16 Oct
2000
16 Oct
'00
3:20 p.m.
From: Ethan Dicks <ethan_dicks(a)yahoo.com>
Has anyone designed a quick-n-dirty Qbus IDE adapter?
If one is willing
to let the VAX processor do the work, it could be as simple as mapping
the I/O registers of the IDE drive into some I/O addresses. Not much
more than a few Qbus drivers and an address comparator, a la older ISA
IDE cards. It would probably heavily tax most CPUs, though.
Some Russin person did. it's out on the net somewhere.
As to taxing the older CPUs... How? IDE can do real slow, that's
not much of an issue. Most of the VAX cpus do not handle
interrupts very fast due to the huge overhead of context switch.
But they can PIO in a loop fairly fast, that is to the limits
of Qbus.
Allison
Allison