7 Oct
2015
7 Oct
'15
2:52 p.m.
It should be easy enough to install on a test system, check the address
space where typical bootstraps go, see what's there, etc. Thanks.
On Wed, Oct 7, 2015 at 4:58 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
On 2015-Oct-06, at 9:18 AM, Henk Gooijen wrote:
--
Bill
vintagecomputer.net
-----Oorspronkelijk bericht----- From: william
degnan
Sent: Tuesday, October 06, 2015 2:26 PM
To: cctech
Subject: DEC pdp 11 "R-K ABBR. BOOT P. C. Board"
What is the purpose of this controller? It came with a PDP 11/05 system:
http://vintagecomputer.net/digital/PDP11-05/dec_r-k_abbr_bootPC_Board-a_fro…
Printed on the controller is
R-K ABBR. BOOT P. C. Board 609395 Rev B
802000 Rev
I searched around, found nothing specific Is this a bootstrap board for
an
RK drive?
--
Bill
vintagecomputer.net
=========
I am clueless too, but if you want to play Sherlock Holmes,
it should be possible to figure it out.
20 ICs, several will be familiar in use in circuitr for the bus.
I'd first check whether it is intended for UNIBUS (likely) or QBUS.
Given the IC types you can estimate the circuit complexity.
If there are lots of simple gates it is just a puzzle.
The board has good quality machined pins, so after making pictures
and a drawing the location of each IC, you could pull them and
trace every pin, visually and with an Ohm meter. Lots of work, not
difficult, but very time consuming ...
Good for the dark evenings :-)
IC date codes are 75/6, I guess that's just late enough to be QBUS, but
more likely UNIBUS.
Can't discern all the IC types but some speculation based on what can be
seen: the labeled IC could be a 256*4 PROM, when a memory read-cycle is
initiated the 74221 monostables sequence the reading of 4-bit chunks into
the the 74175 latches to make up a 16-bit word for presentation on the bus.
The jumpers at centre-bottom could be the base address.
A 256*4 PROM would give a 64-word bootstrap.
Easy board to reverse-engineer.