[TUHS] PDP-11 questions

Pete Turnbull pete at dunnington.plus.com
Tue Jan 26 02:18:06 AEST 2016

On 25/01/2016 11:29, Tony Finch wrote:
> Norman Wilson <norman at oclsc.org> wrote:
>> It worked both ways, of course.  I too suspect that a
>> majority (though I'm not so sure about `vast') of PDP-11s
>> never ran UNIX.
> A random vaguely off-topic example: in Cambridge a PDP-11 was used as a
> terminal multiplexor for the IBM mainframe.

The University of Leeds did something similar - an 11/34 with a lot of 
Emulex serial lines and an RX02 to boot from, was connected to their 
Amdahl. I remember the RX02 particularly because when we decommissioned 
it and took out the floppies, both had completely transparent rings on 
or near track zero, so it obviously had been left running and not 
rebooted in quite some time.  In the same machine room there were two 
third-party cabinets with KDJ11A CPUs, more serial lines and IBM channel 
interfaces. They also had at least one DX11.

The University of Edinburgh used several small PDP-11/23s in BA11-N 
boxes as terminal/network concentrators for EMAS. I can't remember how 
they worked but I remember they had one sync serial interface and a 
bunch of DLV11-Js.


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