20 Jun
2009
20 Jun
'09
12:33 p.m.
From what I've been able to tell, these boards
can be used for
diagnosing things at the microcode level on (at least) the first
generation microcoded Unibus PDP 11's (11/35, 11/45, 11/05) as well as
diagnosis of the RK11 disk controllers (with an appropriate plastic overlay for the indicator lights). The question I
have is can this be
used on an 11/34a to step through the microcode?
AFAIK it can't be used on an 11/34. There is a way of single-stepping the
microocde on an 11/34 -- IIRC you link a couple of special cables between
the frontpanel control board and one of the CPU boards (10 wire ribbon
cables?) There's then some odd key combination on the panel that lets
you single-step the mircocode.
The 11/34a runs fine so I don't need them for
actual diagnostic work,
but it'd be at least cool to try out the KM11s (I understand that two
are needed) and watch the lights if they in fact will work on the
Not all devices need 2 KM11s. The 11/45 can use two, but one is for the
main CPU, the other for the FPU. You cna use one at a time. The RK11-C
really needs two, the RK11-D and RX01 just have one KM11 connector. I
can't remember the 11/40.
-tony