Mutant01 IP = 205.138.39.180 - test-drb@ccmp.vtda.org

15 Mar 2000

On Mar 15, 18:35, Tony Duell wrote:
...
  > Anyone here have any vintage software to run on a
PDP-11 as a front end
 > connection server? 
Nope, I don't have the software, but one of my 11/23's was originally a TCP
(see below) at Edinburgh University.

...
  > Waterloo University used a PDP-11/45 back in the
'70s in
 > front of their *huge* cluster of some 3-500 DEC minicomputers. I've got
 > heaps of DZ,DL,etc..  from the warehouse so serial ports are not a problem.
...

 Cambridge Universtiy (UK) did something similar as a frontend to their
 IBM 3084 mainframe.

 As I understand it, the system consisted of units called JNT-PADs (which
 were basically Async -> X25 PADs) which took incoming connections from
 terminals and then sent them (as X25 packets) to DUP11s. There were other
 DUP11s handling external connections to/from JANET (UK academic network).
 Some local terminal connections came in on DJ11 lines. These were on the
 Unibus of a number of PDP11s (11/45s, later 11/34s) which communicated via
...
  DMC11s and DMR11s. There were a couple of DX11s that
linked the PDP's to
 an IBM channel. 
Edinburgh Regional Computing Centre (part of Edinburgh University) used to
do something similar.  According to the chart I still have (dated 1985),
ERCC had eleven 11/10s, eight 11/23s, three 11/40s, and a few 11/34s and
11/03s connected as Terminal Control Processors (TCPs, basically front end
processors for fixed or dialup terminal lines).  I'm not sure what the
interfaces were, but my 11/23 had a pair of DLV11-Js when I got it, and
originally a synchronous line as well (which I think went to a GEC packet
switch).  ERCC also had an 11/34 and an 11/40 connected to the central
processors to handle "slow devices", and fourteen CAMTEC PADs, as well as
several VAXen, other PDP-11s running RSX, a few Systimes, a few Pr1mes, a
couple of DEC 10s, an Amdahl 470, a few big ICL 2900 mainframes, a few
GECs, and at least one Data General machine.

Altogether, Ednet supported 33 local host systems, 100 synchronous and 1521
async connections.

Leeds University also did something similar, up to about 1992.  They had
three 11/34s with (AFAIR) 32 serial lines each (mostly Emulex devices)
feeding a pair of DX11s into a big Amdahl.  The 11/34s ran some homegrown
software, booted from an RX02.  There was also a couple of 11/73s, one of
which was in a proprietary unit that incorporated a DX11-alike on two (or
maybe three) Q-bus boards.  That one also had some wierd CAMTEC ethernet
interface in it.  I've got one of the 11/34s, and one of the 11/73s; one of
my friends has one of the DX11s.

-- 

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York