Unhappy with their lack of control over the products they had worked on, Richard Altwasser and Steven Vickers left Sinclair research to form Jupiter Cantab in (I think) 1982. Previously the pair had worked on the Spectrum with Richard designing the hardware and Steven doing the ROM code and the Spectrum BASIC manual. Steven had also written the ZX81 ROM code using bits of the ZX80 code that had been written by John Grant at Nine Tiles Software.

Their only machine was to be different to the home machines of the day which all ran a form of BASIC. Theirs was to run FORTH, a programming language that was more unintelligble and difficult to learn than the popular BASIC but was much, much faster. The machine was released in '83 with a blistering 3.5mhz Z80 CPU and a whopping 3K of RAM.

Similarities to the ZX80 are obvious; even the design of the case and PSU are identical. JC's only diversion was the use of a 'dead flesh' keyboard instead of the ZX80/81 membrane type......the case though, is a lot flimsier than the ZX80. The Ace was marketed in the US as the (slightly slower because of the different screen refresh rate) Jupiter Ace 4000 but failed to catch on there in much the same way as it did over here; it's complex language and mono graphics meant it fell by the wayside in comparison with the Spectrum and other machines of the day. Jupiter Cantab ceased to exist in 1984 with Steven going to the Open University as a lecturer and Richard moving to Germany where I believe he still is.

All the remaining Ace stocks were bought by Boldfield Computing Ltd, who continued to support the Ace for over a year until finally giving up the ghost and selling the whole lot in bulk; what happened to the machines that were left at this point is something I haven't managed to find out yet.

*update* courtesy of Tony Duell:

"AFAIK most of the complete ACEs were sold by Boldfield. They had a few
'special deals' to students where they threw in a lot of games tapes, etc
(how do you think I ended up with the games ;-)).

In the end, the remaining inventory of parts were sold off at low prices,
some of them as 'grab bags'. I bought at least one such bag/box, and
ended up with more games tapes, a spare PSU, a couple of extra RAMpacks, etc.

More specifically, there was certainly a deal for students at Churchill
College [1] in Autumn 1985. I think it was around \pounds 40 (\pounds
39.95???) for the machine, 16K RAMpack, cables, PSU, and a lot of games
tapes.

[1] Being at a different college, I got a friend of mine at Churchill to
order one for me.

I think the bits were sold off in the summer of 1986, but I am not
_certain_ about that.

A few years ago I met the chap who'd bought the rights to the ACE
firmware. I obviously can't speak for him, but he struck me as a true
hacker (I met him at a talk I was giving on the PDP11/45 -- non-hackers
don't normally come to talks about processor microcode...). I would
therefore be suprised if he had any objections to reasonable hackish use
of the firmware (such as keeping backups, etc)."

It remains though, as What Might've Been, in much the same way as the Enterprise 64......

Update 12/04/05 - OK I've had these for longer than this but I've been slow in updating! Courtesy of Alex Lindsay comes 2 Aces in the postage-style box, a bare motherboard, boxed Pacer 16K RAM pack, Ace User magazines, many tapes and a boxed WH Smith Data Recorder! Many thanks Alex :D

Ace with PSU and demo tape sheet.
Ace, complete with 16K RAM pack and PSU
2 Aces from Alex Lindsay - thanks!

Don't they make a lovely pair?
Running the Demos :)

Grant Searle's Build Your Own Ace hardware page