3 ms·
As the owner of an obscure floppy disk subsystem that requires an 8-bit ISA card and was originally spec'ed to run on XT-class hardware, this is tempting. In p
by jasomill 3y ago
As the owner of an obscure floppy disk subsystem that requires an 8-bit ISA card and was originally spec'ed to run on XT-class hardware, this is tempting.
In particular, 640 kB really is enough, as the bundled software runs in real mode, doesn't support extended or expanded memory, and predates tricks like loading DOS in high memory by a number of years (not that they'd work on an XT in any case).
The disk read/write code and some of the simpler filesystem modules run on the ISA card itself, essentially an 8085-based SBC with a rather flexible (no pun intended) floppy controller. Here, 64 kB is necessarily enough for everything.
The fun part is that, assuming an Intel MDS 80/ISIS-compatible toolchain, the card can easily be coerced to run arbitrary code. And, while working Intel "blue" hardware is thin on the ground, I have personal experience with at least one working emulator (MAME) able to run ISIS.