27 Jul
2010
27 Jul
'10
2:20 p.m.
On 7/27/10, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Goin back ot the very early Unibus devices, there were
3 cards -- the
device controlelr itself, an M105 address selector (which had jumpers to
set the device address) and an M782/M7820/M7821 Interrupt card which had
the jumpers to set the vector.
Good point. I had forgotten about those - all of my comments apply to
SPCs (Small Peripheral Controllers), not backplane-sized devices
(there were a few SPCs even in the earliest days, like the LP11 I
mentioned).
I have never configured a system with the multi-card/system-unit form
factor, but the bus interaction is all the same - the only difference
is that I think all the options are set with those older card with
"straps" (soldered in jumper wires) vs DIP switches or driver-supplied
parameters.
-ethan