"tenex", where does the word come from?

[Philip Budne]

TENEX stands for TEN EXecutive, an operating system developed for the
PDP-10 in the early 1970's at BBN.  A major goal was the production of
a user friendly, user mode command interpreter (the EXEC) that had
command completion and "incremental help"; at any time, in any command
a user could type <ESC> to "complete" the keyword or filename being
typed, or type "?" and see an explanation of valid options at this
point in the command parse. The "Load Average" in BSD is a legacy of
TENEX.

TENEX (and TOPS-20 "Twenex"), share with Un*x the idea of a user mode
command interpreter with user programs executing in 'forks'.  Another
similar point was the design decision that "no operating system
maintained structures should exist in the user's adress space".

However the T(w)ENEX monitor performs many operations in the supervior
such as username translation and 'globbing' performed by libraries or
the shell in Un*x. TENEX also has a rich set of terminal, virtual
memory, and fork management primatives.  An interesting abstraction is
the equivalence of disk and memory pages; useful for databases and
shared libraries.

Ken Thompson acknowledged in his Turing award speech that if Dennis
Bobrow's AI group had been poorer and had had to settle for a PDP-11,
that Bobrow might be standing there instead of him.