uVAX 3900 out to lunch after inactivity

It's me who should have been clearer. Do the REPLY /ENABLE and friends before the problem shows up in the hope of seeing a message giving details about the problem when it does show up. You might see something like "Mount verification is in progress." for example. Do the SHOW ERROR anytime and if anything (other than a tape drive, terminal or any sort of virtual device) shows a non-zero error count, investigate the reason for it. Particularly watch for MEMORY or CPU errors. If your disk device starts clocking errors just before the system stalls, that would tend to point the finger in its direction. $ SHOW SYSTEM is the one command I know of that will usually execute when almost all others fail due to resource starvation. Using it to look at what states processes are in will give clues about what resources they might be waiting for. The numbers will vary depending on your hardware and configuration. What matters is that that "Free space" is not approaching zero when "Current size" is already as big as "Maximum size" which means there is no scope for further automatic expansion of the pool size. If you have plenty of free space, you are ok. If you don't have any free space but "Current size" is less than "Maximum size", you are still ok. Another approach to this sort of thing is to crash the system when it becomes unresponsive and analyse the resultant crash dump afterwards. Probably better to try the AUTOGEN first though. Regards, Peter Coghlan.