DEC PDP-11/40 Minicomputer

The PDP-11 architecture, introduced in 1970, was designed to cover a wide range of price/functionality ratios. The PDP-11/40 (1973) is the direct descendant (in the equal-cost/increasing-functionality line) of the PDP-11/20, the root of the PDP-11 family tree. Our machine has 8k 16-bit words of core memory and is equipped with a fast papertape reader/punch, an RK-05 cartridge disk unit, a double DECtape unit and a pair of RX-11 8" single-sided floppy drives. The presently used console is a DECwriter II matrix printer, replacing the original Teletype 38 ASR unit shown in the picture. This machine has been used for a long time (1973-1990) as a local data concentrator for the Cyber mainframe computer at the University Computing Centre (SARA). Running the RT-11 operating system, this PDP-11/40 is still in use in our museum as a host for various peripherals among which a Documation punched card reader. The picture shows the PDP-11/40 in its original state. There is also a close-up of the console and papertape reader/puncher.