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back to article The Jupiter Ace is 30

The Basic programming language, although present in many different dialects, was the lingua franca of early 1980s home computers. One machine dared to be different: Jupiter Cantab's Jupiter Ace, a small unit that spoke Forth. It first went on sale 30 years tomorrow. Forth was conceived by Charles Moore, a computer scientist …

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Takes me back..

I always wanted one, but got a book on Forth, describing how to write it.

Over a sleepless weekend, I managed to get it running on a CP/M machine (8085). A lot of Forth is written in Forth, only had to write the primitives in assembler, so it wasn't too big a job - whole thing easily fitted on a 5.25" floppy, including CP/M itself.

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I.

Want.

My.

Childhood.

Back.

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Anonymous Coward

Me too. It's funny, but with hindsight just think what you could achieve.

I wouldn't bother with buying a machine at all but would be on the phone to Motorola blagging some 6089 samples and building something from scratch. As these stories demonstrate, you really could put something together on the kitchen table and have yourself a functional machine in a reasonable about of time.

(It would also be a good opportunity to get the open source ball rolling earlier. Not sure how the logistics of that would have worked though. Perhaps persuading universities to host public dial-up servers?)

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Pint

So.

do.

I.

Where the hell did they go?

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Really???

"Ten times faster despite running on the same Z80A processor that was found in the Spectrum and being clocked to 3.25MHz, eight per cent lower than the Spectrum's 3.5GHz."

You know, I'm pretty sure that 3.25Mhz is more than 8% slower than 3.5Ghz, but I don't remember my Speccy being faster than my PC! ;-)

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Re: Really???

It wasn't talking about the hardware being faster but the programs when running.

Forth executes much faster than Basic, just as machine code runs much faster than either on the SAME machine.

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Re: Really???

I think you're missing the glaring error I was making a joke out of in the article!

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Facepalm

Re: Really???

"It wasn't talking about the hardware being faster but the programs when running."

Take a closer look at the units used.

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Re: Really???

Indeed... I really didn't think you could overclock a Z80 into the gigahertz like that.

Those things really were cooking!

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Happy

Best investment I ever made.

Bought one some time in the '90s for a tenner, sold it on eBay recently for something over £300. Better return than any of my supposed pension investments.

GJC

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Re: Best investment I ever made.

You beat me to it. I bought a bunch second hand (along with sinclairs, dragons, vic20 etc). First tiem I sold some I was getting loads of emails every day asking to close the auction and sell immediatly (before buy now came along), lowest was around £225, highest one went for £650 but that was in near new condition, had a ram pack + a bunch of add on circuit boards and parts. I Keep watching the classifields but never seen one for many years.

Only got a zx81 and sinclair printer left :-( My new collection is aging sun and sgi boxes, sun pizza boxes make great foot rests.

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Unhappy

Re: Best investment I ever made.

"Bought one some time in the '90s for a tenner, sold it on eBay recently for something over £300. "

I get seriously annoyed with people who have done that.

Why?

Because I had quite a few of the old home computers in the early 90s, and eventually either dumped them, gave them away, or sold them for what I thought they were worth at the time - ie next to nothing.

BAH!

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Happy

Re: Best investment I ever made.

Well, you can't really blame us for your lack of foresight :-)

I was buying up a whole bunch of different stuff, as I wanted to have them to play with later on in life. Got all sorts of machines, mostly for a tenner - to the point where the TLA GST was coined on some systems, for "Geoff Standard Tenner" as a unit of currency.

Twenty years on, I realised there was no point in having a loft full of machines I wasn't getting the time to even look at, and decided to sell them on to people with more spare time and enthusiasm than I had. I was quite surprised by what some of them fetched.

GJC

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Re: Best investment I ever made.

Lesson to be learned! Buy Nokia Lumias!!! Lovely Jubbly, be worth a mint in a Flop^Wfew years time.

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Anonymous Coward

Re: Best investment I ever made.

me too - had dragons, color computers, IBM PC-XT, Jupiter Ace and god knows what else - sold off for a fiver each in the late 80s, when I got a 386 running windows 3.0. the money I threw away....

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Anonymous Coward

I do enjoy reading these mini epitaphs for the British computing industry. I am wondering if we are going to be treated to one on the Oric 1 in due course? ISTR that effort had the obligatory interesting Cambridge-based back story and stellar demise. Oh, and it came with Basic and Forth.

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It came out of Tangerine.

I worked closely with Barry Muncaster and his team. He made his money making meters for taxis. I used to write articles and the problem page for Oric Owner.

I also helped debug the version 1 ROM (actually and eprom in the early versions)

Shame the 6502 faded away. It had brilliant instruction set.

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Re: It came out of Tangerine.

Excellent stuff! I had an Oric at primary school age. I remember my Dad coming home one day with a copy of the v1.1 ROM burned onto a couple of EPROMs. I guess someone at work must have had a new Atmos and let him have a copy of the ROM image somehow. It absolutely transformed the machine. I took the old EPROMs to school subsequently to show to the awe of the children (and confoundment of my teacher). "You can see the actual microchip through the little window!"

The 6502 and its beefed up successors are still very much alive inside of various ASICs. I bought a little photo frame a while ago which contains a very standard 6502 augmented with JPEG decoder hardware, SPI flash and USB interface.

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Happy

@david

Don't be too downhearted for the 6502 will actually make a comeback in the distant future, serving as the CPU of Bending units.

(It's in the episode of Futurama where Fry is looking inside cans of Slurm with an X-Ray. He shines it on Bender's head and clear as day, there's a 6502 chip in there. I always wondered about the reference.)

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Re: @david

the 6502 lives in glorious technicolour: http://www.visual6502.org/JSSim/

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Happy

Re: It came out of Tangerine.

Didn't really fade away, it metamorphosed into the ARM 1, with the help of a few brilliant engineers.

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I loved my ACE. Never made it do anything useful but I still loved it.

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Childhood 2.0

The biggest achievement for the Jupiter Ace was that everyone wanted one once the company had gone bust and I missed my chance too. The nearest I could get was the Nottingham Microcomputer Club's single Jupiter Ace which would be out on permanent loan with a waiting period as long as a Sinclair delivery schedule, so when I finally got the chance I spent a happy homework-free couple of weeks ploughing through the manual; cramming my head full of its Forthy goodness and mind-blowing concepts.

A brilliantly clever machine flawed only by its tame monochrome graphics and glitchy keyboard driver (the rubber keyboard is actually fine, it's the firmware that's at fault).

Aaaaah, and it says it all that Ace's are practically just as unobtainable now; if only there was a similar 8-bit Forth computer you could buy today; we could all reclaim our childhoods ;-)

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Re: Childhood 2.0

Have you seen the FIGnition? https://sites.google.com/site/libby8dev/fignition/

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Vic
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Re: Childhood 2.0

> if only there was a similar 8-bit Forth computer you could buy today

Well, not exactly 8-bit, but you can do 16.

My customer gave me a couple of MSP430 Launchpads this week. Apparently[1], they can run Forth. And they're four quid a pop.

Vic.

[1] I've not actually had a chance to turn on one yet...

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I saw a complete Ace only once

But after the company went bust - long after, perhaps 1985 - I obtained from somewhere a handful of Jupiter motherboards, unpopulated, and built a couple up from scratch. I already knew Forth from a Tangerine system (and incidentally a Z80 CP/M system which I used as a front end for the Tangerine) so talking to it was no problem.

There must be dozens of us old fogies on El Reg who grew up when if you wanted a computer, you sat down and designed the damn thing, built it, and debugged it... or if you had a basic kit, you designed all the add-ons like video cards and storage.

More of these old memories, please - I'm waiting for your retro-review of the Amstrad 1512, the computer that the Open University guaranteed would last my entire degree course! (Er, it didn't.)

(So here I am today having just spent a month replacing an existing Z80 system with a PIC!)

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Re: I saw a complete Ace only once

Being an "old fogey" - proud of it, too, blowing fuses in proms in 44-bit wide microcode to make a spectrum analyser (Nicolet 440). Youth of today. Don't know they're born.

(Finishes pint, gets on bike, rides 100 miles to lick t' motorway clean.)

Luxury....

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Test

It was great for writing programs to test stuff. I forget what we connected it to. They should have had a DIN module version from the beginning with an expansion I/O backplane. That would have been a niche market but successful.

I gave my personal one away circa 1973. The Pac-Man game ran well. Being able to use any number base was "unusual". Base 32 anyone?

Forth and of course HP RPN calculators are a bit Marmite.

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Unhappy

Re: Test

Late 1983 ... not 73 (when do we get an edit feature?)

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Heh! Marmite...You either love it or hate it!

Still got an early HP RPN calculator. HP35. Gotta find out how to stick some new batteries in it, and hook up a charger of sorts.

Frikking hell, just found out the thing's 40 years old!!!! Definitely gonna work on firing that baby up. If my Sinclair Scientific still works, I've no reason to suspect this baby won't!

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Re: Heh! Marmite...You either love it or hate it!

Still using my 1985 HP11C. Was irritated last month as I had to change the batteries for the first time...

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Re: when do we get an edit feature?

it's called preview

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Happy

I still have mine

Or rather, my brother's. We rehoused it in a metal box with a new keyboard and installed it under the telly to manage our video tape library. It worked well unless it got unplugged and we had forgotten to back things up to tape. But that happened rarely...maybe once a week.

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Vic
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Re: I still have mine

I've still got mine, too. And it works.

It was not quite my first foray into Forth, but probably took more pounding than the Tiny Forth I started with.

And 30 years later, I'm still writing Forth. And getting paid for it these days :-)

Vic.

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Bod

WHSmiths

Looked cool in WH Smiths next to the others but I could never work out how to make it flash and scroll rude words in Forth.

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Get one

If you know a little Forth, it's worth grabbing an emulator (there's a whole bunch on http://www.jupiter-ace.co.uk/emulators_unix.html) and giving it a go. It's a humbling experience. Where a ZX81 feels like a toy, an Ace with 3kB feels like a real computer --- something you can actually genuinely write useful programs in. Their Forth, extended to allow words to be redefined, provides one of the most minimalist yet real development environments I've ever seen, providing both low level and high level features at the same time.

The implementation was a work of art, too, using all kinds of strange Z80 features to achieve maximum code density. There's a disassembly here: http://www.wearmouth.demon.co.uk/ace.htm If you want a (now rather old fashioned, but still useful) Z80 Forth implementation, you could do a lot worse.

And if you don't know any Forth, LEARN SOME. It's pretty much useless in real life, but knowing Forth will make you a much better programmer in other languages. And it is the go-to language for really low-end embedded devices.

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Vic
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Re: Get one

> extended to allow words to be redefined

Indeed. You can use that stunt to write recursive words too - although that's not necessarily a good idea if you've only got 3KB of RAM...

Vic.

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Anonymous Coward

Vickers' ZX Spectrum manual remains one of the best computer books I've read, and probably the one that taught me the most.

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Forth was a lot of fun.

I thought of buying one of these because it ran Forth.

I'd been introduced to Forth by a lecturer at college who thought I'd find it interesting after I'd written a program to do framework stress analysis on a programmable calculator. He had it running on an Excidy Sorcerer and mate with rich parents had one. The Excidy had half its character generator in RAM, so you could get heady high res graphics (640x240ish I think) by carefully redefining characters and so I quickly wrote a copy of Space Invaders in Forth.

Ah... that takes me back.

Had my HP85 out yesterday, the eldest is off school and though it was time for him to have a chance to write some software.

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Forth Vs Machine Code

FORTH may have been great at being faster than BASIC (if you didn't factor in all the extra time needed to learn Forth!), but any computer geek at the time would have been looking towards machine code.

The outstanding "Spectrum ROM disassembly" and David Webb's "Supercharge Your Spectrum" were the two treasured books to have & inspire you and are still on my bookshelf today.

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Re: Forth Vs Machine Code

Indeed Sir, which is why I learnt Z80 Assembler...

... did part of my O-Level Computer Studies project in it....

... learnt 68000 Assembler on the back of that knowledge, but never quite wrote an Atari ST, or Commodore Amiga Program...

... which also meant that when I was working on a financial company's DEC-VAX system (early 2000's I kid you not) that had Macro 32 Assembler that needed fixing, I could...

... and I now (part time) tutor ARM Assembler at the University of ...

Oh The ACE? Bought a pair of books on Forth (Language Library's Fundamentals and Techniques, I can see them in my bookshelf!), but never bought one in the end. Shame, would have been an interesting experience. However I did use Forth, beats me what it was on.

Anyone remember 'Fifth' by some chap for the ZX Spectrum, was that related in anyway?

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JQW

Re: Forth Vs Machine Code

Fifth had nothing to do with Forth. Instead it was a BASIC extension that used REM statements to host new commands. As Fifth was for writing games, the extensions were mainly for handling sprites and sound effects.

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All this talk of Forth...

...means I am having a very good day today!

<--- check the handle :-)

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Some Forth:

A loop that counts from 0 to 99:

: 0to99 100 0 DO I . LOOP ;

Simple, eh?

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Re: Some Forth:

I'm more impressed by NEXT in 6809 assembler - 4 bytes !

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Coat

Re: Some Forth:

Shurely NEXT is 4 bytes in any 8-bit code...?

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Re: Some Forth:

No, most 8 bit forths need to JSR which , of course, can be a variable length routine depending on processsor. With the 6809 the actual code to implement NEXT is 4 bytes and can be put in-line saving the sub-routine call at the expense of slightly longer code

LDX 0,Y++

JMP [0,X]

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Re: Some Forth:

Sorry, should qualify, that's for indirect threaded code as per most early 8-bit Forths

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Re: Some Forth:

I think I managed to get NEXT down to one instruction on the ARM --- ldr pc, [ip, #4]!, maybe? It's been a very long time.

I was deeply impressed by Forth, from its design to its philosophy to the utterly minimalist implementations. Can I actually do anything useful with it? Can I hell. I'm far too fond of things like type checking, and variables, and syntax that can be checked at compile time, and little stuff like that.

An HLL that compiles into Forth would be a very nice thing to have, but producing good code from Algol-alikes like C would be hard because of differing stack semantics. JVM bytecode, perhaps --- it's already stack-based, after all...

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Facepalm

4E 45 58 54

4 bytes. (Mostly) platform independent.

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