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80386DX ISA single board microcomputer

alexandrugroza.ro

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Re: 80386DX ISA single board microcomputer

#31

Post by jazzyjackson »

timonoko wrote: post #27
hulitu wrote: post #21

Earlier quoted context omitted.

Why not "some 1990 beige box from China" ? Do you think this is not interesting enough ? An 1972 computer is more mecanically challenging . And finding ICs could also be challenging because some are not produced anymore at least in the west. Finding SW is also a challenge. In the end is a question of mostly time and component availability.

I just threw 1988 turbo-button computer into garbage. I kept in the closet for 30 years, because it was not mine, and I excepted the owner will come any time and collect it. Now he is dead and I do not believe in ghosts.

doing your part. the only reason any vintage computer becomes valuable is that most of them get tossed in the trash. the kids in the year 2076 are going to love turbo buttons. Chinese factories manufacturing parts for American computers, who could imagine!

Re: 80386DX ISA single board microcomputer

#32

Post by toast0 »

timonoko wrote: post #27
hulitu wrote: post #21

Earlier quoted context omitted.

Why not "some 1990 beige box from China" ? Do you think this is not interesting enough ? An 1972 computer is more mecanically challenging . And finding ICs could also be challenging because some are not produced anymore at least in the west. Finding SW is also a challenge. In the end is a question of mostly time and component availability.

I just threw 1988 turbo-button computer into garbage. I kept in the closet for 30 years, because it was not mine, and I excepted the owner will come any time and collect it. Now he is dead and I do not believe in ghosts.

There's people who are looking for that kind of stuff. If it's not too late, it would be worth posting it for free (or whatever) on your favorite local market.

Re: 80386DX ISA single board microcomputer

#33

Post by hmrr »

yitchelle wrote: post #19

It is truly amazing that one person can bring up a 386DX board system. It is true that there are tons of docs available, but still to bring everything together and to get it running is truly amazing. The team size at any of the PC OEMs doing a 386DX design when it was the state of the art would be at least 25 engineers and managers, easily. Congrats to Alexandru for hitting this out of the park.

My father used to import clone PC stuff from Taiwan. The guys running these ops were surprisingly small usually. Some of the original ISA graphics cards including the weird CEG (anti aliasing ones) had 3 guys running the entire outfit. The guy writing the software was stuffing boxes in his lunch break and there were no managers. Even the case design companies were one man outfits with all the actionable stuff contracted out. It was remarkable.

Re: 80386DX ISA single board microcomputer

#34

Post by guerrilla »

flyinglizard wrote: post #7

Awesome project, although I personally can’t identify with putting such effort into reinventing the past instead of making something new. I suspect different people live in different periods. I’ve known people who always dwell on the past, those who are preoccupied with the future and those who are in the present and not overthink too much in either direction.

Because it's possible. Bringing up more advanced CPUs alone and with hobbyist tools is borderline impossible. Nothing revolutionary changed (Sorry Pentiums) until the Opteron, so you're covering an entie era by doing this and learning a ton that applies even today.

I dislike the premise of your question though. There's no reason it need to be economically useful. People can just do things thy love and enjoy.

On top of that, this question is like asking why learn finite automata, why not just jump straight to Turing machines and trying to solve P=?NP. No, that's nonsense obviously and you gotta walk before you can run.

Re: 80386DX ISA single board microcomputer

#35

Post by tecleandor »

roywashere wrote: post #13

> And there is the original Duke Nukem (DN1, DN2, and DN3) which I always would have liked to have the ability to turn down the volume for. Playing without sound effects was no fun and with sound effects was disturbing for the other people in the house. Is there a good reason that most XT/AT era computers had no volume control for their PC speaker? I always wondered. My dad's XT had an incredibly loud speaker, I alwa…

I had an Amstrad PC1512 I will always remember because it had a volume control. It had some sort of powered speaker, so you could turn it up absurdly high, or lower the volume down reasonably (even switching it off)

This is not the exact model, but you can see the volume control here:

https://computers.popcorn.cx/amstrad/pc2086/pc2086-02.jpg

Re: 80386DX ISA single board microcomputer

#36

Post by guerrilla »

I'm doing the much easier version of this with the 8086 right now. After having learned how to do that, I find it hilarious that I considered starting with a 386SX. This is a seriously difficult project for a hobbyist. I'm so glad someone did this though because now I can just kit and mod it and skip the designing.

Props on going for a full 32MB of RAM. No 16650 UART though? I'd add that.

Overall, congratulations!

Re: 80386DX ISA single board microcomputer

#38

Post by gruturo »

ahefner wrote: post #5
balls187 wrote: post #4

I didn't realize Intel switched the meaning of DX/SX between their 386 and 486 CPU's.

How so? SX was always the crappy version.

True, but SX used to stand (officially? dunno) for Singleword Xchange, as it had a 16 bit bus. DX was Doubleword Xchange, hence 32bit bus.

Then in the 486, the bus was always 32-bit (at least from Intel. I have a faint memory of Cyrix 486SLCs with a 16bit bus), and now the SX-DX indicated the presence of an integrated FPU instead.

Bonus: the 80487 was not just an FPU. It was a full 486DX which just disabled the main CPU and did all the work, and of course had an FPU.

Re: 80386DX ISA single board microcomputer

#39

Post by oso2k »

pkaye wrote: post #25
roywashere wrote: post #13

> And there is the original Duke Nukem (DN1, DN2, and DN3) which I always would have liked to have the ability to turn down the volume for. Playing without sound effects was no fun and with sound effects was disturbing for the other people in the house. Is there a good reason that most XT/AT era computers had no volume control for their PC speaker? I always wondered. My dad's XT had an incredibly loud speaker, I alwa…

It was just a single pin on the timer chip connected to a buzzer so you could generate a square way at a certain frequency.

But you could do a bit more. Here’s a DOS golf game that did.

https://m.youtube.com/watch?v=hMPb1UlSRpY

Re: 80386DX ISA single board microcomputer

#40

Post by joakleaf »

anyfoo wrote: post #26
hulitu wrote: post #14

Earlier quoted context omitted.

You can run Windows 3.1 which has a GUI more advanced than win 10 GUI. But 32 MB RAM ? Is there any Win 3.1 app which can use so much RAM ?

Probably not so much. Most of Win 3.1 is actually still 16bit even in Protected Mode (unless you count win32s which came much later), so everything over 1MB cannot even be addressed directly. While you can probably come up with something that makes use of the 32MB under Win 3.1, that would likely be rather artificial and not very typical of what was happening back in the day, not just because 32MB was considered abso…

Protected mode using 16 bit segment:offset addressing could use more than 1 MB of memory.

The segments were 64K, but the base address of each individual segment was defined in a descriptor table and could point to anywhere within 24-bit addressable memory space on the 286 and 32-bit on the 386.

So the 286 was limited to 16 MB of ram in 16-bit protected mode. The 386 not so.

Incidentally, I had a 286 that was happy to use all the 4 MB of memory it had when running under Windows 3.1.

I remember using Turbo Pascal for Windows, and being amazed that I could allocate more than 640KB — albeit in 64K segments.

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