Well, if it's going to be useful for older games, probably one of the most important things would be proper Sound Blaster compatibility, plus MT-32 and OPL3 and AWE support and all the other trimmings. And there would have to be VESA support, and probably variable speed throttling. Maybe even an extra means for plugging in ISA cards.

I suspect similar devices capable of running MS-DOS (but not being particularly useful for gaming) are already out there.

Keep in mind that this forum is for the emulation of PCs and hardware. You should ask in Marvin.

Sergey has made an XT processor board that plugs into an isa backplane, you could maybe adapt his design

http://www.malinov.com/Home/sergeys-projects

What I'd like is someone to build a range of brand-new 386 / 486 and Pentium boards.

Designs already exist, just takes obtaining a licence from a mainboard manufacturer. Produce in China and sell it for a fair price. People will be happy to pay a premium for a product like that.

Wikipedia's article "List of Single-Board Computers" turns up this set of x86-based items:

• fit-PC – AMD Geode LX 800 (fit-PC), Intel Atom Z5xx (fit-PC2), AMD G-Series APU (fit-PC3)
• MinnowBoard
• Intel Galileo
• PC Engines ALIX system boards – miniITX and smaller formfactor, models with and without VGA, AMD Geode LX800 CPU
• RoBoard based on DMP's Vortex86 processor
• Rockbochs 'Blackbochs' SBC – AMD Geode LX800 based, includes FXO/FXS telephony connectivity, multiple NICs
• Soekris system boards – without display connectivity, AMD Geode and Intel Atom CPU
• Winmate Communication Inc.

Any of these might provide a good starting point. At least, they may give some idea as to the relative complexity of using an x86 -compatible processor in a small form factor board. The Vortex86 SoC series (now PMX-1000) is particularly interesting - used in the Gecko Edubook and SurfBoard - but as I research each of these items further, it rapidly seems to be a project greater than my skill set : )

Industrial computers often use the CPU-on-ISA-card system with a passive ISA backplane. I think these are also still being produced at 486/Pentium speeds (Vortex86). But industrial gear is expensive and probably hard to obtain for private use.

quick example:
http://buy.advantech.eu/PCA-6108-0B2E/PCA-610 … A-6108-0B2E.htm
http://buy.advantech.eu/PCA-6194G2-D0A1E/PCA- … 194G2-D0A1E.htm
http://buy.advantech.eu/PCA-6781VE-M0A1E/PCA- … 781VE-M0A1E.htm

DonutKing wrote:

Sergey has made an XT processor board that plugs into an isa backplane, you could maybe adapt his design

http://www.malinov.com/Home/sergeys-projects

Can I turn an ISA motherboard into a passive backplane? AFAIK ISA slots are just extensions to the 8088/86 data bus, so I assume I would have to somehow disable the built-in CPU.

GL1zdA wrote:

DonutKing wrote:

Sergey has made an XT processor board that plugs into an isa backplane, you could maybe adapt his design

http://www.malinov.com/Home/sergeys-projects

Can I turn an ISA motherboard into a passive backplane? AFAIK ISA slots are just extensions to the 8088/86 data bus, so I assume I would have to somehow disable the built-in CPU.

What if you remove the bios so the board does not try to boot, and I suppose the cpu too. Does that make it passive I wonder.

Today I searched a little more to find out about SoC devices which incorporate an x86-compatible processor.

These appear to be the main (current) contenders in this space:

• AMD Geode GX / LX, or older AMD Elan
• DM&P Vortex86 and friends (PMX-1000)
• RDC?
• Intel Atom
• VIA (though I can't seem to find their chips anywhere)
• and other Chinese manufacturers / clones which I would have no idea how to source

...of which there are an abundance of little-known manufacturers of single-board computers based around these chips. Most range from $100-250 and come with VGA out, audio out, RAM, etc. A lot of it is, as you noted, designed for industrial markets: these boards get elaborate with 3x COM ports, a huge GPIO header, analog sampling inputs, etc.

This is just one example by EBOX which would be tough to beat as a hobbyist designer, as it seems to offer pretty much everything you'd need: VGA, sound, plenty of RAM, keyboard/mouse connections. http://www.compactpc.com.tw/product.aspx?act=detail&id=139

--

There are other solutions which don't involve using a "real" x86 processor, including doing the whole thing on FPGA (Zet project - http://zet.aluzina.org/forums) which could potentially then be implemented into the Replay board from fpgaarcade.com (http://www.fpgaarcade.com/).

Or if you really don't care about hardware accuracy, just run DosBOX on Raspberry Pi. http://www.youtube.com/watch?v=fvztpECEh_0

DonutKing wrote:

Sergey has made an XT processor board that plugs into an isa backplane, you could maybe adapt his design

http://www.malinov.com/Home/sergeys-projects

Wow, this man also made an Adlib clone and many other stuff. Everything looks like from a factory. The PCBs even have prints with his name. How did he do that?

I believe he orders them from a factory. I bought a PCB for his Adlib clone card and he told me he had placed an order for the PCBs and was waiting for them to arrive.

But yes his work is very impressive, he's basically designed and built his own complete XT machine with VGA and ide/floppy controllers and ATX compatible motherboard. 😀

DonutKing wrote:

Sergey has made an XT processor board that plugs into an isa backplane, you could maybe adapt his design
http://www.malinov.com/Home/sergeys-projects

Very impressive engineering -- if I was given this power, I'd like to build a 386DX craft with DDR3 memory 🤣

ratfink wrote:

GL1zdA wrote:

Can I turn an ISA motherboard into a passive backplane? AFAIK ISA slots are just extensions to the 8088/86 data bus, so I assume I would have to somehow disable the built-in CPU.

What if you remove the bios so the board does not try to boot, and I suppose the cpu too. Does that make it passive I wonder.

FYI, I've actually done a step-by-step test turning a damaged 486 mobo into a passive backplane. It worked finally but it was not a painless process -- I had to desolder all the active parts including chipset, bus transceivers and gates.

Looks like someone else is working on a tiny device using the Vortex86EX.

http://www.86duino.com/?p=68

No video-output on this device, but it's a start.

If you want to run dos and play games, go with a pentium 133, and use a PCI graphics card.

86Duino runs DOS old games: https://www.youtube.com/watch?v=UAyxTVKtKek#t=7m23s
http://www.86duino.com/index.php?p=95
http://shop.dmp.com.tw/INT/products/24
http://www.86duino.com/wp-content/uploads/201 … V14_86duino.pdf
https://www.youtube.com/watch?v=FUpe5dz0qw4

Compared to Intel's, 300 vs 400 MHz, 128 vs 256 MB, but it has a built in ISA BUS interface and is $20 less, bare dev boards even less, and less power usage than intel's, which is rated for 15w max, 7w by by calculations of someone comment about what it will run off of(there's 1.6ghz atoms that run at these power figures, so much for the new intel chip being 1/10 the atoms power draw,) vs 3w max, 2w usual for the 86duino.

ih8registrations wrote:

but it has a built in ISA BUS interface and is $20 less

So you can actually plug a full-size ISA card into it somehow?

A quick Googling finds a bunch of references to ISA, but it appears the term is used to refer to "instruction set architecture" and not "industry standard architecture".

As the CPU PDF I linked to shows, it has "X-ISA bus interface," ISA with some pins removed. It also has p5 ISA, but there is a lot of misinformation spread about this chip from people saying without checking, some people saying not ISA bus, others claiming no FPU(wrong and wrong.) I just noticed something interesting, while what's currently being offered are running at 300MHz, the PDF shows designed for 400 MHz, so they're underclocking.

For me it's all about getting ISA sound cards to work. Had Wing Commander running on my Atom netbook. Boot from USB, throttle disabled cache and off it went 😀

But the missing sound is the big problem.

I still think that all we need is a "replacement" vintage motherboard.