Idle time logout mechanism (daemon)

[Doug Gwyn <gwyn>]

There is NO reliable way for the system to tell whether a user has
wandered forgetfully away from his logged-in terminal or if he is
in fact still using his connection.  For example, at BRL we have
quite a few Teletype 5620 DMDs (these are really nifty), and it is
not at all out of the question for all interaction to be happening
entirely within the DMD terminal itself for many minutes on end;
yet the connection to the host must remain open for when it's needed.

Our solution is to enable a TIMEOUT feature in the shell, and to
set TIMEOUT=0 (disabled) in /etc/profile (or equivalent) when the
user is found to be logging in on a 5620.  This scheme protects
against forgetful naive users without getting in the way of
DMDs or knowledgeable users.