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From: Merle K. Peirce <at258_at_osfn.org>
Date: Tue Sep 14 22:09:16 1999

Our latest acquisition is a PDP-9, one of 455 built. It served until
this summer controlling a very large 60"x60" XY plotter. This is one of
only 2 of this size in the world, and is used to prepare glass plates for
etching. The plotter moves in increments of 1/10000 of an inch. The
plotter was built in the late 1960's by Concord Electronics in
California. The plotter is built on a granite slab about 3 feet thick,
which rests on supports which were drilled down to bedrock. In order to
be installed, the rear wall of the building was removed. The Concord
controls fill 3 cabinets, and these are controlled in turn by the PDP-9.
Two PDP-11's are used to control and programme the PDP-9. This summer a
more modern control system the size of a filing cabinet replaced the 3
six-foot control racks, and a Dell server and UPS replaced the DEC's. We
were give the PDP-9, PDP-11's, and Concord control parts, as well as
spare flip chips, terminals, paper tapes, manuals, etc.
Received on Tue Sep 14 1999 - 22:09:16 BST