[mod.computers.vax] VMS swapper question

levy.RDES@XEROX.COM (09/10/86)

Does anyone out there know how the swapper is supposed to work?
Specifically,
if it has to choose between swapping a process that has been in HIB for
less
than "LONGWAIT", or a process that has been in LEF for more than
"LONGWAIT", 
which is it supposed to choose?  The documentation for the swapper is
long on generalizations but short on specifics.

My site has a 785 used by 30-35 people, a few of whom like to login
first thing
in the morning, invoke Datatrieve, then ignore the VAX for the rest of
the day.
My response is to keep the balance set count low (38) and set LONGWAIT
to 5
minutes, forcing the swapper to swap out inactive interactive processes
to
free the memory for others.  This worked reasonably well under VMS
V4.0-V4.3,
but under VMS V4.4 "busy" hibernating processes such as the job
controller are
repeatedly swapped in and out (sometimes many times per minute), while
inactive
processes in the LEF state remain memory-resident.

Note that while my impression is that this change occurred when we
upgraded
to V4.4, I have not gone back and reinstalled V4.3 to verify the problem
was not caused by some other change that occurred at about the same
time.

As a related question, is there any supported way to disable
process-swapping
for the job controller.  (I don't want to modify STARTUP.COM.)

Any information on this subject would be appreciated.

				B. Levy / Versatec

carl@CITHEX.CALTECH.EDU (09/14/86)

The following code, placed early in SYS$MANAGER:SYSTARTUP.COM, should cause
job_control to run with swapping disabled, without altering any of the files
DEC claims you shouldn't.
------------------------------------------------------------------------------
$ stop JOB_CONTROL
$ run :== run/noswap
$ @sys$system:startup jobctl
$ delete/symbol/global run