Benefits of using the MVS link pack area

There are several benefits of placing code in the MVS link pack area.

  • You protect the code from possible corruption by user applications. Because the MVS link pack area is in protected storage, it is virtually impossible to modify the contents of these programs.
  • You can improve the performance, and reduce the demand for real storage, if you use the MVS link pack area for program modules. If more than one copy of the same release of CICS® is running in multiple address spaces of the same processor, each address space requires access to the CICS nucleus modules. These modules can either be loaded into each of the address spaces or shared in the MVS link pack area. If they are shared in the MVS link pack area, the working set and, therefore, the demand for real storage (paging) can be reduced.
  • You can decrease the storage requirement in the private area by careful allocation of the unused storage in the MVS link pack area created by rounding to the next segment.

    If you know the amount of space that you require in the LPA, and from that the total size of the MVS common area above the CICS private storage, you can determine the 1 MB segment on which the boundary between the two areas lies. This calculation might indicate some space in the MVS common area is left unused, which you can use for CICS LPA-eligible modules. By moving more modules from CICS private storage to the LPA, you decrease the space that is required for modules in CICS private storage.