The Acorn System 1, initially called the Acorn Microcomputer (Micro-Computer), was an early 8-bit

8-bit

The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...

 microcomputer

Microcomputer

A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...

 for hobbyists, based on the MOS 6502

MOS Technology 6502

The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...

 CPU

Central processing unit

The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

, and produced by British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 company Acorn Computers

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 UK. These included the Acorn Electron, the BBC Micro, and the Acorn Archimedes...

 from 1979.
The system was designed by then-Cambridge

University of Cambridge

The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...

-undergraduate student Sophie Wilson

Sophie Wilson

Sophie Wilson is a British computer scientist. She is known for designing the Acorn Micro-Computer, the first of a long line of computers sold by Acorn Computers Ltd, as well as the instruction set of the highly successful ARM processor.- Life and career :...

. 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:

• one card (shown right) with the I/O
  Input/output
  In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...
  
   part of the computer: a LED
  Light-emitting diode
  A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
  
   seven segment display, a 25-key keypad (hex
  Hexadecimal
  In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
  
  +function key
  Function key
  A function key is a key on a computer or terminal keyboard which can be programmed so as to cause an operating system command interpreter or application program to perform certain actions...
  
  s), and a cassette interface (the circuitry to the left of the keypad)
• the second card (the computer board), which included the CPU, RAM
  Random-access memory
  Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
  
  /ROM
  Read-only memory
  Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
  
   memory, and support chips.

Almost all CPU signals were accessible via the standard Eurocard connector.

See also

• Acorn System 2
  Acorn System 2
  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....
  
  , System 3, System 4, System 5
• Acorn Atom
  Acorn Atom
  The Acorn Atom was a home computer made by Acorn Computers Ltd from 1980 to 1982 when it was replaced by the BBC Micro and later the Acorn Electron....
  
  

External links

• Comprehensive information on the System 1, including an emulator – Provided by Mike Cowlishaw
  Mike Cowlishaw
  Mike Cowlishaw is a retired IBM Fellow, a Visiting Professor at the Department of Computer Science at the University of Warwick, and is a Fellow of the Royal Academy of Engineering , the Institute of Engineering and Technology , and the British Computer Society.- Career at IBM :Cowlishaw joined IBM...