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18-bit
Eighteen binary digits have 262,144 (1000000 octal, 40000 hexadecimal) distinct combinations. Eighteen bits was a common word size for smaller computers in the 1960s, when large computers often using 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 division of Remington Rand 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-15
The PDP-15 was an 18-bit minicomputer by Digital Equipment Corporation that first shipped in February 1970. It was the fifth and last of DEC's 18-bit machines, a series that had started in December 1959 with the PDP-1. More than 400 were ordered within the first eight months. A later model, the PDP-15/76, was bundled with a complete PDP-11, allowing the PDP-15 to use peripherals for the PDP-11's popular Unibus system. The last PDP-15 was produced in 1979, with total sales of about 790 units. The PDP-15 was essentially a version of the earlier PDP-9 that was constructed using small-scale integration integrated circuits, which made it smaller and less expensive than the PDP-9's flip chips which used individual transistors. A basic 8 kW PDP-9 cost about $35,000 in 1968 (), whereas the PDP-15 with 4 kW was only $15,600 () and a fully-equipped system with 8 kW, punch tape, KSR-35 terminal, math coprocessor and dual DECtape was $36,000 (), making a complete system significantly le ... [...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 (computer architecture), word length and slightly extending the instruction set. The main difference was a greatly 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, Mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-7
The PDP-7 is an 18-bit computing, 18-bit minicomputer produced by Digital Equipment Corporation as part of the Programmed Data Processor, PDP series. Introduced in 1964, shipped since 1965, it was the first to use their Flip-Chip module, 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 wrap, wire-wrapped PDP computer. The computer has a memory cycle time of and an add time of . Input/output (I/O) includes a keyboard, printer, punched tape and dual transport DECtape drives (type 555). The standard Magnetic-core memory, core memory capacity is but expandable up to The PDP-7 weighs 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) ... [...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 are the PDP-1, PDP-4 and PDP-7. Its successor is the PDP-15. Hardware The PDP-9, which is "two metres wide and about 75cm deep," is approximately twice the speed of the PDP-7. It was built using discrete transistors, and has an optional integrated vector graphics terminal. The PDP-9 has a memory cycle time of 1 microsecond, and weighs about . The PDP-9/L has a memory cycle time of 1.5 microseconds, and weighs about . It is DEC's first microprogrammed machine. A typical configuration included: * 300 cps paper tape reader * 50 cps paper tape punch * DECtape for operating system and user files * 10 cps console teleprinter, Model 33 KSR Among the improvements of the PDP-9 over its PDP-7 predecessor are: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIVAC 418
The UNIVAC 418 was a transistorized computer made by Sperry Univac. It had 18-bit words and used magnetic-core memory. The name came from its 4-microsecond memory cycle time and 18-bit word. The assembly language for this class of computers was TRIM III and ART418. Over the three different models, more than 392 systems were manufactured. It evolved from the Control Unit Tester (CUT), a device used in the factory to test peripherals for larger systems. Architecture The instruction word had three formats: :''Format I'' - common Load, Store, and Arithmetic operations *f - Function code (6 bits) *u - Operand address (12 bits) :''Format II'' - Constant arithmetic and Boolean functions *f - Function code (6 bits) *z - Operand address or value (12 bits) :''Format III'' - Input/Output *f - Function code (6 bits) *m - Minor function code (6 bits) *k - Designator (6 bits) used for channel number, shift count, etc. Numbers were represented in ones' complement, single and double precis ... [...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 he was 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 early 1960s. The company produced a series of machines known as the Programmed Data Processor, 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 t ... [...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 character encoding scheme used in IBM's SHARE Operating System for representing object code symbols, DEC's variant ... [...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 known for being the most important computer in the creation of hacker culture at the Massachusetts Institute of Technology, Bolt, Beranek and Newman, and elsewhere. The PDP-1 is the original hardware for one of the first video games, Steve Russell's 1962 game '' Spacewar!.'' Description The PDP-1 uses an 18-bit word size and has 4096 words as standard main memory (equivalent in bit size to 9,216 eight-bit bytes, but in character size to 12,388 bytes since the system actually divides an 18-bit word into three 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 instruc ... [...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 (PDP-7, 7, PDP-9, 9 and PDP-15, 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 is 8 microseconds, compared to 5 microseconds for the PDP-1. The PDP-4 weighs 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 Magnetic tape data storage#Bytes per inch, 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 “per ... [...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 eac ... [...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 Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...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. The company 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 se ... [...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 In computing, an address space defines a range of discrete addresses, each of which may correspond to a network host, peripheral device, disk sector, a memory cell or other logical or p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
