>Richard I cant see any parameters in the update volume command to reset the
>mount number!

True: We would all like it to provide that capability, but it doesn't.

>What is a checkout/ checkin sequence ??

That's where you use the 'CHECKOut LIBVolume' command to momentarily remove
the volume from "being in the library", from ADSM's point of view, and then
logically put it back via 'CHECKIn LIBVolume'.
    Richard