENIAC. Design work was started by their company, Eckert–Mauchly Computer Corporation (EMCC), and was completed after the company had been acquired by Remington Rand (which later became part of Sperry, now Unisys). In the years before successor models of the UNIVAC I appeared, the machine was simply known as "the UNIVAC".Johnson, L.R., "Coming to grips with Univac," IEEE Annals of the History of Computing , vol. 28, no. 2, pp. 32, 42, April–June 2006. The first Univac was accepted by the United States Census Bureau on March 31, 1951, and was dedicated on June 14 that year. The fifth machine (built for the U.S. Atomic Energy Commission) was used by CBS to predict the result of the 1952 presidential election. With a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIVAC II
The UNIVAC II computer was an improvement to the UNIVAC I that the UNIVAC division of Sperry Rand first delivered in 1958. The improvements included the expansion of core memory from 2,000 to 10,000 words; UNISERVO II tape drives, which could use either the old UNIVAC I metal tapes or the new PET tapes; and some transistorized circuits (although it was still overwhelmingly a vacuum tube computer). It was fully compatible with existing UNIVAC I programs for both code and data. It weighed about . Circuit elements of entire system Above figures are approximate and do not include input-output devices. Programming and numerical system Decimal point occurs at the right of the sign digit. Arithmetic unit Addition, subtraction, and multiplication times given below include reading and executing the instruction. The time includes formation of the result in the accumulator. All instructions, however are performed at minimum latency rates. Magne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Westinghouse Electric Corporation
The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in 1945. The company acquired the CBS television network in 1995 and was renamed "CBS Corporation" until being acquired by Viacom in 1999, a merger completed in April 2000. The CBS Corporation name was later reused for one of the two companies resulting from the split of Viacom in 2006. The Westinghouse trademarks are owned by Westinghouse Electric Corporation, and were previously part of Westinghouse Licensing Corporation. The nuclear power business, Westinghouse Electric Company, was spun off from the Westinghouse Electric Corporation in 1999. History Westinghouse Electric was founded by George Westinghouse in Pittsburgh, Pennsylvania, on January 8, 1886. The firm became active in developing electric infrastructure throughout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core Memory
Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central part of a fruit * Hydrophobic core, the interior zone of a protein * Nuclear reactor core, a portion containing the fuel components * Pit (nuclear weapon) or core, the fissile material in a nuclear weapon * Semiconductor intellectual property core (IP core), is a unit of design in ASIC/FPGA electronics and IC manufacturing * Atomic core, an atom with no valence electrons Geology and astrophysics * Core sample, in Earth science, a sample obtained by coring ** Ice core * Core, the central part of a galaxy; see Mass deficit * Core (anticline), the central part of an anticline or syncline * Planetary core, the center of a planet ** Earth's inner core ** Earth's outer core * Stellar core, the region of a star where nuclear fusion takes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excess-3
Excess-3, 3-excess or 10-excess-3 binary code (often abbreviated as XS-3, 3XS or X3), shifted binary or Stibitz code (after George Stibitz, who built a relay-based adding machine in 1937) is a self-complementary binary-coded decimal (BCD) code and numeral system. It is a biased representation. Excess-3 code was used on some older computers as well as in cash registers and hand-held portable electronic calculators of the 1970s, among other uses. Representation Biased codes are a way to represent values with a balanced number of positive and negative numbers using a pre-specified number ''N'' as a biasing value. Biased codes (and Gray codes) are non-weighted codes. In excess-3 code, numbers are represented as decimal digits, and each digit is represented by four bits as the digit value plus 3 (the "excess" amount): * The smallest binary number represents the smallest value (). * The greatest binary number represents the largest value (). To encode a number such as 127, one s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary-coded Decimal
In computing and electronic systems, binary-coded decimal (BCD) is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits, usually four or eight. Sometimes, special bit patterns are used for a sign or other indications (e.g. error or overflow). In byte-oriented systems (i.e. most modern computers), the term ''unpacked'' BCD usually implies a full byte for each digit (often including a sign), whereas ''packed'' BCD typically encodes two digits within a single byte by taking advantage of the fact that four bits are enough to represent the range 0 to 9. The precise 4-bit encoding, however, may vary for technical reasons (e.g. Excess-3). The ten states representing a BCD digit are sometimes called '' tetrades'' (for the nibble typically needed to hold them is also known as a tetrade) while the unused, don't care-states are named , ''pseudo-decimals'' or ''pseudo-decimal digits''. BCD's main virtue, in comparison to binary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ones Complement
The ones' complement of a binary number is the value obtained by inverting all the bits in the binary representation of the number (swapping 0s and 1s). The name "ones' complement" (''note this is possessive of the plural "ones", not of a singular "one"'') refers to the fact that such an inverted value, if added to the original, would always produce an 'all ones' number (the term "complement" refers to such pairs of mutually additive inverse numbers, here in respect to a non-0 base number). This mathematical operation is primarily of interest in computer science, where it has varying effects depending on how a specific computer represents numbers. A ones' complement system or ones' complement arithmetic is a system in which negative numbers are represented by the inverse of the binary representations of their corresponding positive numbers. In such a system, a number is negated (converted from positive to negative or vice versa) by computing its ones' complement. An N-bit ones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic-tape Data Storage
Magnetic-tape data storage is a system for storing digital information on magnetic tape using digital recording. Tape was an important medium for primary data storage in early computers, typically using large open reels of 7-track, later 9-track tape. Modern magnetic tape is most commonly packaged in cartridges and cassettes, such as the widely supported Linear Tape-Open (LTO) and IBM 3592 series. The device that performs the writing or reading of data is called a tape drive. Autoloaders and tape libraries are often used to automate cartridge handling and exchange. Compatibility was important to enable transferring data. Tape data storage is now used more for system backup, data archive and data exchange. The low cost of tape has kept it viable for long-term storage and archive. Open reels Initially, magnetic tape for data storage was wound on reels. This standard for large computer systems persisted through the late 1980s, with steadily increasing capacity due to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random-access
Random access (more precisely and more generally called direct access) is the ability to access an arbitrary element of a sequence in equal time or any datum from a population of addressable elements roughly as easily and efficiently as any other, no matter how many elements may be in the set. In computer science it is typically contrasted to sequential access which requires data to be retrieved in the order it was stored. For example, data might be stored notionally in a single sequence like a row, in two dimensions like rows and columns on a surface, or in multiple dimensions. However, given all the coordinates, a program can access each record about as quickly and easily as any other. 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FASTRAND
FASTRAND was a magnetic drum mass storage system built by Sperry Rand Corporation (later Sperry Univac) for their UNIVAC 1100 series and 418/490/494 series computers. A FASTRAND subsystem consisted of one or two Control Units and up to eight FASTRAND units. A dual-access FASTRAND subsystem included two complete control units, and provided parallel data paths that allowed simultaneous operations on any two FASTRAND units in the subsystem. Each control unit interfaced to one (optionally two) 1100 Series (36-bit), or 490 Series (30-bit), parallel I/O channels. A voice coil actuator moved a bar containing multiple single track recording heads, so these drums operated much like moving head disk drives with multiple disks. The heads "flew" on self-acting hydrodynamic air bearings. The drums had a plated magnetic recording surface. An optional feature called Fastband included 24 additional tracks with fixed read/write heads. This feature provided rapid access (35 ms. average access time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
