z/VSE LIBR Service

To access VSE Libraries we need a mechanism to translate the dataset names in UEDTB1 to a filename. For this an internal file table with filename, dataset name and volser is created during startup. The table is expanded whenever a Com-plete utility attempts to access a library that does not yet have information in the file table.

The program U2SPIT, which must be specified in the sysparms (STARTUPPGM=U2SPIT), allocates storage for the file table based on the number specified in the sysparm MAXLIBS.

Note:
The specification of STARTUPPGM=U2SPIT is required for VSE.

U2SPIT will call TLSPDSN to build the file table at initialization of Com-plete. TLSPDSN does the following:

  • Processes the TEMP and PERM LIBDEF SEARCH chains. From the label entries for the libraries an entry is built in the file table with the required information.

  • Processes UEDTB1 and builds new entries for libraries that were not in any of the LIBDEF CHAINs. If there is no label available in the partition’s TEMP or PERM, a new one will be created from the UEDTB1 information.

The program TLSPDSN is also called during Com-plete execution by utilities requiring that a File-Id must be related to a dataset name and volser, which are specified by the user (via utilities such as USERV, UEDIT, and UED). If the dataset name is not in the file table, TLSPDSN will add a LABEL to the PARTITION TEMPORARY LABEL AREA and build a new entry in the file table (after verifying that the filename specified belongs to a valid library).

Note:
In order to access VSAM libraries, it is necessary to have them defined by either UEDTB1 or function UL of UUTIL.