In an SMS environment, an SM pubset containing volume sets with different attributes is the equivalent of various SF pubsets with different attributes made available to the users of a computer center for distributing their files. As with SF pubsets, the predefined catalog ID (catid) in the path name of a file determines which pubset it is stored on. Thus, selecting a suitable SF pubset corresponds to selecting a suitable volume set of an SM pubset.
The location of files in an SM pubset can be influenced by various instruments such as direct specification of file attributes, storage classes and physical allocation. These can be used simultaneously within an SM pubset.
The file attributes performance, structure, availability and work file enable users to specify their requirements directly. The system then selects the suitable volume set in accordance with the specified file attributes.
Storage classes are named combinations of individual attributes. They offer a more convenient way of specifying the desired file attributes. As with direct specification of file attributes, the system then selects the suitable volume set in accordance with the specified storage classes.
Physical allocation enables users to define a specific location within the public disks of an SM pubset.
The following sections first describe an environment which exclusively uses direct attribute specification. Then storage classes are presented as an extended form of direct attribute specification. Finally, the part physical allocation can play in the utilization of an SM pubset is described.