80386DX ISA single board microcomputer • Hacker News Board

Re: 80386DX ISA single board microcomputer

#51

Post by ido » Fri, Nov 19, 2021, 9:30 AM UTC

unixhero wrote: post #50

123pie123 wrote: post #47

These things remind me of one of my first jobs as a bench engineer 'trying' to fix PCs the vast majority of problems back then was the power supply and the vast majority of the issues with power supplies was burned out capacitors - easily fixable. for some bizaar reason one memory that also sticks out was the painful compatibility issues of putting seagate hard disks together with conner hard disks (IDE cables) also…

Good story! Everyone were correct about being afraid of opening CRT monitors. Repairing them is a whole other domain than PC electronics. A CRT ZAP from the cathode ray components can kill. That is not a place one should poke around trying to find solutions.

I wonder if I just got lucky in my youth trying to repair a mac classic II (at the time it was about 10 years old), or if the 9" CRT that must have not been turned on for years at that point didn't have enough of a charge?

That machine eventually lived and functioned perfectly for quite a few more years (ended up just needing a new HDD) until finally dying.

Re: 80386DX ISA single board microcomputer

#52

Post by agumonkey » Fri, Nov 19, 2021, 9:37 AM UTC

oso2k wrote: post #49

gigel82 wrote: post #30

Earlier 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...

386, 486 embedded chips were widely produced as SOCs but they’re embedded in places you probably wouldn’t look for them. Which is why they’re SOCs. :) 586 and semi 686 compatibles are still available in certain quantities. Today, a Pi0W could emulate anything up to a low end 486, Pi0-2W/CM3 could do about 486DX-100/low end Pentium. https://en.m.wikipedia.org/wiki/List_of_former_IA-32_compati... https://m.youtube.com/…

Aren't there 486 class cpus in space ? I thought they made radiation hardened designs that were sufficient for their needs.

Re: 80386DX ISA single board microcomputer

#53

Post by slim » Fri, Nov 19, 2021, 9:39 AM UTC

hulitu wrote: post #14

DeathArrow wrote: post #9

I 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 ?

  Is there any Win 3.1 app which can use so much RAM ?

Maybe someone will start a new software project targeting the platform. That would be the second most interesting project.

Re: 80386DX ISA single board microcomputer

#54

Post by liendolucas » Fri, Nov 19, 2021, 9:49 AM UTC

Wow, that's something impressive! I'd really pay for a device that can run DOS games from that era (the golden era of video games). Yeah, we do have emulators and all that, but having a real full fledged x86 retro computer running old stuff is cool. I don't know about the author but I think he is in a very good position to push this further and make it a product, I'd definitely buy one!

Re: 80386DX ISA single board microcomputer

#55

Post by formerly_proven » Fri, Nov 19, 2021, 9:50 AM UTC

ido wrote: post #51

unixhero wrote: post #50

Earlier quoted context omitted.

Good story! Everyone were correct about being afraid of opening CRT monitors. Repairing them is a whole other domain than PC electronics. A CRT ZAP from the cathode ray components can kill. That is not a place one should poke around trying to find solutions.

I wonder if I just got lucky in my youth trying to repair a mac classic II (at the time it was about 10 years old), or if the 9" CRT that must have not been turned on for years at that point didn't have enough of a charge? That machine eventually lived and functioned perfectly for quite a few more years (ended up just needing a new HDD) until finally dying.

The dangers of aquadag charge are enormously exaggerated. The real danger is not that the shock will instantly vaporize you and everyone you love, but that when you disconnect the anode improperly the spark jumps to something-not-quite-ground and destroys electronics, or, when it jumps to you, you hurt yourself because you hit something or drop something.

Off-line SMPS are far more dangerous because their main caps actually contain 100-1000x more energy than a charged CRT tube. And unlike the aquadag on a tube these are very low impedance as well.

Re: 80386DX ISA single board microcomputer

#56

Post by pan69 » Fri, Nov 19, 2021, 10:06 AM UTC

guerrilla wrote: post #36

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!

> Props on going for a full 32MB of RAM.

He did do his own 4MB SIMMs, so...

https://alexandrugroza.ro/microelectronics/system-design/4mx...

Re: 80386DX ISA single board microcomputer

#57

Post by jonsen » Fri, Nov 19, 2021, 10:07 AM UTC

unixhero wrote: post #50

123pie123 wrote: post #47

These things remind me of one of my first jobs as a bench engineer 'trying' to fix PCs the vast majority of problems back then was the power supply and the vast majority of the issues with power supplies was burned out capacitors - easily fixable. for some bizaar reason one memory that also sticks out was the painful compatibility issues of putting seagate hard disks together with conner hard disks (IDE cables) also…

Good story! Everyone were correct about being afraid of opening CRT monitors. Repairing them is a whole other domain than PC electronics. A CRT ZAP from the cathode ray components can kill. That is not a place one should poke around trying to find solutions.

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.

Re: 80386DX ISA single board microcomputer

#58

Post by pan69 » Fri, Nov 19, 2021, 10:07 AM UTC

ane wrote: post #2

What a cool project. I really like the way he analyzed his failures, learned from them, and documented the process, and tried harder. I wonder, did he design the ISA bus by himself or did he use an existing one?

> I wonder, did he design the ISA bus by himself or did he use an existing one?

His own [1]. Many more projects by him [2]. Truly amazing.

[1] https://alexandrugroza.ro/microelectronics/system-design/isa...

[2] https://alexandrugroza.ro/microelectronics/index.html

Re: 80386DX ISA single board microcomputer

#59

Post by AshamedCaptain » Fri, Nov 19, 2021, 10:26 AM UTC

hmrr wrote: post #33

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 contrac…

I concur. This world is simpler than people think. They share specs on powerpoint files and the firmware is written (/built) by one guy during his breaks (I was going to say exactly this even before I read your comment)

Re: 80386DX ISA single board microcomputer

#60

Post by gadyke » Fri, Nov 19, 2021, 10:29 AM UTC

I've been watching this project like a hawk for months to see whether the final DMA/FDC bugs they identified get ironed out.

The idea of being able to hand-assemble a 386DX SBC, ISA backplane and Alexandru's other ISA cards is incredibly attractive to me - I find hand soldering to be entrancing in the same way some describe knitting.