Computer Drive User Manual

VV Condition controls the availability of the volume for the following actions:
• Creation of new storage segments
• Reading of existing storage segments
• Writing of existing storage segments
• Mounting of tape media
Tape volumes have six possible settings for VV Condition:
• RWC - Read, Write, Create
• RW - Read/Write
• RO - Read Only
• EOM - End of Media reached
• EMPTY – The volume reached EOM, and all data has been removed.
• DOWN - Volume not available
Disk volumes have five possible settings for VV Condition:
• RWC - Read, Write, Create
• RW - Read, Write
• RO - Read Only
• EMPTY – The volume is in RO condition and all data has been removed.
• DOWN - Volume not available
A volume in RWC condition is fully enabled for use. This is the normal setting for all disk volumes and
for tape volumes that have not reached EOM. Storage segments can be created on the volume; existing
segments can be read and written. Volumes in RWC condition can be changed to any other condition.
Existing storage segments on disk volumes in RW condition can be read and written, but new segments
cannot be created. This setting is useful for emptying a disk through attrition. Disk volumes can be
emptied more quickly by setting the Condition to RW, then purging or repacking the disk. Volumes in
RW condition can be changed to any other condition except as limited by the Retire flag (see below).
RO condition is similar to RW condition, but writes to existing disk storage segments are not permitted.
Storage segments on tape volumes in RO condition can be read, but not written. New segments cannot be
created. Tapes in RO condition are similar to tapes in EOM condition with the exception that their
condition can be changed to RWC or RW while tapes in EOM condition cannot. Volumes in RO
condition can be changed to any other condition except as limited by the Retire flag (see below).
RW condition is similar to RO condition, but allows the last segment of a tape volume to be written as
long as it remains writable. Note that only the last storage segment on a tape volume may be writable,
while all the others are never writable.
Tape volumes enter EOM condition when the end of media marker is reached while writing the tape or
when the administrator sets the Condition to EOM. EOM condition is similar to RO condition - segments
HPSS Management Guide November 2009
Release 7.3 (Revision 1.0) 279