VMS7.3 dismount of a device with pagefile before shutdown?

Peter Coghlan cctalk at beyondthepale.ie
Mon Aug 24 13:11:38 CDT 2015

Holm Tiffe wrote:
> Hi,
> I've managed to relaocate the pagefile.sys of my VMS7.3 to the secondary
> disk disk1$dia1 because of space considerations of the first disk (380MB
> total, free blocks 228672 now).
> I've seen complaints of the system that the disk wasn't properly dismounted
> after each reboot and would be rebuild. A hint from my friend Vaxman was,
> to mount the disk with the option /NOREBUILD in SYPAGSWPFILES.COM so it
> looks like this now:
> $ EXIT
> Is there an other way to properly dismount the drive at the shutdown?

If you are using @SYS$SYSTEM:SHUTDOWN to shut down, this should issue a
disk that is mounted.  However, this only marks the disk for dismount and the
disk might not actually get dismounted if there are processes still accessing
files (including the pagefile) on the disk by the time the CPU is halted.

You might see some messages at shutdown time saying that the disk has been
marked for dismount or maybe there might be a message saying it couldn't be

It works ok for me with VAX/VMS 5.5-2 on a VAXstation 3100 but I have a pagefile
on the system disk as well as a pagefile on a second disk and this setup may
be less likely to end up with a system process which cannot be stopped grimly
hanging on to the pagefile on the second disk at shutdown time (because the
system processes will most likely get pagefile allocations in the pagefile on
the system disk, not the pagefile on the second disk.) 

> My home directory lives on the 2nd disk too..and I think /NOREBUILD
> supresses the warning message, but not the problem at all..

The /NOREBUILD means don't rebuild the free space cache.  If the free space
cache is not rebuilt after the disk is improperly dismounted, the result is
that not all of the free space on the disk will be available for use.  There
will not be damage to the filesystem or data loss.  The missing free space
can be recovered using SET VOLUME /REBUILD at some more convenient time after
booting instead of having MOUNT /REBUILD hold up the boot process.

Peter Coghlan.

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