3.2.1.2.2 Media Pools
A media pool is a logical collection of media that share some common attributes. A media pool contains media of only one type, but media in the media pool can be in more than one library. Every cartridge is in a media pool.
There are two classes of media pools: system and application. System media pools are created by the RSM for its own use and include the free, import, and unrecognized pools. Application media pools are created by applications to group media. Grouping media is especially important if several applications are sharing the libraries attached to a system and the media they contain.
Each media pool has access permissions that control access to the media that belong to the pool. While these permissions do not control access to the data contained on the media, they do control the manipulation of the media, including an application's ability to move media from the pool or to allocate media for its own use.
Media pools can be used hierarchically. A media pool can be used to hold other media pools, or it can be used to hold media. An application that needs to group media of several types into one collection can create an application media pool for the whole collection, and additional media pools within it, one for each media type. RSM actually uses this technique for its system pools. Within the free pool, for example, is a media pool for each media type.
Both sides of a two-sided cartridge are to be in the same pool.
The possible types of media pools include system pools, free pools, unrecognized pools, import pools, and application pools.