PDP-8/S #1

Digital Equipment PDP-8/S, S/N 517

PDP-8/S rescue and restoration blog.

Software that came with the PDP-8/S.

The PDP-8/S was introduced in 1966 as a low cost version of the PDP-8. The "S" is said to stand for Small, but most say it stands for Slow. It was about 10% of the performance of the PDP-8 and about 20% of the cost. The $10,000 price included 4K of core memory that was expandable to 32K. The successor PDP-8 models that were introduced in the early 70s were much faster than the PDP-8/S and also supported DECtape magnetic tape drives. Most of the (1000 or 1500 depending on the source) PDP-8/S systems were scrapped. There is one at the Computer History Museum, one at the Living Computer Museum, one at the Goodwill Computer Museum, and just a few in private collector's hands.

This DEC PDP-8/S was donated to the RICM by a Robin Katz Banks. It was originally used to analyze heart regional and global wall motion data from a very high speed X-ray system at Temple University in Philadelphia, PA.

This system has 4K of core memory. There were no disks or tapes on this system, all information was read and saved on paper tape.

The PDP-8/S was introduced on 23-AUG-1966. It was designed by Saul P. Dinman and was the first CPU to cost less than $10,000. It is constructed entirely from standard DEC flip-chips and does not contain any integrated circuits. Just the processor contains 1001 transistors. The internal architecture of the CPU is serial making it much slower than other PDP-8 systems. The CPU instruction set is also a little different, so it will not run the same software as other PDP-8 systems.