20 Nov
2003
20 Nov
'03
8:39 a.m.
On Thu, 2003-11-20 at 12:37, Geoff Reed wrote:
>(Logically-speaking, the 8086 was an accessory to
the Z80, whivch owned
>all the peripherals.)
I always found the Rainbow architecture kinda cool
actually, when running
in x86 mode the Z-80 functioned as a dedicated IO processor, freeing the
X86 to run your programs without having to deal directly with the preipherals.
If I recall, performance wise they werent' bad! They had shared
*memory*, not all that much of it and weird semaphores I think, but it
suuure beats a shared IO port or other nasty hack. Actual overlapping
IO.
It wasn't possible with MSDOS, but you could easily queue up disk
writes/reads on hte Z80 side, and have the Z80 tell the 8086 only upon
error, etc.