Remote job submission from PDP-11

Chris Zach cz at
Wed Oct 7 13:00:43 CDT 2020

Interesting. I think these came from that E-COM US Postal Service thing 
in the late 1980's where the USPS built a pilot system to allow you to 
go into a post office, give them a letter, then they would scan the 
letter, route it through a network of pdp11's to the destination PO 
where it was then printed out and delivered. Yes, I think this was when 
a Fax machine was a very very big thing.

Interesting part is they used these boards for interconnections. The 
actual node was a pdp11/23 CPU with 256kb of memory, one or more of 
these things (which if I recall could handle 8 serial lines each), a 
multifunction board with clock, parallel interface (for printer), serial 
ports, and of course a pair of RM02 disk drives.

Before you consider that to be an impossible system, each system had a 
special Plessy bus in a BA11 type chassis that had a voltage regulator 
to make the +12, a Q bus/Unibus backplane that had a Plessy Quineverter 
to talk to the Unibus stuff. Even the RM02 so the Quniverter did have 
DMA capability but I don't recall if it has a unibus map (I have one or 
two of those here somewhere as well. I have a lot of stuff)

This is how Doug and I met at Alan Frisbee's place in Greenbelt to split 
a horde of RM02 disk drives and other stuff. Man this is going back 
years, but I think I still have a lot of the documentation for this 
project somewhere in the paper piles, it was a weird concept.

On 10/7/2020 12:36 PM, Al Kossow via cctalk wrote:
> On 10/7/20 8:29 AM, Chris Zach via cctalk wrote:
>> That sounds like it, and I might have been the one to upload the 
>> drivers. Let me find one in the shed and take a picture.
> from Larry Baker
> they were popular X.25 cards that had BSD support
> I think that's what we used at Apple to get on NSFnet

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