In BS2000, there exist ‘single-feature pubsets’ (SF pubsets) and ‘system-managed pubsets’ (SM pubsets). SM pubsets are addressed in the same way as SF pubsets by way of their catalog ID.
An SF pubset comprises one or more disks which must be matching in respect of their essential characteristics (disk format, allocation unit, availability). By contrast, an SM pubset may comprise a number of so-called volume sets having differing characteristics. The essential characteristics of the disks only need to be matching within a volume set.
When a user specifies volume-set-specific characteristics for a file on an SM pubset, the system finds a volume set from the SM pubset which matches these characteristics and stores the file on that volume set. In this way it is possible, in particular, to move a file onto a volume having a different performance level within the same SM pubset without having to rename the file.
The utility SMPGEN is available to system administration for the generation of SM pubsets. This also allows a number of existing SF pubsets to be combined into an SM pubset.
This combination can only take place if there are no like-named files on the SF pubsets in question. There are certain exceptions to this condition such as the system catalogs of GUARDS, which contain the guards. Since they are entered under the same name on each SF pubset, on generation of an SM pubset they are combined by SMPGEN to form a single system catalog.
The combination of the GUARDS catalogs can only take place if no like-named guards exist. If this prerequisite is not met, the guards concerned must first be renamed by their owners.
When SF pubsets are combined to form an SM pubset, the path names which are defined in the access conditions PROGRAM are automatically adapted in the guards. The adaptation consists in replacing the catalog ID of the SF pubset with that of the SM pubset. When doing so, it is essential to observe the instructions which are described in the “Utility Routines” manual [15] under SMPGEN.
In order to recognize duplicate names and conflicts during the automatic correction of the path names, SMPGEN offers the facility to perform a check with logging of all conflict situations prior to the actual combination. This check can be performed both by system administration or by any other user.
For further information on SM pubsets, refer to the “SMS” manual [33].
For information on the SMPGEN refer to the manuals “Utility Routines” [15] and “SMS” [33].