The Jupiter ACE was a British home computer, which was released in 1982 by a company called Jupiter Cantab. The company was formed by Richard Altwasser and Stephen Vickers, the former had worked on the hardware of the Spectrum at Sinclair while the latter had worked on the BASIC ROM of the same machine at Nine Tiles, the company subcontracted for the task.

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 (1500 baud cassette tape), as was standard at that time. The Jupiter Ace was built around the Z-80A CPU, which ran at 3.25MHz. The machine came with 8K ROM and 3K RAM, expandable to 49K. 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 meagre 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 high prices as collectors items.

Physically the machine is made out of very flimsy plastic, and like the ZX80 before it, is held together with tiny plastic rivets. Externally there are two expansion sockets, one for extra RAM (a 16K model was produced, but is extremely rare today). The other slot would have been for disk drives or printers if any had been produced. On the right hand side of the machine there is a RF socket, and the ear and mic socket, and on the left hand side there is a power socket.

The Jupiter Ace originally sold for £89.95.

A refined version of the machine followed a few months after. The Jupiter Ace 4000. It had a sturdier case, a monitor socket for composite, and came bundled with the 16 Ram Pack.

This example in our collection comes with a 16k RAM pack, power supply, cables, Forth programming manual and two tapes: Jupiter Tool Kit Monitor and Five programs for the Jupiter Ace including Music, Banner, Worms and Lunar Lander.
 
This unit was very kindly donated by Mr Alan Leeson

Manufacturer: Jupiter Cantab
Date: 22nd September 1982

This exhibit has a reference ID of CH1332. Please quote this reference ID in any communication with the Centre for Computing History.