Quantum M1500 Library leaving tapes mounted after backup completion

I think now in v7.3 even in plain config if you change idle device timeout from 0 any other value it will unmount tapes - at least on my configuration. I don't know if it is a new behaviour in v7.3 but it is worth trying.

In 7.3 LCP was taken from SM/AS (or at least part of it) which is now nsrlcpd daemon. I did hear reports were it was suggested unmounts would happen. I did observe this once while testing something else where my idle device timeout was 4 and unmount did not happen for 15 minutes - after that I did manually unload the tape (as I had to carry on with my test).

This would then suggest that the "Idle Device Timeout" option was now part of the device configuration, not jukebox... as if there was the ability that v7.3 could 'unmount' devices not in a jukebox, then no jukebox idle device timeout could affect them......

if thats true, does one override the other, and if so, which one......

I believe we are talking about devices belonging to jukebox only here. To unmount standalone device you would need to use nsrmm command (nsrmm -uv -f /path/to/drive). I believe both unmount (-u) and eject (-j) were manual operation before. Not sure, but I would assume same is now (can't see why would that change except maybe when tape reached its physical end - that would be nice feature even standalone devices are not that used these days). Idle device timeout is parameter which applies to libraries and not devices alone.