We are running ADSM V1 server on MVS.

When looking through the Admin GUI under Storage Pool Volumes, it shows
some tape volumes as having a different estimated capacity than others,
e.g :

Estimated Capacity (MB) Percent Utilised
428                             100
726                             53
673                             100
660                             49

We have one DEVCLASS for all tapes, which are all in a tape library.
The Estimated Capacity we specified when setting up the DEVCLASS was
800MB.

Can someone please explain what these figures actually mean and why they
appear to vary.