Explanation/Reference:
Explanation:
EXPIRED and AVAILABLE Status
You can view the status of backup sets and copies recorded in the RMAN repository through LIST, vs views, or recovery catalog views (if you use RMAN with a catalog). Table 2-4 describes the meaning of each status.
The crosscheck command only processes files created on the same device type as the channels used for the crosscheck. The crosscheck command checks only objects marked available or expired in the repository by examining the files on disk for disk channels or by querying the media manager for sbc channels.
The CROSSCHECK command only processes files created on the same device type as the channels used for the crosscheck. The CROSSCHECK command checks only objects marked AVAILABLE or EXPIRED in the repository by examining the files on disk for DISK channels or by querying the media manager for sbt channels.

CROSSCHECK
Purpose
Use the CROSSCHECK command to synchronize the physical reality of backups and copies with their logical records in the RMAN repository.