Two of the Sinclair ZX Spectrum’s designers went on to form Jupiter Cantab, and develop a small low-cost 8-bit microcomputer called the Jupiter ACE. In 1982, they released their creation, and advertised it in a similar way to Sinclair’s computers.
The ACE was comparable in size, appearance and hardware specification to the Sinclair ZX range.
It had the following things in common with the Sinclair ZX81:
- 8 KB of ROM.
- 1 KB of RAM.
- Monochrome video output.
- Z80 microprocessor clocked at 3.25 MHz.
The ACE was a little different by having an additional 2 KB of video RAM. That’s why it’s sometimes described as having 3 KB of RAM in standard form.
The ACE also had some things in common with the ZX Spectrum:
- Moving-key keyboard (rather than a ZX81-style membrane one).
- Sound generator.
- Cassette interface which ran at 1500 bps.
Sadly, the sound generator was fairly primitive. Rather than using a programmable sound chip like the Commodore 64 or BBC Micro, it just had a simple 1-bit output. That made it similar to the Spectrum or Apple II, by requiring CPU time for every pulse.
The thing that made the ACE particularly interesting to me was its choice of built-in programming language — FORTH. At the time, the majority of popular microcomputers were supplied with the BASIC programming language as standard. The use of FORTH was supposed to make the ACE ten times faster, and more memory-efficient.
Limited Market Appeal
In reality, most home computers were used for gaming, and most games were written in machine code. That made the choice of language stored in ROM irrelevant — the hardware specification was the main thing that mattered. And that was an area where the ACE was not very strong.
With no colour graphics, a primitive sound generator similar to the Spectrum, and just 1K of RAM as standard, the ACE did not have much to offer the mass-market.
It’s a pity that the designers didn’t give the ACE colour, and perhaps a sound generator chip. That might have helped give it more appeal — although the price would have no doubt gone up a little.
Although I never owned or used a Jupiter ACE in the 1980s, its use of FORTH intrigued me. The ACE seemed quite a quirky and unique machine. For that reason, I would like to get my hands on one at some point.
Do you have memories of using the Jupiter ACE?
Share your thoughts in the comments section below.