There are some changes in the way that PDSE directories can be accessed for program libraries. They include:

• PDSE program object directory entries have been extended. Information about the type of member can be obtained via the directory entry, though not as directly as ISITMGD. (Multiple tests continue to be required because the program object indicator in a program directory entry is located in the same place as the user data field for a data directory entry.)
• You can still use BLDL to access PDSE program directory entries. The format is converted to the current format, with some modifications when the program object exceeds 16 meg.
• The IHAPDS mapping, which maps the PDS directory entry information returned by the BLDL macro, has changed in order to support program objects and accommodate the >16-Meg program objects.
  • There is a bit (PDS2LFMT) which indicates that the load module is a program object and that the PDS2FTB3 flags are valid and contain additional information.
  • There is a bit (PDS2BIG) that indicates that the length field (PDS2STOR) does not hold the module length and that the large load module extension exists. The PDS2VSTR field in this extension contains the fullword load module length in this case, and PDS2STOR contains a zero.
• A second directory service, DESERV, supports both PDS and PDSE libraries. You can issue DESERV for either PDS or PDSE directory access, but you must pass the DCB address. It does not default to a predefined search order, as does BLDL. DESERV returns an SMDE that, for PDSE directories, contains more information than is mapped by IHAPDS.
• You can still read PDSE Program Library directories using BSAM. The format of each directory entry will be converted, as is done with BLDL.
• As with all PDSE, one cannot access PDSE Program Libraries using EXCP.
• Applications that need to know if a data set is a PDSE program library can issue an external macro, ISITMGD, to get this information. The data set must be open at the time. This macro is documented in z/OS DFSMS Macro Instructions for Data Sets and also discussed in z/OS DFSMS Using Data Sets.