Introduction to the Greenough PDP 11/20 collection
In August 2007, MARCH acquired a PDP-11 system. When I came to InfoAge to help Evan set up the new exhibit and storage rooms, I saw that it was an 11/20, with a largely complete collection of manuals, schematics, and even the paper-tape operating system. I saw right away that this could be the basis for an exhibit of the "state of the art" for 1970's DEC minicomputers, even without running the system. Evan agreed (after some consideration) and, with encouragements from other MARCH members, I'm working the details.
In addition, MARCH soon found that this system was part of document scanning systems developed by the US Government's National Bureau of Standards (NBS, now NIST) from the 1950's through the 1990's. This particular system was donated by M Leighton Greenough, who developed systems used those systems at NBS and later as a consultant. He eventually purchased it and continued to do similar scanning work for the US government. Mr. Greenough was kind enough to write a description of his history with the system and provide photos which are now available. This particular PDP-11/20 was used for evaluation of experimental scanning techniques and not for production scanning.
This 11/20 donation includes the original 1969 distribution of DEC's paper tape operating and development system, including paper tapes and manuals. A description of the DEC paper tape software system and its console of switches and lights, is on the Web pages linked in this section.