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A minicomputer, or colloquially mini, is a type of smaller general-purpose computer developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, The New York Times suggested a consensus definition of a minicomputer as a machine costing less than US$25,000, with an input-output device such as a teleprinter and at least four thousand words of memory, that is capable of running programs in a higher level language, such as Fortran or BASIC.
Programmed Data Processor (PDP), referred to by some customers, media and authors as "Programmable Data Processor," is a term used by the Digital Equipment Corporation from 1957 to 1990 for several lines of minicomputers.
The PDP–11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the late 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, making it one of DEC's most successful product lines. The PDP-11 is considered by some experts to be the most popular minicomputer.
VAX is a series of computers featuring a 32-bit instruction set architecture (ISA) and virtual memory that was developed and sold by Digital Equipment Corporation (DEC) in the late 20th century. The VAX-11/780, introduced October 25, 1977, was the first of a range of popular and influential computers implementing the VAX ISA. The VAX family was a huge success for DEC, with the last members arriving in the early 1990s. The VAX was succeeded by the DEC Alpha, which included several features from VAX machines to make porting from the VAX easier.
In computer architecture, 8-bit integers or other data units are those that are 8 bits wide. Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. Memory addresses for 8-bit CPUs are generally larger than 8-bit, usually 16-bit. 8-bit microcomputers are microcomputers that use 8-bit microprocessors.
A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PCB). Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors. The predecessors to these computers, mainframes and minicomputers, were comparatively much larger and more expensive. Many microcomputers are also personal computers. An early use of the term "personal computer" in 1962 predates microprocessor-based designs. (See "Personal Computer: Computers at Companies" reference below). A "microcomputer" used as an embedded control system may have no human-readable input and output devices. "Personal computer" may be used generically or may denote an IBM PC compatible machine.
A superminicomputer, colloquially supermini, is a high-end minicomputer. The term is used to distinguish the emerging 32-bit architecture midrange computers introduced in the mid to late 1970s from the classical 16-bit systems that preceded them. The development of these computers was driven by the need of applications to address larger memory. The term midicomputer had been used earlier to refer to these systems. Virtual memory was often an additional criteria that was considered for inclusion in this class of system. The computational speed of these machines was significantly greater than the 16-bit minicomputers and approached the performance of small mainframe computers. The name has at times been described as a "frivolous" term created by "marketeers" that lacks a specific definition. Describing a class of system has historically been seen as problematic: "In the computer kingdom, taxonomic classification of equipment is more of a black art than a science." There is some disagreement about which systems should be included in this class. The origin of the name is uncertain.
The Data General RDOS is a real-time operating system released in 1970. The software was bundled with the company's popular Nova and Eclipse minicomputers.
The history of computing hardware starting at 1960 is marked by the conversion from vacuum tube to solid-state devices such as transistors and then integrated circuit (IC) chips. Around 1953 to 1959, discrete transistors started being considered sufficiently reliable and economical that they made further vacuum tube computers uncompetitive. Metal–oxide–semiconductor (MOS) large-scale integration (LSI) technology subsequently led to the development of semiconductor memory in the mid-to-late 1960s and then the microprocessor in the early 1970s. This led to primary computer memory moving away from magnetic-core memory devices to solid-state static and dynamic semiconductor memory, which greatly reduced the cost, size, and power consumption of computers. These advances led to the miniaturized personal computer (PC) in the 1970s, starting with home computers and desktop computers, followed by laptops and then mobile computers over the next several decades.
An index register in a computer's CPU is a processor register used for pointing to operand addresses during the run of a program. It is useful for stepping through strings and arrays. It can also be used for holding loop iterations and counters. In some architectures it is used for read/writing blocks of memory. Depending on the architecture it may be a dedicated index register or a general-purpose register. Some instruction sets allow more than one index register to be used; in that case additional instruction fields may specify which index registers to use.
The PDP-5 was Digital Equipment Corporation's first 12-bit computer, introduced in 1963.
Am2900 is a family of integrated circuits (ICs) created in 1975 by Advanced Micro Devices (AMD). They were constructed with bipolar devices, in a bit-slice topology, and were designed to be used as modular components each representing a different aspect of a computer control unit (CCU). By using the bit slicing technique, the Am2900 family was able to implement a CCU with data, addresses, and instructions to be any multiple of 4 bits by multiplying the number of ICs. One major problem with this modular technique was that it required a larger number of ICs to implement what could be done on a single CPU IC. The Am2901 chip included an arithmetic logic unit (ALU) and 16 4-bit processor register slices, and was the "core" of the series. It could count using 4 bits and implement binary operations as well as various bit-shifting operations. The Am2909 was a 4-bit-slice address sequencer that could generate 4-bit addresses on a single chip, and by using n of them, it was able to generate 4n-bit addresses. It had a stack that could store a microprogram counter up to 4 nest levels, as well as a stack pointer.
Pascal MicroEngine is a series of microcomputer products manufactured by Western Digital from 1979 through the mid-1980s, designed specifically to run the UCSD p-System efficiently. Compared to other microcomputers, which use a machine language p-code interpreter, the Pascal MicroEngine has its interpreter implemented in microcode; p-code is its machine language. The most common programming language used on the p-System is Pascal.
In computer architecture, 16-bit integers, memory addresses, or other data units are those that are 16 bits wide. Also, 16-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers, address buses, or data buses of that size. 16-bit microcomputers are microcomputers that use 16-bit microprocessors.
The K 1840, full name RVS K 1840 is a minicomputer from the German Democratic Republic (GDR). Its development began in August 1985 at VEB Robotron Elektronik in Dresden, and it went into production in 1988.
Simulation for Automatic Machinery or SAM were two unique minicomputers built by the Norwegian Defence Research Establishment (NDRE) in the mid-1960s. SAM 1, built between 1962 and 1964, was the first Norwegian-built programmable computer. It featured 4,096 14-bit words of memory and 14 registers and was used in-house at NDRE. SAM 2 was built between 1966 and 1967 and was used for analysis of satellite imagery at Tromsø Satellite Station. A third-generation computer, it was among the first three in the world to use integrated circuits.
Digico was a British computer company founded in 1965 by Keith Trickett and Avo Hiiemae, two ex-ICL electronics engineers. Former MP Eric Lubbock became chairman in 1969. The company was based in Letchworth initially, moving to a new factory in Stevenage in 1973 and employing about 90 staff.
A transfluxor was a specialised type of magnetic core memory element in which each core had two holes, one for writing and another for reading. It had the unusual property that a core's state could be read without erasing it. In addition to binary data, transfluxors could also store analog values, with no need to drive them into core saturation.
The Arma Engineering Company was an American military technology manufacturer founded in New York in 1918 by Arthur Davis and David Mahood.
References
- ↑ Sanderson, Peter C. (2014-05-12). Minicomputers. Newnes. p. 4. ISBN 978-1-4831-9223-9.
- ↑ Shirriff, Ken. "The first microcomputer: The transfluxor-powered Arma Micro Computer from 1962" . Retrieved 2024-03-04.
- ↑ US3048828A,Cataldo, Ottavio C.,"Memory device",issued 1962-08-07
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