DEC PDP-11/70

This PDP 11/70 was donated to the RICM by Steve Hort of Mount Vernon, NH. The 11/70 is arguably the largest PDP built by Digital Equipment Corporation. This drive on the right is one of two RM03 Massbus disk drives. The right cabinet has the CPU in the bottom and spare parts in the top. The center cabinet has a TU16 tape drive in the top and the tape formatter in the bottom. The left cabinet has a RX02 floppy drive in the top, an RL02 disk in the middle, and two MJ11 core memory chassis in the bottom. It now has 768KB of core memory and has room to expand to 1MB of core memory. The system appears to be complete but will need a little TLC before it will run.

The system has four chassis that contain boards. The chassis on the right contains the processor, Massbus controllers, and a small section of Unibus. It does not have the optional floating point processor. The chassis in the middle contains Unibus I/O boards. The two chassis on the left contain the 12 sections of 32K x 19 bits of core memory.

There are two Core Memory Chassis in this system.