17 May
2013
17 May
'13
6:49 p.m.
On Fri, May 17, 2013 at 8:38 PM, Rob Doyle <radioengr at gmail.com> wrote:
On 5/17/2013 12:01 PM, Cory Smelosky wrote:
IDE on a PDP-8 would be...interesting to say the least.
I played with an adapter about 10 years ago. I think it was a PLD with
some
buffers. I wasted the upper 4 bits in every word and took advantage of
the fact that the command registers are only in the lower 8 bits. PIO mode
transfers only, so it was really simple. It was impossible to get a handler
for OS/8 small enough to fit in two pages. I cheated and put stubs in the
lower fields and the handler itself in the high field.
The Spare Time Gizmos SBC6120 board has an IDE disk
drive. They've also
hacked a device driver for OS/8 that supports it.
And most of the device driver is in console memory space.
-chuck