Machines locking up - NFS related

[Yampalimardilor]

Our DECstations running Ultrix 4.0 have a problem - if an NFS server
goes down, and one of its disks is mounted, the machine locks up.
Especially if no-one is logged in - Xprompter goes away.
Is there some way to tell mount that if an NFS server goes down, just
don't access that disk?  (note:  the bg option in /etc/fstab doesn't
seem to help - only when initially mounting the disk)

Thanks.
		-Devin

***********************************************************************
* Yampalimardilor          *     a.k.a Devin Hooker (RP90) DoD # 0034 *
* Mage School, Glantri     *           University of Colorado-Boulder *
* (Master of Movement)     *           (Undergrad Student)            *
***********************************************************************