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18-bit
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] |
PDP-10
Digital Equipment Corporation (DEC)'s PDP-10, later marketed as the DECsystem-10, is a mainframe computer family manufactured beginning in 1966 and discontinued in 1983. 1970s models and beyond were marketed under the DECsystem-10 name, especially as the TOPS-10 operating system became widely used. The PDP-10's architecture is almost identical to that of DEC's earlier PDP-6, sharing the same 36-bit word length and slightly extending the instruction set (but with improved hardware implementation). Some aspects of the instruction set are unusual, most notably the ''byte'' instructions, which operate on bit fields of any size from 1 to 36 bits inclusive, according to the general definition of a byte as ''a contiguous sequence of a fixed number of bits''. The PDP-10 was found in many university computing facilities and research labs during the 1970s, the most notable being Harvard University's Aiken Computation Laboratory, MIT's AI Lab and Project MAC, Stanford's SAIL, Computer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-15
The PDP-15 was the fifth and last of the 18-bit minicomputers produced by Digital Equipment Corporation. The PDP-1 was first delivered in December 1959 and the first PDP-15 was delivered in February 1970. More than 400 of these successors to the PDP-9 (and 9/L) were ordered within the first eight months. In addition to operating systems, the PDP-15 had compilers for Fortran and ALGOL. History The 18-bit PDP systems preceding the PDP-15 were named PDP-1, PDP-4, PDP-7 & PDP-9. The last PDP-15 was produced in 1979. Hardware The PDP-15 was DEC's only 18-bit machine constructed from TTL integrated circuits rather than discrete transistors, and, like every DEC 18-bit system could be equipped with: * an optional X-Y (point-plot or vector graphics) display. * a hardware floating point option, with a 10x speedup, was offered. * up to 128Kwords of core main memory Models The PDP-15 models offered by DEC were: * PDP-15/10: a 4K-word paper-tape based system * PDP-15/20: 8K, added DECta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-9
The PDP-9, the fourth of the five 18-bit minicomputers produced by Digital Equipment Corporation, was introduced in 1966. A total of 445 PDP-9 systems were produced, of which 40 were the compact, low-cost PDP-9/L units.. History The 18-bit PDP systems preceding the PDP-9 were the PDP-1, PDP-4 and PDP-7. Its successor was the PDP-15. Hardware The PDP-9, which was "two metres wide and about 75cm deep," was approximately twice the speed of the PDP-7. It was built using discrete transistors, and had an optional integrated vector graphics terminal. The PDP-9 weighed about and the PDP-9/L weighed about . It was DEC's first microprogrammed machine. A typical configuration included: * 300 cps Paper Tape Reader * 50 cps Paper Tape Punch * 10 cps Console Teleprinter, Model 33 KSR Among the improvements of the PDP-9 over its PDP-7 predecessor were: * the addition of Status flags for reader and punch errors, thus providing added flexibility and for error detection * an entirely new ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until forced to resign in 1992, after the company had gone into precipitous decline. The company produced many different product lines over its history. It is best known for the work in the minicomputer market starting in the mid-1960s. The company produced a series of machines known as the PDP line, with the PDP-8 and PDP-11 being among the most successful minis in history. Their success was only surpassed by another DEC product, the late-1970s VAX "supermini" systems that were designed to replace the PDP-11. Although a number of competitors had successfully competed with Digital through the 1970s, the VAX cemented the company's place as a leading vendor in the computer space. As microcomputers improved in the late 1980s, especially wit ... [...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] |
PDP-7
The PDP-7 was a minicomputer produced by Digital Equipment Corporation as part of the PDP series. Introduced in 1964, shipped since 1965, it was the first to use their Flip-Chip technology. With a cost of , it was cheap but powerful by the standards of the time. The PDP-7 is the third of Digital's 18-bit machines, with essentially the same instruction set architecture as the PDP-4 and the PDP-9. Hardware The PDP-7 was the first wire-wrapped PDP computer. The computer had a memory cycle time of and an add time of . Input/output (I/O) included a keyboard, printer, punched tape and dual transport DECtape drives (type 555). The standard core memory capacity was but expandable up to The PDP-7 weighed about . Software DECsys, the first operating system for DEC's 18-bit computer family (and DEC's first operating system for a computer smaller than its 36-bit timesharing systems), was introduced in 1965. It provided an interactive, single user, program development environment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-1
The PDP-1 (''Programmed Data Processor-1'') is the first computer in Digital Equipment Corporation's PDP series and was first produced in 1959. It is famous for being the computer most important in the creation of hacker culture at Massachusetts Institute of Technology, BBN and elsewhere. The PDP-1 is the original hardware for playing history's first game on a minicomputer, Steve Russell's ''Spacewar!'' Description The PDP-1 uses an 18-bit word size and has 4096 words as standard main memory (equivalent to 9,216 eight-bit bytes, though the system actually divides an 18-bit word into six-bit characters), upgradable to 65,536 words. The magnetic-core memory's cycle time is 5.35 microseconds (corresponding roughly to a clock speed of 187 kilohertz); consequently most arithmetic instructions take 10.7 microseconds (93,458 operations per second) because they use two memory cycles: the first to fetch the instruction, the second to fetch or store the data word. Signed numbers are r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-4
The PDP-4 was the successor to the Digital Equipment Corporation's PDP-1. History This 18-bit machine, first shipped in 1962, was a compromise: "with slower memory and different packaging" than the PDP-1, but priced at $65,000 - less than half the price of its predecessor. All later 18-bit PDP machines ( 7, 9 and 15) are based on a similar, but enlarged instruction set, more powerful than, but based on the same concepts as, the 12-bit PDP-5/PDP-8 series. Approximately 54 were sold. Hardware The system's memory cycle was 8 microseconds, compared to 5 microseconds for the PDP-1. The PDP-4 weighed about . Mass storage Both the PDP-1 and the PDP-4 were introduced as paper tape-based systems. The only use, if any, for IBM-compatible 200 BPI or 556 BPI magnetic tape was for data. The use of "mass storage" drums - not even a megabyte and non-removable - were an available option, but were not in the spirit of the “personal” or serially shared systems that DEC offered. It wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
36-bit
36-bit computers were popular in the early mainframe computer era from the 1950s through the early 1970s. Starting in the 1960s, but especially the 1970s, the introduction of 7-bit ASCII and 8-bit EBCDIC led to the move to machines using 8-bit bytes, with word sizes that were multiples of 8, notably the 32-bit IBM System/360 mainframe and Digital Equipment VAX and Data General MV series superminicomputers. By the mid-1970s the conversion was largely complete, and microprocessors quickly moved from 8-bit to 16-bit to 32-bit over a period of a decade. The number of 36-bit machines rapidly fell during this period, offered largely for backward compatibility purposes running legacy programs. History Prior to the introduction of computers, the state of the art in precision scientific and engineering calculation was the ten-digit, electrically powered, mechanical calculator, such as those manufactured by Friden, Marchant and Monroe. These calculators had a column of keys for ea ... [...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] |
IBM 7700 Data Acquisition System
The IBM 7700 Data Acquisition System was announced by IBM on December 2, 1963. It is capable of collecting data from as many as 32 sources simultaneously, process the data and transmit results to up to 16 remote printers, display units or plot boards. The IBM 7700 was short-lived, being replaced by the IBM 1800 Data Acquisition and Control System on November 30, 1964. Two IBM 7700 Data Acquisition Systems are known to have existed: one at the University of Rochester and the other at Stanford University. Both were donated by IBM. The IBM 7700 is an 18-bit system, with instructions occupying two 18-bit words. Arithmetic instructions generally execute in two or three machine cycles, except for multiply, about 8 cycles, and divide, 12 cycles. A machine cycle is two microseconds. Address space is 262,144 words, but the two machines known to have been built had 16,384, 32,768 or 49,152 words. The IBM 7700 is contemporary with the IBM 7000 series The IBM 700/7000 series is a ... [...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] |
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