[2][3] DECUS was legally a part of Digital Equipment Corporation and subsidized by the company; however, it was run by unpaid volunteers.

It was organized by processor and operating system, using information submitted by program submitters, who signed releases allowing this and asserting their right to do so.

There were two DECUS US symposia per year, at which members and DEC employees gave presentations, and could visit an exhibit hall containing many new computer models and peripherals among other things.

This activity grew with time, and in the spring of 1977 some volunteers from the RSX SIG (Special Interest Group) led by Phil Cannon, Jim Neeland, and several others, arranged an informal drop-off, and made master distributions of all material submitted.

By fall 1979, there was a release form used with submissions, so that the DECUS library could redistribute the combined tapes, making them more easily available to members who did not get to the symposia.

In these cases, the person desiring the material was expected to furnish blank media, as no money ever changed hands.

The SIG tapes contained a large variety of material which has been useful as examples of prior art in patent disputes.

They always favored distribution of full sources (and occasionally did omitted binary-only submissions), making them match what patent examiners understand as "publication".

The pioneering titles Adventure by Will Crowther; Baseball, Dungeon and Star Trek by Don Daglow, and Hunt the Wumpus by Gregory Yob provided a foundation for the games industry.

Association activities: The HP User Society DECUS promoted the exchange of information and know-how between its members, manufacturers and partners.

The association supported its members in the representation of their interests against HP and partners, helped in problem solving and facilitates formation of opinion and advanced training by organizing events.