Some background on hung proceesses in NetWare:
If you freeze the Monitor, it's probably stuck on a critical process, like a file write or directory update. If you can identify the connection, you might get out of it killing the user. Usually you can't.
A hung NLM is likely also in a critical process, and trying to unload it compounds the problem by slaving the console to the hung process...
If the NLM is a service, you *might* want to let it go until you can reboot without an audience. If it's a critical service, like NDPS, SLP stuff, etc, you're going to lose users. Might as well reboot.
If the NLM is related to a storage device, there are soem other alternatives worth trying... SCSI adapters can often be unloaded and resolve a critical process for tape drives and CD-ROMs. Of course, disk drives are critical, reboot if this is the adapter. I use a dedicated adapter for tape drives to help with this. IDE drivers are more trouble than they are worth, get ready for the reboot.
Novell has some limited guidance on this. More than Microsoft.
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