z386: An Open-Source 80386 Built Around Original Microcode

(nand2mario.github.io)

34 points | by wicket 1 hour ago

3 comments

  • KellyCriterion 2 minutes ago
    Question: Are there today any 386 instances running somewhere in the basement to do some productive stuff, maybe processing only some controller data once a day?

    I remember the link some month ago where that one small shop ran completely on an old Amiga (?IIRC, not sure, was linked here)

    Around 98/99 I was involved in a small IT-management company serving SME around the region, we had a client producing distinct metal objects with a big press; this got feeded once a day with a 5.25 floppy from another machine with production data - and it was still in use while we had already ethernet/USB/3.5 floppies etc. :-D

  • cbdevidal 13 minutes ago
    Of course they tested Doom :-D

    They might also run Linux kernel 3.7, that supported i386. Gray386linux is still maintained, and runs a patched 3.7 kernel.

    https://github.com/marmolak/gray386linux

    • KellyCriterion 5 minutes ago
      haha, this was my first thought when I read the headline, because this "classic test" always comes up here :-))
  • mmastrac 58 minutes ago
    Did the microcode disassembly find any useful backdoors to read microcode without decapping?
    • nand2mario 51 minutes ago
      Not really. The 386 does not have an interface to read the ROM direclty. Instead, it uses the Built-In Self-Test (BIST) to verify the ROM's contents. It's basically a checksum-like mechanism that verify the integrity of the CROM.