The program management loader increases the services of the program fetch component by adding support for loading program objects. The program management loader reads both program objects and load modules into virtual storage and prepares them for execution. It relocates any address constants in the program to point to the appropriate areas in virtual storage and supports 24-bit, 31-bit, and 64-bit addressing ranges.

All program objects loaded from a PDSE are page-mapped into virtual storage. When loading program objects from a PDSE, the loader selects a loading mode based on the module characteristics and parameters specified to the binder when you created the program object. You can influence the mode with the binder FETCHOPT parameter. The FETCHOPT parameter allows you to select whether the program is completely preloaded and relocated before execution, or whether pages of the program can be read into virtual storage and relocated only when they are referenced during execution. (See FETCHOPT: Fetching mode option for more information on the FETCHOPT parameter.) z/OS UNIX System Services are called to load a program object from a z/OS UNIX file.