The following describes the program object access modifications and restrictions:

• The program object can be accessed for input using the SAM access method, though this is not recommended. While 4KB blocks will be presented to the user, no description of these blocks will be available. (This access is provided primarily for browse and compare services, where there is no need to interrogate or understand the format of the data.)
• No user can access a PDSE program library directly for output. This function is reserved exclusively for the binder. Services that perform output functions, for example, AMASPZAP, must invoke the binder. Applications can use the binder API to put data into a program object.
• Program objects must reside in either PDSEs or z/OS UNIX files. Data members and program objects may NOT reside in the same PDSE. The PDSE type is determined by the data type on issuance of the first STOW into an empty PDSE.
• There are no “dangling aliases” for program objects in PDSEs. When the primary member name is deleted or replaced, the old aliases are deleted automatically.
• The DCB RECFM field for PDSE program libraries must be specified the same as it is now for PDS program libraries, for example, RECFM=U (undefined record format). While this has no meaning in terms of the actual program object record format, traditionally it has helped to identify program libraries. To promote transparency and usability, this record format will continue to be required as one of the program library indicators for PDSEs as well as PDS's.