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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.