>Subject:ADSM TAPE CAPACITY
>
>>>I have a question for you. I am currently using  ADSM MVS-SERVER VER.
>>>3.1.1.3 to backup on SILOS STK. I had define into device class
device=3490
>>>and maxcapacity=650Mb. In this situation the command Q VOLUME seem me
>>>maxcapacity=500Mb full. I don t undusted why.
>>>Can You help me?
>
>On VM and MVS servers MAXCAPACITY is the maximum amount of data that ADSM
will
>put on a tape, but if the tape becomes physically full, or has certain
errors,
>it will be marked full before it reaches that capacity.  The capacity
reported
>by ADSM does not consider compression.  If client compression is used, or
if
>the data is not very compressible (backups of zip files, for examples)
>then ADSM will report a full tape will a smaller capacity.  Most tape
>manufacturers give their tape capacity assuming compression (I think
normally
>around 3/1), so if you are sending already compressed data, you will not be
>able to reach the stated capacities.
>
>MAXCAPACITY, if set to other than 0 determines the maximum amount of data
>ADSM will put to a tape, ESTCAPACITY, if MAXCAPACITY is not set, is an
estimate
>used for some calculations for reclamation and display, but does not
determine
>when a tape is full. For further information on the MAXCAPACITY and
ESTCAPACITY
>parameters of the DEFINE and UPDATE DEVCLASS command, see the
Administrator's
>Reference, or use the online help.
>
>Carol Trible
>ADSM Development