Thread

Ask HN: Who's still keeping a DOS machine up because the business depends on it?

297 points · 304 comments · mlaux

andix · 1790376456 · focus · HN ↗
Just out of curiosity: is it possible to somehow attach an ISA Adapter via USB to a VM? ISA does depend a lot on DMA and timing, but the clock is only 8 mhz and gives a software layer on a modern cpu a lot of time to do stuff between ISA bus cycles.
Keeping old hardware running is very fragile. Most spare parts are decades old now too, and nobody knows if they still work properly.
1. lysace · 1790377765 · focus · HN ↗
  USB and VM latencies are both questionable here, I would think.
  ISA motherboards still work and have been mass produced in the hundreds of millions. (I have about a dozen in my retro closet.)
  The esoteric ISA expansion cards would be the bottleneck, not the motherboards.
  1. andix · 1790378221 · focus · HN ↗
    All those layers add some latency, but 8 mhz is really slow. USB 4 can do extremely low latency, otherwise PCIe over USB wouldn't work.
    lysace · 1790378665 · focus · HN ↗
    This looks quite interesting:
    <a href="https://www.reddit.com/r/vintagecomputing/comments/jbaw38/isaoverusb_using_real_isa_cards_in_an_emulator/" rel="nofollow">https://www.reddit.com/r/vintagecomputing/comments/jbaw38/is... (2020)
    ISA-over-USB, using real ISA cards in an emulator
    <a href="https://github.com/Manawyrm/ISASTM/" rel="nofollow">https://github.com/Manawyrm/ISASTM/

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