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1980s Computers Explanation of terms

The System 1

System 1 boards


Acorn Computers Ltd (UK)


System 1

Date Launched

April 1979


£75 as a kit
£91 ready built
Power supply £7 extra

Microprocessor type

MOSTEK 6502 @ 1.006 MHz

ROM size

512 bytes

Standard RAM

1156 bytes

Maximum RAM

32 kilobytes with external cards

Keyboard type

25 click keys covering hexadecimal digits and commands

Supplied language

Monitor program for viewing and editing memory contents.
Acorn integer BASIC was an optional extra.

Text resolution

8 digit, 7-segment LED

Graphics resolution

No graphics

Colours available

A VDU interface giving 25 lines of 40 characters in eight colours could be added for £101.

Example Screenshot

System 1 LED display
The standard display of the System 1 was just calculator-style LEDs, here showing the contents of a memory address.



Cassette load speed

300 baud

Dimensions (mm)
Weight (grams)

Two cards each 160 x 100 x 25
Not known

Special features

Designed for expandability - optional extras included EPROMs, serial/parallel interfaces, floppy disk drives, EPROM programmer, full ASCII keyboard.

Good points

Low price for the basic system.

Bad points

Relatively expensive when fully expanded with extra memory, disk drives, keyboard, VDU display etc.

How successful?

Moderately successful in itself but it led on to the Atom and highly popular BBC Model B computers.


System 1 consisted of two Eurocard sized circuit boards. One held the keyboard and display and the other the processor, memory and support chips. They could be stacked one above the other for neatness.
The System 1 was clearly intended as a learning aid in the new field of computing, and was designed to have extra ROMS and input/output lines added so that it could be used as a programmable controller for other hardware. It was not really a standalone desktop machine.
Systems 2 to 5 followed, which were the same general design but came with more RAM, built-in Acorn BASIC, the VDU interface as standard, a full keyboard and a rack-mount case. The series was withdrawn in about 1982.
Review of the System 1
Review of the System 3

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