scd and mcd

perryh at perryh at
Sat Apr 23 23:25:10 UTC 2011

Warner Losh <imp at> wrote:

> mcd and scd are ISA-only devices ... They were important for the
> 386 (now not supported) and 486 machines.  Since the 486 machines
> in question maxed out at 32MB, and 8.x has trouble running in 32MB
> on x86, I'm guessing there aren't too many 486 SX/DX machines
> running 8.x.

486 were the last for which ISA was the primary bus, but ISA was
still present (bridged from PCI) on most Pentium systems and common
at least as recently as Pentium-II.  (I don't have a disassembled
P-III handy to check whether it has an ISA slot.)

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