it's funny, i was wondering how i could use my old 386 cpu that i saved from my first computer. the memories of running slackware 1.0 on it is still vivid. ah that moment i got my first X server running :)
80386DX ISA single board microcomputer
61–70 of 139 posts
Re: 80386DX ISA single board microcomputer
#62It would be so awesome if this guy may start producing and selling these in small quantities.
Re: 80386DX ISA single board microcomputer
#63Earlier quoted context omitted.
Somewhat. The internal speaker in the original PC was pretty much just a buzzer that was probably never intended to output anything else other than simple status beeps in office settings. It does not even have the ability to modulate its amplitude, i.e. its voltage level is either "full on" or "full off" and tones are usually played by doing that, for example, 2000 times a second to get a 2kHz square wave tone. There…
This. PC speaker was driven far beyond its original design and intention. Sound Blasters, and later built-in clones/compatibles, changed the general outlook of sound. You'll see a shift to Adlib/SB audio start around 1987-1988, and by 1991 they were no longer niche. PC speaker support started to wane, but didn't entirely go away until Windows 95. How do I remember this? I ran a BBS in the 90s, and my family was one o…
I remember an old demo that would play a loop of the chorus of I Say a Little Prayer through the PC speaker. It was hard to believe that the speaker could be pushed to such limits.
Re: 80386DX ISA single board microcomputer
#64I 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 ?
I'd be surprised if the various compilers coudn't; especially Watcom.
Re: 80386DX ISA single board microcomputer
#65[deleted]
Re: 80386DX ISA single board microcomputer
#66How long until it receives a Pentium?
Re: 80386DX ISA single board microcomputer
#67Although 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 requirement of 486 CPU, was able to run on the 386DX40s, albeit a bit slower than intended.
Since we had two PCs we wanted to play together, but only had a parallel cable. I don't know why it was so hard for us to get hold of a serial cable, but the point is we only had the parallel one and Warcraft II would only be able to run over serial cables, not parallel ones.
I eventually worked out a way though. The 386DX40s were actually also capable of running Windows 95 which had a feature where you could "network" two PCs over a parallel cable. I then ran IPX/SPX over that network which allowed us to play Warcraft II over it.
The gameplay was pretty slow, but as I recall it was very reliable and we played quite a bit on this setup. Eventually we got a couple of BNC network cards and cables for a much more conventional setup.
Re: 80386DX ISA single board microcomputer
#68It 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.
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...
Those do exist, e.g. the Vortex86 SoC[1] comes to mind.
Not sure if the AMD Geode GX/LX series[2] counts, since they IIRC have an external support chip. Some years back I used to work with router boards and industrial PCs that used them. I still have an industrial PC sitting on a shelf with an Eurocard[3] sized SBC and the ISA bus connected to a DIN41612[4] back plane.
The Geode implement a large subset of the i586 ISA tough (the LX also have an AES extension), but some other instructions are missing. I'm also not sure if they still make them any more, but given how many industrial products they're in, I'd bet there are warehouses full of them somewhere, until the last support contract expires.
[1] https://en.wikipedia.org/wiki/Vortex86
[2] https://en.wikipedia.org/wiki/AMD_Geode#Geode_LX
[3] https://en.wikipedia.org/wiki/Eurocard_(printed_circuit_boar...
[4] https://de.wikipedia.org/wiki/Datei:DIN41612-c-federleiste-c...
Re: 80386DX ISA single board microcomputer
#69Earlier 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.
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!
Re: 80386DX ISA single board microcomputer
#70Earlier quoted context omitted.
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 a…
You need to discount here for CRT size. A 9" will zap you, a big 30" Barco will happily kill you if you are not going to be careful, those things will put out HV at appreciable current. Ditto for old glass tube large screen color TVs.