This is one of the original 7 prototype Acorn A4 Laptop computers. Kindly donated by Mike Hill.

The machine was later launched in June 1992 and it was their only portable computer. Reportedly based on the A5000 (or may be vice versa) the A4 has the footprint of a sheet of A4 paper (hence the name) and weighs about 3 kg. The A4 came with a carry case with space for the external power supply, manuals and a mouse. The A4 has an ARM3 CPU clocked at 24MHz, 4MB RAM and a 640x480 16 greyscale screen.

The operating system (RISC OS 3.10) was located in the 2 MB ROM. The 9'' LCD screen could only display 14 shades of grey, but used a clever dithering system to make more shades apparent. 

K/Board 84 keys with arrow keys
CPU ARM 3 (with 4 KB of internal RAM cache)
24 mHz (internal CPU) and 12 mHz (bus)
RAM   4MB
ROM   2 MB
Text: Max : 132 x 30
Graphics: 47 graphic modes, maximum 640 x 480 with LCD screen and up to 1152 x 896 with VGA screen
Screen 14 shades of grey (LCD screen)
Sound: 8 voices (stereo 8 bit)
I/O Ports: VGA, Centronics, RS232 C, stereo sound, Mouse, Keyboard
Drive: 3.5'' disk-drive
OS: RISC OS
Cost: £1395 (2Mb floppy version) up to £1895 (4Mb HD120 version)

Manufacturer: Acorn Computers
Date: 1992

This exhibit has a reference ID of CH43777. Please quote this reference ID in any communication with the Centre for Computing History.

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