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Acorn System 1
The Acorn System 1, initially called the Acorn Microcomputer (Micro-Computer), was an early 8-bit microcomputer for hobbyists, based on the MOS 6502 CPU, and produced by British company Acorn Computers from 1979. The main parts of the system were designed by then-Cambridge-undergraduate student Sophie Wilson, with a cassette interface designed by Steve Furber.http://www.stairwaytohell.com/articles/SG-SophieWilson.html Sophie Wilson - 2007 Interview with Stuart Goodwin It was Acorn's first product, and was based on an automated cow feeder. It was a small machine built on two Eurocard-standard circuit boards and it could be purchased ready-built or in kit form. *one card (shown right) with the I/O part of the computer: a LED seven segment display, a 25-key keypad ( hex+function keys), and a cassette CUTS interface (the circuitry to the left of the keypad) *the second card (the computer board - see below), which included the CPU, RAM/ROM memory, and support chips *the two boar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acorn Computers
Acorn Computers Ltd. was a British computer company established in Cambridge, England, in 1978. The company produced a number of computers which were especially popular in the United Kingdom, UK, including the Acorn Electron and the Acorn Archimedes. Acorn's computer dominated the UK educational computer market during the 1980s. Though the company was acquired and largely dismantled in early 1999, with various activities being dispersed amongst new and established companies, its legacy includes the development of reduced instruction set computing (RISC) personal computers. One of its operating systems, , continues to be developed by RISC OS Open. Some activities established by Acorn lived on: technology developed by Arm (company), Arm, created by Acorn as a joint venture with Apple, Inc., Apple and VLSI Technology, VLSI in 1990, is dominant in the mobile phone and personal digital assistant (PDA) microprocessor market. Acorn is sometimes referred to as the "British Apple" and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexadecimal
In mathematics and computing, the hexadecimal (also base-16 or simply hex) numeral system is a positional numeral system that represents numbers using a radix (base) of 16. Unlike the decimal system representing numbers using 10 symbols, hexadecimal uses 16 distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9, and "A"–"F" (or alternatively "a"–"f") to represent values from 10 to 15. Software developers and system designers widely use hexadecimal numbers because they provide a human-friendly representation of binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte can have values ranging from 00000000 to 11111111 in binary form, which can be conveniently represented as 00 to FF in hexadecimal. In mathematics, a subscript is typically used to specify the base. For example, the decimal value would be expressed in hexadecimal as . In programming, a number of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mike Cowlishaw
Mike Cowlishaw is a visiting professor at the Department of Computer Science at the University of Warwick, and a Fellow of the Royal Academy of Engineering. He is a retired IBM Fellow, and was a Fellow of the Institute of Engineering and Technology, and the British Computer Society. He was educated at Monkton Combe School and the University of Birmingham. Career at IBM Cowlishaw joined IBM in 1974 as an electronic engineer but is best known as a programmer and writer. He is known for designing and implementing the Rexx programming language (1984), his work on colour perception and image processing that led to the formation of JPEG (1985), the STET folding editor (1977), the LEXX live parsing editor with colour highlighting for the Oxford English Dictionary (1985), electronic publishing, SGML applications, the IBM Jargon File ''IBMJARG'' (1990), a programmable OS/2 world globe ''PMGlobe'' (1993), ''MemoWiki'' based on his ''GoServe'' Gopher/http server, and the Java-related N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acorn System 5
The Acorn Eurocard systems were a series of modular microcomputer systems based on rack-mounted Eurocards developed by Acorn Computers from 1979 to 1982, aimed primarily at industrial and laboratory use, but also home enthusiasts. The experience gained in developing this modular system strongly influenced the design of Acorn's first all-in-one home computer, the Acorn Atom, released in March 1980; and also much of the circuitry in its successor, the BBC Micro, first shown in late 1981. Acorn's final rack-based machine was the System 5, released in late 1982. The Eurocard business was then sold on to one of its principal resellers, Control Universal Ltd, which continued to develop various cards for industrial use based on the Acorn-standard bus during the 1980s, but ultimately went into receivership in 1989. Eurocards Placing the two Eurocards from the original Acorn Microcomputer onto a backplane made the system straightforward to expand in a modular way. The original I/O card, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acorn System 4
The Acorn Eurocard systems were a series of modular microcomputer systems based on rack-mounted Eurocards developed by Acorn Computers from 1979 to 1982, aimed primarily at industrial and laboratory use, but also home enthusiasts. The experience gained in developing this modular system strongly influenced the design of Acorn's first all-in-one home computer, the Acorn Atom, released in March 1980; and also much of the circuitry in its successor, the BBC Micro, first shown in late 1981. Acorn's final rack-based machine was the System 5, released in late 1982. The Eurocard business was then sold on to one of its principal resellers, Control Universal Ltd, which continued to develop various cards for industrial use based on the Acorn-standard bus during the 1980s, but ultimately went into receivership in 1989. Eurocards Placing the two Eurocards from the original Acorn Microcomputer onto a backplane made the system straightforward to expand in a modular way. The original I/O card, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acorn System 3
The Acorn Eurocard systems were a series of modular microcomputer systems based on rack-mounted Eurocards developed by Acorn Computers from 1979 to 1982, aimed primarily at industrial and laboratory use, but also home enthusiasts. The experience gained in developing this modular system strongly influenced the design of Acorn's first all-in-one home computer, the Acorn Atom, released in March 1980; and also much of the circuitry in its successor, the BBC Micro, first shown in late 1981. Acorn's final rack-based machine was the System 5, released in late 1982. The Eurocard business was then sold on to one of its principal resellers, Control Universal Ltd, which continued to develop various cards for industrial use based on the Acorn-standard bus during the 1980s, but ultimately went into receivership in 1989. Eurocards Placing the two Eurocards from the original Acorn Microcomputer onto a backplane made the system straightforward to expand in a modular way. The original I/O card ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blake's 7
''Blake's 7'' (sometimes styled ''Blakes7'') is a British science fiction television programme produced by the BBC. Four 13-episode series were broadcast on BBC1 between 1978 and 1981. It was created by Terry Nation, who also wrote the first series, produced by David Maloney (series 1–3) and Vere Lorrimer (series 4), and the script editor throughout its run was Chris Boucher, who wrote nine of its episodes. The main character for the first two series was Roj Blake, played by Gareth Thomas. ''Blake's 7'', which was broadcast in 25 other countries, had a low budget but featured many tropes of space opera, such as spaceships, robots, galactic empires and aliens. Critical responses have been varied; some reviewers praised the programme for its dystopian themes, strong characterisation, ambiguous morality and pessimistic tone, as well as displaying an "enormous sense of fun", but others have criticised its production values, dialogue, and accused it of lacking originality. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor–transistor Logic
Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors. Its name signifies that transistors perform both the logic function (the first "transistor") and the amplifying function (the second "transistor"), as opposed to earlier resistor–transistor logic (RTL) and diode–transistor logic (DTL). TTL integrated circuits (ICs) were widely used in applications such as computers, industrial controls, test equipment and instrumentation, consumer electronics, and synthesizers. After their introduction in integrated circuit form in 1963 by Sylvania Electric Products, TTL integrated circuits were manufactured by several semiconductor companies. The 7400 series by Texas Instruments became particularly popular. TTL manufacturers offered a wide range of logic gates, flip-flops, counters, and other circuits. Variations of the original TTL circuit design offered higher speed or lower power dissipation to allow design optimization. TTL devices were original ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Oscillator
A crystal oscillator is an electronic oscillator circuit that uses a piezoelectric crystal as a frequency-selective element. The oscillator frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is a quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators. However, other piezoelectricity materials including polycrystalline ceramics are used in similar circuits. A crystal oscillator relies on the slight change in shape of a quartz crystal under an electric field, a property known as inverse piezoelectricity. A voltage applied to the electrodes on the crystal causes it to change shape; when the voltage is removed, the crystal generates a small voltage as it elastically returns to its original shape. The quartz oscillates at a stable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Read-only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications (like video games) for programmable devices can be distributed as plug-in cartridges containing ROM. Strictly speaking, ''read-only memory'' refers to memory that is hard-wired, such as diode matrix or a mask ROM integrated circuit (IC), which cannot be electronically changed after manufacture. Although discrete circuits can be altered in principle, through the addition of bodge wires and/or the removal or replacement of components, ICs cannot. Correction of errors, or updates to the software, require new devices to be manufactured and to replace the installed device. Floating-gate ROM semiconductor memory in the form of erasab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random-access Memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to be read (computer), read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks, CD-RWs, DVD-RWs and the older Magnetic tape data storage, magnetic tapes and drum memory), where the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement. RAM contains multiplexer, multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, and RAM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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