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Jupiter Ace

The Jupiter ACE was a British home computer of the 1980s, marketed by a company named Jupiter Cantab. The company was formed by Richard Altwasser and Stephen Vickers, who had been on the design team for the Sinclair ZX Spectrum.

The Jupiter ACE somewhat resembled a ZX81 in a white case, with black rubber keys like the Spectrum. It displayed output on a television, and programs could be saved and loaded on cassette tape, as was standard at that time. The machine came with 3 KB RAM, expandable to 49 K. It had its own RAM packs, which are very rare and fetch high prices, however a ZX81 Pack can be used with an adaptor.

While it had only one video mode, text only, which displayed 24 rows of 32 columns of characters in black and white, it was possible to display graphics, by redefining the 8×8 pixel bitmap of any of the 128 characters. Like the ZX Spectrum, the machine's audio capabilities were restricted to beeps of programmable frequency and duration, output through a small built-in speaker.

The major difference from the 'introductory computer' that was the ZX81, however, was that the Jupiter ACE's designers, from the outset, intended the machine to be for programmers: the machine came with Forth as its default programming language. Though this gave a great speed advantage over the interpreted BASIC that was used on other machines, it did, along with the meager sound and graphics capabilities compared to the upcoming competition, keep the ACE squarely in a niche market. Sales of the machine were never very large. The reported number of Ace’s sold before Jupiter Cantab closed for business was around 8,000. Surviving machines are quite uncommon, fetching quite high prices as collectors items.
   Jupiter Aces General Specifications.
  • CPU: Z80A running at 3.25 MHz
  • Language: O/S: Ace Forth [not a standard fig-Forth or Forth-79].
  • ROM: 2 x 4kB Eproms containing the FORTH compiler and editor.
  • RAM: 3 kB expandable to 51kB.
  • Program Storage: 1500 baud cassette tape.
  • Video Display: 32 x 24 Monochrome Graphics, High Res: 64 x 48,
    all 128 characters redefinable.
  • Keyboard: 40 key rubber membrane, with auto-repeat on every key,
    and two shift keys allow ASCII codes to be produced.
  • Sound: Single channel buzzer.
  • Interfaces: TV connector [UHF TV set to Channel 36], Cassette port x2: Ear & Mic,
    power (9v), two edge connectors: first has a complete address and data lines from
    the cpu, Second: has data and some selection lines.
  • Size: 215 x 190 x 30 mm.
  • Wait: 246g.
  • Documentation: 182 page Users manual.
  • Price at launch £89.95
The above information was taken from  Further information can also be found at

Manufacturer: Jupiter Cantab
Date: 1st January 1982

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Jupiter Ace Manuals:

Item Manufacturer Date
Jupiter Ace Forth Programming The Leagrave Press Unknown
Jupiter Ace - Spreadsheet - User's Manual Boldfield Limited Computing Unknown
Jupiter Ace - Database - User's Manual Boldfield Limited Computing Unknown

Magazines RELATED to Jupiter Ace in our Library

Item Manufacturer Date
Your Computer - October 1982 Oct 1982
Practical Computing - January 1983 Jan 1983

Catalogues RELATED to Jupiter Ace in our Library

Item Manufacturer Date
Jupiter Ace - London Computer Fair Advert Boldfield Limited Computing Unknown
Jupiter Ace - Software Order Form and Holiday Competition Boldfield Limited Computing Unknown
Jupiter Ace - Software Order Form (Software Bonanza!) Boldfield Limited Computing Unknown
Jupiter Ace - Software and Accessories Catalogue Boldfield Limited Computing 1984

Other Systems Related To Jupiter Ace:

Item Manufacturer Date
Jupiter Ace Jupiter Cantab 1st January 1982
Jupiter Ace Jupiter Cantab 1st January 1982
Jupiter Ace in replacement Camputers Lynx Case Jupiter Cantab 1983

This exhibit has a reference ID of CH44385. Please quote this reference ID in any communication with the Centre for Computing History.


Jupiter Ace

  Games Archive   [19]
  Software Archive   [4]

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