XACE

Les Pounder nips back to the early 80s and pays homage to a home computer that sold less than 6,000 units, despite its go-faster stripes!

Credit: https://github.com/lawrencewoodman/xAce 

OUR EXPERT

Les Pounder is associate editor at Tom’s Hardware and a freelance maker. He blogs about hacks and makes at bigl.es.

QUCIK TIP

To see the contents of our word (subroutine) we need to use the LIST command. In BASIC we’d provide a line number, but with Forth we have to pass the command the name of our word. For example, LIST lxfloop.

We go back to 1982 to discover that not all home computers came with BASIC. The Jupiter Ace, from the Cambridge-based Jupiter Cantab Limited computer company was an oddity of the era. The Jupiter Ace looked like a cross between a ZX81 and a hot rod and we quite like that. The design of the Jupiter Ace was down to its creators Richard Altwasser and Steven Vickers, who had previously been part of the ZX Spectrum design team. The Jupiter Ace had 2KB of dedicated video RAM, which offered a performance boost over the ZX Spectrum.

Packing a Z80 CPU running at 3.25MHz and a minimum of 1KB of RAM, the Jupiter Ace was sold for £89.99 in 1982 (approximately £277.20 adjusted for inflation). This was much lower than the Commodore 64’s £350 (an eye-watering £1,078 in today’s money) price tag.

Accessories for the Jupiter Ace included 16, 32 and 48KB RAM packs, replacement keyboards and external storage devices. Most users saved their programs directly to cassette using tape recorder, which was a common technique of the era.

Instead of running a BASIC interpreter/operating system we’re presented with Forth, a language that we shall get to grips with later (see LXF276 for more on programming the Jupiter Ace in Forth).

The Jupiter Ace wasn’t a big seller, with a reported 5,000 units made and even fewer of the Jupiter Ace 4000 being manufactured at around 800 units, which featured a stronger injection-moulded plastic case. This computer may not have had the high sales of Sinclair’s and Commodore’s machines, but it has a special place in the hearts of coders who cut their teeth with Forth.

Emulating a Jupiter Ace

The best Jupiter Ace emulator that we could find for our Kubuntu install was xAce, but bear in mind that we experienced a few bugs while exploring the program. We started by downloading the source files from the project’s GitHub page. Git users can either clone the repository from https://github.com/lawrencewoodman/xAce or download and extract the ZIP file from https://github.com/lawrencewoodman/xAce/archive/refs/heads/master.zip.