z/OS MVS Initialization and Tuning Guide
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The fixed link pack area (FLPA)

z/OS MVS Initialization and Tuning Guide
SA23-1379-02

An installation can elect to have some modules that are normally loaded in the pageable link pack area (PLPA) loaded into the fixed link pack area (FLPA). This area should be used only for modules that significantly increase performance when they are fixed rather than pageable. Modules placed in the FLPA must be reentrant and refreshable.

The FLPA exists only for the duration of an IPL. Therefore, if an FLPA is desired, the modules in the FLPA must be specified for each IPL (including quick-start and warm-start IPLs).

It is the responsibility of the installation to determine which modules, if any, to place in the FLPA. Note that if a module is heavily used and is in the PLPA, the system's paging algorithms will tend to keep that module in central storage. The best candidates for the FLPA are modules that are infrequently used but are needed for fast response to some terminal-oriented action.

Specified by: A list of modules to be put in FLPA must be established by the installation in the fixed LPA list (IEAFIXxx) member of SYS1.PARMLIB. Modules from any partitioned data set can be included in the FLPA. FLPA is selected through specification of the FIX system parameter in IEASYSxx or from the operator's console at system initialization.

Any module in the FLPA will be treated by the system as though it came from an APF-authorized library. Ensure that you have properly protected any library named in IEAFIXxx to avoid system security and integrity exposures, just as you would protect any APF-authorized library. This area may be used to contain reenterable routines from either APF-authorized or non-APF-authorized libraries that are to be part of the pageable extension to the link pack area during the current IPL.

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