Yet another idle daemon

Stephen Crawley scc%computer-lab.cambridge.ac.uk at ucl-cs.arpa
Thu Sep 19 20:36:20 AEST 1985


<<The line eater is alive and well and living in Europe>>

In the middle of the day we often run out of Ring (LAN) virtual terminal 
ports into our VAXes.  When the flurry of idle daemon programs came 
through a month or so ago, I looked at them and decided that they did
not suit our needs.  The idledaemon.c looked promising until I noticed
that it used an option for ps which does not exist in 4.2bsd.  Having
nothing better to do ((lies! they shout)) I had a go at writing a daemon
myself to solve our local problem.

The daemon tries to keep a small number of a pool of terminals (in this 
case ports) free for new sessions.  When there are not enough free
terminals, it checks for idle sessions, sends warnings and if necessary
kills sessions in order of decreasing idleness.  The daemon tries to
avoid annoying people by only killing idle sessions when there is a
shortage of free.

Sessions are only idle if there has been no terminal input, and if 
there are no active processes attached to the terminal.  The latter is  
determined by grubbing around in the process table, so the program is
4.2bsd specific.  (Sorry guys, but I was trying to make the daemon 
efficient ... 14 secs CPU in 18 hours, checking every 5 minutes ...)

Is anyone interested in having a copy of this program and the manual entry?
Please send mail to me personally.  I will post it to net.sources if there
is sufficient demand.


			Stephen C. Crawley

ARPA:	scc%cl.cam.ac.uk at ucl-cs.ARPA  SMail: Cambridge Univ. Computer Lab.,
JANET:	scc at uk.ac.cam.cl                     Corn Exchange Street,
UUCP:	{ukc,kcl-cs}!cl-jenny!scc	     Cambridge CB2 3QG, 
PHONE:	+44 223 352 435                      England.



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