I didn't realize Intel switched the meaning of DX/SX between their 386 and 486 CPU's.
Then Intel released DX2 486s, which ran the core at twice the bus speed.
No one is good at naming things in our industry.
80386DX ISA single board microcomputer
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Re: 80386DX ISA single board microcomputer
#82Although this seems to be a 33MHz CPU, the 386DX40 was the first "decent" processor I had access to when growing up so was quite memorable for me. In my teenage years the PCs my brothers and I had access to were two 386DX40s each with 8MB of RAM and several hundred MBs of hard disk space (can't remember exactly, but pretty sure less than a GB). We really loved Blizzard's Warcraft II, which despite having a minimum re…
A little late but you could also have used the Crynwr plip packet driver to run IPX over the parallel cable avoiding the significant overhead of running Windows 95 on a 386 system.
Only about 25 years too late :D, but that would have been cool to know about.
It does make me think though about how I might have discovered such a thing at that point in time.
I don't think I even had internet at home then, I never used things like a BBS and later I was never big into forums either. So the only way I really learnt things was either through fiddling (which is how I found out about the parallel cable networking) or through word of mouth.
It also might not have occurred to me yet how to find answers on the internet and besides, there was no Google back then.
There also wasn't any local community I was aware of that was into these kinds of things. So I only learnt very limited amounts.
I guess I could have tried computing magazines which may also have helped, but I didn't have any real money then, and it's also possible that the options were very slim in South Africa anyhow.
Re: 80386DX ISA single board microcomputer
#83Earlier quoted context omitted.
Fifty years ago. EE school. TV lab. First day practicing TV repair. Two by two on high stools behind the open sets. Joe looking up from the schematic: "John, where is the high voltage?" John knows. Points his finger at the set ... and touch! I heard the zap and saw John and his stool tilt backwards. Flat on the floor. He was somewhat pale but otherwise ok.
And instantly a lot smarter!
Yeah, when his memory returned.
Re: 80386DX ISA single board microcomputer
#84Wow! Very cool project and very inspiring! I'd love to know more about hardware like this but I wouldn't know where to start.
Re: 80386DX ISA single board microcomputer
#85Earlier quoted context omitted.
"Interesting History" is just before your own time (of sentience). I would consider rebuilding 1972 computer a worthy task. But not some 1990 beige box from China.
I kind of wish I had my 1990 beige box, even though it was a hunk of junk even for the time.
It was the worst of times. You needed at least 50 Mhz to play MP3-files. Only rich people could afford that. And couple of years later you wanted to play DIVX-files and you needed 300 Mhz.
Re: 80386DX ISA single board microcomputer
#86I wonder, apart from having fun and scratching some nostalgia itches, what are the outcomes of this? Do any of the things learned by doing this project help in working with present day hardware?
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 ?
A 386DX actually has a full 32-bit address bus, so you can theoretically give it (almost, due to MMIO) 4GB of RAM. Memory testing might take a ridiculously long time, however, and I'm not sure if there's any stock BIOS that will handle it. All limitations that can be worked around, of course.
Re: 80386DX ISA single board microcomputer
#87Earlier quoted context omitted.
Fifty years ago. EE school. TV lab. First day practicing TV repair. Two by two on high stools behind the open sets. Joe looking up from the schematic: "John, where is the high voltage?" John knows. Points his finger at the set ... and touch! I heard the zap and saw John and his stool tilt backwards. Flat on the floor. He was somewhat pale but otherwise ok.
And instantly a lot smarter!
It's amazing how complacent we get.
Two times every day I duck under an electric gate that's fed by a 10kV (might be higher) low-impedance charger. Been doing it this way for years.
Then a few days ago, ducking under it as usual, I happened to be on a slightly higher part of the ground and my back touched it as I was wearing wet, muddy boots. And I was instantly reminded why the horses have learned to not get too close to the fence :-)
Re: 80386DX ISA single board microcomputer
#88This is an awesome project! There have been others who have made their own computers using as far as a 486 (https://news.ycombinator.com/item?id=26407783 ) but making it IBM PC compatible really takes it to the next level. The only thing that would make it more amazing is if he didn't use existing chipsets and implemented all the glue logic on an FPGA (like the aforementioned 486 board) or discrete TTL.
The Pentium was when Intel started to get too secretive, I think; there's relatively little of the low-level information that's needed to create hardware like this compared to previous CPUs. I believe modern PC designs are all entirely based on a reference design from Intel so if you could get access to one, it would be possible to make your own motherboard, but signal integrity and such are going to make the PCB layout much more difficult. That said, there are plenty of laptop schematics out there... and (although a group effort) some Chinese managed to make a custom motherboard replacement for a Thinkpad: https://news.ycombinator.com/item?id=15274644
Re: 80386DX ISA single board microcomputer
#89Earlier quoted context omitted.
I've always wondered why no one came up with cheaper / mass produced 386/486 SOCs; are there any still-valid patents preventing that or is it too much work when we have powerful & cheap ARM SOCs that can emulate them...
I also think it would be interesting to see how small, or how fast, you could make a standard 486 by applying modern manufacturing.
Intel did that with the Quark core. (Get the datasheet and compare with the 486 one. Some of the diagrams are identical, and I recall seeing one of the search/replace they did resulted in "QuarkDX" showing up.)
Re: 80386DX ISA single board microcomputer
#90This is absolutely amazing and beautiful work. Congratulations to Alexandru! BTW can someone clarify what's the benefits of building the computer as an ISA board?
Probably because he previously designed an ISA backplane to plug it into: https://alexandrugroza.ro/microelectronics/system-design/isa...