[This is preliminary documentation and subject to change.]
Logical media are abstract representations of partitions of physical media. All media that are currently in use in RSM are represented as logical media. You can use logical media to change a piece of physical media without changing the logical representation of the media. For example, you can replace media that is worn out by removing the old media and assigning the same logical media ID (LMID) to the new media.
Each logical medium maps to one partition of a physical medium. For example, a two-sided optical disk contains two partitions; each partition is represented by a different LMID. RSM applications can use LMIDs to mount, dismount, allocate, and deallocate media.
When a partition is allocated by an application, RSM changes its state from Available to Allocated and assigns LMID. Applications can only use allocated partitions. When media is deallocated, RSM disassociates the LMIDs from the logical media.