TOPS-20

TOPS-20
Type:	Multi-tasking, multi-user, virtual memory
Creator:	DEC
Architecture:	PDP-10
Date Released:	1976

TOPS-20 is an operating system for the PDP-10, DECSYSTEM-20. It was descended from TENEX, an operating system for a modified version of the earlier KA10 PDP-10; hence its nickname of TWENEX.

Networking

TOPS-20 can work with DECnet and with TCP/IP. It was a popular machine on the Internet during its early days (1980s).

MIT added support for CHAOSnet.

How to get this running

TOPS-20 can run under emulation in SIMH, KLH10, and kx10.

• Running TOPS-20 V4.1 under SIMH
• Running TOPS-20 V3A and V7.1 under SIMH

External links

• TECO, TENEX, and TOPS-20 Papers - from Dan Murphy, includes assorted memorabilia such as images
  • Origins and Development of TOPS-20
• Phil Budne's TOPS-20 Evolution