An Acorn System 1 board with 5-pin DIN socket added to the left expansion port.

The System 1 was the first commercially available computer produced by CPU Ltd under the trading name of Acorn Computers Ltd. It was designed by Sophie Wilson and marketed as the Acorn Microcomputer in 1979. It was available in kit form for £70 or £81 assembled.

The System 1 consists of 2 Eurocards each measuring 100 x 160mm. The lower board contains the 6502 CPU, 1K RAM, a 16-way RAM I/O chip used by the keyboard, the monitor RAMS and address decoding circuitry. Sockets for an additional RAM I/O and 2K of EPROM are also included. Three switches may be added to the board to generate RESET, Non Masked Interrupt (NMI), and Interrupt Requests (IRQ) signals, or additional devices may be daisy-chained on to the board when more than one device which generates interrupts, or re-sets, is to be connected.

The re-set switch is duplicated on the upper board since the switches are hidden when the boards are mounted together. The upper board also contains the 25-key Hex keyboard, an eight-digit display, and a CUTS cassette interface.

The Acorn Microcomputer would later be developed into the System 2, 3, 4 and 5.

We also have the Acorn System 1 Users Manual in our collection.

This machine was Chris Turner's own.

Manufacturer: Acorn Computers Ltd
Date: March 1979

This exhibit has a reference ID of CH66005. Please quote this reference ID in any communication with the Centre for Computing History.

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