Autologout of unused terminals

Anton Rang rang at cpsin3.cps.msu.edu
Fri Dec 9 13:24:35 AEST 1988


Lots has been said on this, so just one fairly quick note.  It is
possible to compromise (gasp!) between these positions.  The
autologout program my undergrad school uses ("Bouncer"), locally
developed, includes the following:

  1.  It kills idle jobs after half an hour.  "Idle" is defined as
processes which aren't using CPU or doing I/O.  This is modified by a
set of configuration files and other things....

  2.  "Disconnected" jobs (terminal jobs not currently connected to a
physical terminal, for those of you who don't know VMS) are not killed
(since they aren't hooked up to a terminal, they aren't using enough
resources to be worth killing).

  3.  There is a list of users who are never killed (in a file).  This
isn't used much, but is available in the rare cases when needed.

  4.  There is a list of images (filenames) which shouldn't be killed
as long as any job in their "process tree" is running.  For instance,
a suspended editing process shouldn't be killed if its parent is doing
work.  (Again in a file.)

  5.  There is a list of terminals that users are never bounced from.
This is mainly for the system console.

  6.  This is the nice one (that makes reading all this worthwhile
:-).  Under VMS, each process has a list of "identifiers" (sort of
like groups under UNIX, but not exactly).  There is a "NOBOUNCE"
identifier which tells Bouncer not to kill the process, even if it
would otherwise be eligible for killing.
  Suitably privileged users can turn this on and off (not superusers,
just ordinary users who are allowed to do it--could be everyone).  So
if you're in your office and going out to lunch, locking the door
behind you, you could do a SET RIGHTS/ADD=NOBOUNCE (or something like
that) and know your process would still be there.  You could turn it
off later, if you wanted.

  So it *is* possible to compromise, with a little extra effort....

+---------------------------+------------------------+----------------------+
| Anton Rang (grad student) | "VMS Forever!"         | "Do worry...be SAD!" |
| Michigan State University | rang at cpswh.cps.msu.edu |                      |
+---------------------------+------------------------+----------------------+



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