modified on 1 October 2015 at 01:54

DEC PDP-11/70


Jump to: navigation, search

This is one of my most prized possessions, a near-pristine DEC PDP-11/70. This one is of the somewhat unusual DECdatasystem-570 configuration, which is built into shorter-but-wider racks and painted in a blue color scheme as compared to the usual purple. The DECdatasystem machines were usually marketed to business customers as opposed to scientific applications.

It was in service for nearly twenty years at a printing company in Pennsylvania. It, along with its two sister machines, ran all job scheduling for the printing presses, as well as ran all of the "business" stuff like accounting, payroll, and customer database management. I, along with my friends Brian and Sridhar, adopted all three of the machines. Brian and I rented a truck and picked them up in the fall of 2002.

This system works as well today as it did when it was built in 1974. It runs the RT-11 and RSTS/E operating systems. I fire it up every so often for fun, for data recovery jobs, or to demonstrate to guests.


  • KB11-C processor
  • FP11-C floating point unit
  • 1MB of RAM (a lot for 1975!)
  • UDA50 disk controller
  • One RA90 disk drive
  • TE16 9-track magtape drive
  • DELUA Ethernet controller