Getting Into TWENEX

This tutorial aims to bridge the gap between introductory documents like “TWENEX Starter Guide” and “TOPS-20 Interactive Tutorial”, and mastry of the TWENEX user environment.

The initial version will consist of a list of reference documents and a listing of's file system contents accessible by user papa as of 24 May 2010. Contents will be Refined, improved, and expanded as the author explores the system.


TWENEX and similar operating systems running on DEC PDP-series computers during the 1960s and '70s were the incubator for Unix, the Internet, the free software movement, networked collaboration and socialization, and most of what some refer to as hacker culture.

I used some of these systems, though I don't remember which, on a couple of occassions between junior high and college before I understood their significance or what computing would come to mean to me personally. Once I got into Unix-like systems, I wanted to understand the systems out of which Unix had developed, to see why things are as they are in Unix, what aspects of the older systems were carried-over and what aspects were rejected.

TWENEX represents the path not taken, or Unix as it might have been.

Reference Documents

SMJ. ”TWENEX Starter Guide for UNIX Users”. SDF Public Access TWENEX. 19 July 2001. <> accessed 24 May 2010.

TOPS-20 Interactive Tutorial”. SDF Public Access UNIX System. 23 May 2010. <> accessed 24 May 2010.

TOPS-20 User's Guide”. SDF Public Access TWENEX. June 1988. Digital Equipment Corporation. <> accessed 24 May 2010.

TOPS-20 Commands Reference Manual”. Jean-Marc Bourguet's PDP-10 Page. July 1990. Digital Equipment Corporation. <> accessed 24 May 2010.

Does not apply to SDF-EU.

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