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18-bit Computers
18 binary digits have (1000000 octal, 40000 hexadecimal) distinct combinations. 18 bits was a common word size for smaller computers in the 1960s, when large computers often used 36 bit words and 6-bit character sets, sometimes implemented as extensions of BCD, were the norm. There were also 18-bit teletypes experimented with in the 1940s. Example computer architectures Possibly the most well-known 18-bit computer architectures are the PDP-1, PDP-4, PDP-7, PDP-9 and PDP-15 minicomputers produced by Digital Equipment Corporation from 1960 to 1975. Digital's PDP-10 used 36-bit words but had 18-bit addresses. The UNIVAC produced several 18-bit computers, including the UNIVAC 418 and several military systems. The IBM 7700 Data Acquisition System was announced by IBM on December 2, 1963. The BCL Molecular 18 was a group of systems designed and manufactured in the UK in the 1970s and 1980s. The NASA Standard Spacecraft Computer NSSC-1 was developed as a standard component f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octet (computing)
The octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, as the byte has historically been used for storage units of a variety of sizes. The term ''octad(e)'' for eight bits is no longer common. Definition The international standard IEC 60027-2, chapter 3.8.2, states that a byte is an octet of bits. However, the unit byte has historically been platform-dependent and has represented various storage sizes in the history of computing. Due to the influence of several major computer architectures and product lines, the byte became overwhelmingly associated with eight bits. This meaning of ''byte'' is codified in such standards as ISO/IEC 80000-13. While ''byte'' and ''octet'' are often used synonymously, those working with certain legacy systems are careful to avoid ambiguity. Octets can be represented using number systems of varying bases such as the hexadeci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIVAC
UNIVAC (Universal Automatic Computer) was a line of electronic digital stored-program computers starting with the products of the Eckert–Mauchly Computer Corporation. Later the name was applied to a division of the Remington Rand company and successor organizations. The BINAC, built by the Eckert–Mauchly Computer Corporation, was the first general-purpose computer for commercial use, but it was not a success. The last UNIVAC-badged computer was produced in 1986. History and structure J. Presper Eckert and John Mauchly built the ENIAC (Electronic Numerical Integrator and Computer) at the University of Pennsylvania's Moore School of Electrical Engineering between 1943 and 1946. A 1946 patent rights dispute with the university led Eckert and Mauchly to depart the Moore School to form the Electronic Control Company, later renamed Eckert–Mauchly Computer Corporation (EMCC), based in Philadelphia, Pennsylvania. That company first built a computer called BINAC (BINar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DEC SIXBIT
A six-bit character code is a character encoding designed for use on computers with word lengths a multiple of 6. Six bits can only encode 64 distinct characters, so these codes generally include only the upper-case letters, the numerals, some punctuation characters, and sometimes control characters. The 7-track magnetic tape format was developed to store data in such codes, along with an additional parity bit. Types of six-bit codes An early six-bit binary code was used for Braille, the reading system for the blind that was developed in the 1820s. The earliest computers dealt with numeric data only, and made no provision for character data. Six-bit BCD, with several variants, was used by IBM on early computers such as the IBM 702 in 1953 and the IBM 704 in 1954. Six-bit encodings were replaced by the 8-bit EBCDIC code starting in 1964, when System/360 standardized on 8-bit bytes. There are some variants of this type of code (see below). Six-bit character codes generally succee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baudot Code
The Baudot code is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of five bits, sent over a communication channel such as a telegraph wire or a radio signal by asynchronous serial communication. The symbol rate measurement is known as baud, and is derived from the same name. History Baudot code (ITA1) In the below table, Columns I, II, III, IV, and V show the code; the Let. and Fig. columns show the letters and numbers for the Continental and UK versions; and the sort keys present the table in the order: alphabetical, Gray and UK Baudot developed his first multiplexed telegraph in 1872 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DEC Radix-50
RADIX 50 or RAD50 (also referred to as RADIX50, RADIX-50 or RAD-50), is an uppercase-only character encoding created by Digital Equipment Corporation (DEC) for use on their DECsystem, PDP, and VAX computers. RADIX 50's 40-character repertoire (050 in octal) can encode six characters plus four additional bits into one 36-bit machine word (PDP-6, PDP-10/DECsystem-10, DECSYSTEM-20), three characters plus two additional bits into one 18-bit word (PDP-9, PDP-15), or three characters into one 16-bit word (PDP-11, VAX). The actual encoding differs between the 36-bit and 16-bit systems. 36-bit systems In 36-bit DEC systems RADIX 50 was commonly used in symbol tables for assemblers or compilers which supported six-character symbol names from a 40-character alphabet. This left four bits to encode properties of the symbol. For its similarities to the SQUOZE encoding scheme used in IBM's SHARE Operating System for representing object code symbols, DEC's variant was also s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flying-spot Store
The flying-spot store was an optical digital memory used in early stored program control components of electronic switching systems. The flying-spot store used a photographic plate as the store of binary data. Each ''spot'' on the plate was an opaque (logical 0) or transparent (logical 1) area that stored one bit. Spots were read and written with an optical mechanism with an access time of ca. one microsecond. The optical system consisted of a cathode ray tube that functioned as a flying-spot scanner, the source of light beams produced on its face and focused onto the photographic plates with a system of lenses. A photomultiplier detected the light beam. The light beam could be split into several components to read multiple plates simultaneously, permitting the formation of a group of bits for each location. A flying-spot store was the main permanent program and data memory for the first electronic central office installed on a trial basis in Morris, Illinois in 1960. The memor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goddard Space Flight Center
The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory located approximately northeast of Washington, D.C. in Greenbelt, Maryland, United States. Established on May 1, 1959 as NASA's first space flight center, GSFC employs approximately 10,000 civil servants and contractors. It is one of ten major NASA field centers, named in recognition of American rocket propulsion pioneer Robert H. Goddard. GSFC is partially within the former Goddard census-designated place; it has a Greenbelt mailing address.CENSUS 2000 BLOCK MAP: GODDARD CDP " . Retrieved on September 1, 2018. 1990 Census map of Prince ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MultiMission Modular Spacecraft
Multi-mission Modular Spacecraft, also known as the MMS, was originally designed by NASA to serve the largest array of functions for the space program possible to decrease the cost of space missions. It was designed to operate in four distinct areas of missions. The MMS began development about a decade before it became implemented in the 1980s and 1990s. The basic MMS was made up of three different modules. They include the altitude control, communications and data handling, and the power subsystems. The idea of a modular system serving many purposes was the pioneer of the leading systems within the space technology ecosystem today as it has left a lasting legacy. The MMS was intended to be "Shuttle compatible", i.e. recoverable/serviceable by the Space Shuttle orbiter. Missions It was used for: * Solar Maximum Mission (SMM), 1980 * Landsat 4, 1982 * Landsat 5, 1984 * Upper Atmosphere Research Satellite (UARS), 1991 * Extreme Ultraviolet Explorer (EUVE), 1992 * TOPEX/Poseidon, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NSSC-1
The NASA Standard Spacecraft Computer-1 (NSSC-1) is a computer developed as a standard component for the MultiMission Modular Spacecraft at the Goddard Space Flight Center (GSFC) in 1974. The basic spacecraft was built of standardized components and modules, for cost reduction. The computer had 18 bit wide core memory or plated wire memory; up to 64 k. 18 bits was chosen because it gave more accuracy (x4) for data over a 16 bit machine. Floating point arithmetic was not supported. Usage The NSSC-1 was used on the * Solar Maximum Mission * Hubble Space Telescope (for spacecraft control, not image data handling which initially used the DF-224) * Landsat-D,D' Missions, renamed Landsat 4 and Landsat 5 and other missions that were mostly limited to the solar system, eg Gamma Ray Observatory, and UARS. The prior OBP hardware was developed by Westinghouse and GSFC. The machine used diode–transistor logic, the lowest power parts available at the time on the preferred parts list; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BCL Molecular
The BCL Molecular 18 was a range of 18-bit computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...s designed and manufactured in the UK from 1970 until the late 1980s.The machines were originally manufactured by Systemation Limited and sold by Business Mechanisation Limited. The two companies merged in 1968 to form Business Computers Limited - later a public limited company. Business Computers Ltd subsequently went into receivership in 1974. It was purchased from the receiver by Computer World Trade, maintenance of existing machines was by a subsidiary of CWT called CFM, manufacturing was passed to ABS Computer in the old BCL building in Portslade and sales rights were sold to a team from the old Singer Computers by 1976 trading as Business Computers (Systems) Ltd selling the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
