5 Feb
2008
5 Feb
'08
6:44 p.m.
On Tue, Feb 05, 2008 at 01:43:19PM -0800, John A. Dundas III wrote:
As did every one I ever saw.
At 3:52 PM -0500 2/5/08, Patrick Finnegan wrote:
>On Tuesday 05 February 2008, der Mouse wrote:
>> > ever heard of the Vax 11/750 ? You know, the one with the PDP-8 FEP
>> > ?
Indeed - ???
>> Sure you don't mean the 780? I
didn't think the 750 had a FEP at
>> all; at least, on the ones I used I didn't see anything identifiably
>> FEPish, either hardware or software. (I also *think* the 750 wasn't
>> around pre-1980, but I'm a lot less sure of that.)
I completely agree. I managed two 11/750s between 1985 and 1994, and I still
have one of those two (S/N BT00000354). There is nothing FEPish, but
there is something like an ODT console program. You can examine registers
with it, but I only ever did that once (debugging a problem with a
second Unibus interface - L0010, IIRC). Mostly, folks just install
a boot ROM to match the boot device and twist the A-D selector
switch to the correct position and press "reset". We had three ROMs
in ours - the default console TU58 boot (position "D"), MSCP ("A" in
our
case), and a "DR" boot ROM for either an RM03 (or RM05) on the MASSBUS or
for our SI9900 w/SMD disk that I talk about here from time to time
(emulated dual RM03 plus an oversized RM05).
The 11/730 (and 11/725) has an on-board FEP - an 8085. You talk to
it much in the same way as you do to the LSI-11 in an 11/780, except
its console medium is TU58 tape, not RX01 disk. Syntactically, though,
I believe it's similar (I know the KA730 well, but not the KA780).
The VAX-11/750
currently in my basement certainly doesn't have a PDP-8
installed in it. Pictures:
http://computer-refuge.org/compcollect/dec/vax/11750/index.html
An 11/780 does have a PDP-11/03 in it as a console subsystem (it's
really really not a front-end processor, no sane person would let a
user bang away at the console of an 11/780
I'm with Pat on this. I managed a lot of /780s; they all had LSI-11s
as the front end. Also, never saw a /750 with a PDP-8 front end.
Managed a few of
these too, though this timeframe is a bit hazy. According to Gordon
Bell
<http://research.microsoft.com/Users/gbell/Digital/timeline/32-bit.htm>
the /750 was introduced in late 1980.
Perhaps someone is confusing the 11/750 with some model of PDP-10? I
know that there was a PDP-8/i-based I/O subsystem for one of the -10s.
I've also seen an -8/a in the block diagram for a peripheral for some later
model of -10 (does a "DX10" ring a bell to anyone?) Most of the -10s I've
seen personally, have an -11 for an FEP, but I am not an exhaustive
authority on 36-bit hardware, especially not, say, a KA-10. I've stood
in front of a few KS-10s and perhaps a KL-10.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 6-Feb-2008 at 02:30 Z
South Pole Station
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Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html