DEC PDP-11/70 (“Miss Piggy”)

Minicomputers   |  Introduced in 1975   |  Digital Equipment Corporation (DEC)    « Back to Computer List
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The PDP-11, introduced in 1970, was one of the most popular and long-lived of DEC’s product lines, the last model being introduced in 1990.

The PDP-11 was DEC’s first 16-bit system and was introduced to compete with rival Data General (an upstart computer rival formed by a small group of DEC engineers who grew frustrated by DEC’s hesitancy to embrace 16-bit designs). DEC engineers designed the PDP-11’s input/output with a system called a Unibus, which resulted in a highly flexible system capable of handling a number of custom peripherals. Moreover, DEC published the specifications, which allowed customers to design their own custom peripherals. Its features established the PDP-11 as DEC’s flagship computer for science, engineering and industry. The system’s time-sharing capabilities made it an important system for the spread of ARPANET: by March 1977, PDP-11’s accounted for over 30% of the nodes on the network. Throughout the 1970s, DEC sold more than 170,000 PDP-11 systems. In all, some 600,000 were produced.

LCM+L’s PDP-11/70, nicknamed “Miss Piggy,” was used at Microsoft by the team that developed Word and the spreadsheet application Multiplan. It ran Microsoft’s own variant of Unix (Version 7) called Xenix. Miss Piggy was retired from Microsoft in 1986, and is one of several systems available for remote online access.
Usable System
Online Access
DEC PDP-11/70 (“Miss Piggy”)


  • 16-bit word size, magnetic core (later semiconductor) memory, capacity of 32K to 2M words
  • 980 nanosecond instruction cycle, 2.5 MIPS