142 ms·

I started with a ZX81, and wrote and sold (one copy!) of a... Xevious clone, called "ZXevious". Perfect name, heh? All assembly, cross-compiled from another mac

by 10ren 16y ago

I started with a ZX81, and wrote and sold (one copy!) of a... Xevious clone, called "ZXevious". Perfect name, heh? All assembly, cross-compiled from another machine, many simultaneous objects on screen, and I even emulated (or tried to) the brand new Macintosh interface that had just come out, in the "GUI" for selecting the keyboard layout. The ZX81 BASIC (and "OS", such as it was) was written by Steve Vickers, and everything fitted into an 8K ROM. I have always been impressed by this guy's work. The whole unit had only 4 chips (ROM, RAM, CPU and a custom chip). Scroll done for a photo: http://oldcomputers.net/zx81.html http://oldcomputers.net/zx81.html Steve Vickers went on to create the Jupiter Ace (with the main ZX81 hardware guy), which had similar hardware, but instead of BASIC, it had Forth.

arethuza 16y ago
I really wanted a Jupiter Ace, but had to do with the Sinclair and Apple devices at school. I had read a bit about Forth and thought it sounded rather cool. I've been fascinated by RPN languages ever since - even managing to have great fun doing interactive PostScript development on slightly more expensive kit.
- torpor 16y ago
  I had an Oric-1 in those days, but really wanted a Jupiter Ace as well .. there was something so sexy about that machine, for some reason.
  - arethuza 16y ago
    Here's your chance: http://cgi.ebay.co.uk/Jupiter-Ace-Computer-/290440498106?cmd=ViewItem&pt=UK_VintageComputing_RL&hash=item439f9a4bba http://cgi.ebay.co.uk/Jupiter-Ace-Computer-/290440498106?cmd... I have to say that it doesn't look quite as interesting as it did when I was 16.
  - deadsy 16y ago
    I had similar feelings of lust. A couple of years ago I satisfied them by pulling the rom binaries off the web and writing a z80 emulator (in python) that could run them. Conclusion: a) don't expect to write fast cpu emulators in python. b) the jupiter ace failed because the hardware missed the boat. It was basically a zx81 running Forth, released at a time when the zx spectrum was wowing everybody with its color. It's probably the case that the use of Forth didn't give it any great advantages over BASIC given that the underlying machine was so incapable.
    - 10ren 16y ago
      Forth claimed to be 5 times faster than BASIC http://en.wikipedia.org/wiki/Jupiter_Ace http://en.wikipedia.org/wiki/Jupiter_Ace Everyone went to assembly if they wanted speed. I think Forth requires more thinking than BASIC (at least, of a mathematically flexible kind).
torpor 16y ago
I'm a huge fan of Xevious and have it on my Pandora gaming console as a stock-standard go-to for when I need to shoot something. I'd love to see ZXevious - any chance you've still got a copy somewhere? We Pandora fanboix have lots of emulators in our pockets these days ..
- 10ren 16y ago
  Thanks! Unfortunately, I have no idea where it is (and it would be on tape... transferring that would be another issue). I have fond memories of it - but of the writing, not the playing. :-)
RichClaxton 16y ago
I also started with a ZX81, I still have all the docs that came with it, the ZX81 got binned while I was away at University to my horror. I used to play 3D Monster Maze on it all the time.
rbanffy 16y ago
> The whole unit had only 4 chips (ROM, RAM, CPU and a custom chip). It always amazes me why would anyone need more than that. Well... Memory could be an exception - a single memory chip is limiting - but the rest is doable. PCs are ugly overcomplicated things.
- a1k0n 16y ago
  Well, the C64 for instance had complicated enough video and sound to warrant separate devices, plus a bunch of peripheral ports (joysticks, etc) and then you need address decoding logic to support all of that. It all depends how much of it you can bundle up into your "custom chip". The first Apple had no custom chips and generated video and sound with extremely clever arrangements of standard logic gates.
  - rbanffy 16y ago
    The later incarnations of the C64 had a much reduced chip-count in relation to the first ones. http://www.commodore.ca/products/c64/commodore_64_motherboard_1982_1992.jpg http://www.commodore.ca/products/c64/commodore_64_motherboar... and http://www.commodore.ca/gallery/hardware/c65.jpg http://www.commodore.ca/gallery/hardware/c65.jpg Even if you don't get to 4 chips, a simple and elegant design is very desirable. And, in the case of PCs, quite impossible.
    - ido 16y ago
      And as history shows, doesn't matter much - users don't care how many chips are in their computers. It just has to be cheap and run the software they want to use.
      - rbanffy 16y ago
        Engineers like me care. I find it disturbing that my computer has, somewhere inside its sleek and modern body, a complete IBM 5150, with its ISA bus, serial ports, real-time clock, keyboard micro-controller (with that horrendous A20 hack so that the 286 it can emulate can switch between user and whatever mode OS/2 1.0 would need to run) and CGA display adapter ready to boot up PC-DOS from something it thinks is an MFM hard disk. The only thing missing is Microsoft's BASIC burned in ROM. It's offensive. Really. I have a collection of 80's and 90's computers. No computer in the collection is as inelegant as the IBM PC and its clones. Many of them (original Mac, Apple II - despite the chip count - Ataris) are absolute works of art. Sheer elegance in their simplicity.

by 10ren 16y ago

arethuza 16y ago

I really wanted a Jupiter Ace, but had to do with the Sinclair and Apple devices at school. I had read a bit about Forth and thought it sounded rather cool. I've been fascinated by RPN languages ever since - even managing to have great fun doing interactive PostScript development on slightly more expensive kit.

torpor 16y ago
I had an Oric-1 in those days, but really wanted a Jupiter Ace as well .. there was something so sexy about that machine, for some reason.
- arethuza 16y ago
  Here's your chance: http://cgi.ebay.co.uk/Jupiter-Ace-Computer-/290440498106?cmd=ViewItem&pt=UK_VintageComputing_RL&hash=item439f9a4bba http://cgi.ebay.co.uk/Jupiter-Ace-Computer-/290440498106?cmd... I have to say that it doesn't look quite as interesting as it did when I was 16.
- deadsy 16y ago
  I had similar feelings of lust. A couple of years ago I satisfied them by pulling the rom binaries off the web and writing a z80 emulator (in python) that could run them. Conclusion: a) don't expect to write fast cpu emulators in python. b) the jupiter ace failed because the hardware missed the boat. It was basically a zx81 running Forth, released at a time when the zx spectrum was wowing everybody with its color. It's probably the case that the use of Forth didn't give it any great advantages over BASIC given that the underlying machine was so incapable.
  - 10ren 16y ago
    Forth claimed to be 5 times faster than BASIC http://en.wikipedia.org/wiki/Jupiter_Ace http://en.wikipedia.org/wiki/Jupiter_Ace Everyone went to assembly if they wanted speed. I think Forth requires more thinking than BASIC (at least, of a mathematically flexible kind).

torpor 16y ago

I'm a huge fan of Xevious and have it on my Pandora gaming console as a stock-standard go-to for when I need to shoot something. I'd love to see ZXevious - any chance you've still got a copy somewhere? We Pandora fanboix have lots of emulators in our pockets these days ..

10ren 16y ago
Thanks! Unfortunately, I have no idea where it is (and it would be on tape... transferring that would be another issue). I have fond memories of it - but of the writing, not the playing. :-)

RichClaxton 16y ago

I also started with a ZX81, I still have all the docs that came with it, the ZX81 got binned while I was away at University to my horror. I used to play 3D Monster Maze on it all the time.

rbanffy 16y ago

> The whole unit had only 4 chips (ROM, RAM, CPU and a custom chip). It always amazes me why would anyone need more than that. Well... Memory could be an exception - a single memory chip is limiting - but the rest is doable. PCs are ugly overcomplicated things.

a1k0n 16y ago
Well, the C64 for instance had complicated enough video and sound to warrant separate devices, plus a bunch of peripheral ports (joysticks, etc) and then you need address decoding logic to support all of that. It all depends how much of it you can bundle up into your "custom chip". The first Apple had no custom chips and generated video and sound with extremely clever arrangements of standard logic gates.
- rbanffy 16y ago
  The later incarnations of the C64 had a much reduced chip-count in relation to the first ones. http://www.commodore.ca/products/c64/commodore_64_motherboard_1982_1992.jpg http://www.commodore.ca/products/c64/commodore_64_motherboar... and http://www.commodore.ca/gallery/hardware/c65.jpg http://www.commodore.ca/gallery/hardware/c65.jpg Even if you don't get to 4 chips, a simple and elegant design is very desirable. And, in the case of PCs, quite impossible.
  - ido 16y ago
    And as history shows, doesn't matter much - users don't care how many chips are in their computers. It just has to be cheap and run the software they want to use.
    - rbanffy 16y ago
      Engineers like me care. I find it disturbing that my computer has, somewhere inside its sleek and modern body, a complete IBM 5150, with its ISA bus, serial ports, real-time clock, keyboard micro-controller (with that horrendous A20 hack so that the 286 it can emulate can switch between user and whatever mode OS/2 1.0 would need to run) and CGA display adapter ready to boot up PC-DOS from something it thinks is an MFM hard disk. The only thing missing is Microsoft's BASIC burned in ROM. It's offensive. Really. I have a collection of 80's and 90's computers. No computer in the collection is as inelegant as the IBM PC and its clones. Many of them (original Mac, Apple II - despite the chip count - Ataris) are absolute works of art. Sheer elegance in their simplicity.