Link Pack Area (LPA)

  • It’s a common Virtual Storage Area.
  • It’s non-getmainable.
  • It’s built at IPL time by loading Load modules contained in SYS1.LPALIB and its concatenations.
  • There are 2 LPAs: one above “the line” (16MB) and the other below depending on the residence mode of the load module.
  • Because the Load modules are in the Common Area they are shared by all address spaces in the system.
  • Modules have to be re-entrant, ie, modules that can be executed concurrently by several tasks but which cannot be modified.
  • Modules in LPA reside in Virtual Storage.
  • By placing module data sets in LPA, you can obtain improved MVS system performance.
  • LPA consists of:
    • PLPA – Pageable Link Pack Area (defined in SYS1.PARMLIB(LPALSTxx))
    • FLPA – Fixed Link Pack Area (defined in SYS1.PARMLIB(IEAFIXxx))
    • MLPA – Modified Link Pack Area (defined in SYS1.PARMLIB(IEALPAxx))
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One Response to “Link Pack Area (LPA)”

  1. [...] program protection loads re-entrant programs into read-only storage similar to z/OS link pack area. This is not as simple as it sounds, since some programs may cause problems because they modify [...]

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