CLPA

CLPA

(See also the MLPA parameter for temporary additions to the LPA, and the CVIO parameter for the deletion of VIO data sets.) This parameter causes NIP to load the LPA with all modules contained in the LPALST concatenation. Modules listed in the specified LPA pack list member (IEAPAKxx) are packed together, preferably in one-page groups. (See description of IEAPAKxx.) Modules not in the pack list are loaded in size order, large modules first, then smaller modules to fill unused space.

PLPA pages are written to auxiliary storage. Only one set of PLPA pages can exist in paging space. Modules in the LPALST concatenation must be reenterable and refreshable because the system uses the processor's page protection facility, which enforces read-only access to each PLPA page.

CLPA should be specified after the installation has modified a data set in the LPALST concatenation and wants to reload the PLPA with new or changed modules.

Note: CLPA also implies CVIO, so that VIO data set pages on local page data sets are automatically purged. (See the description of CVIO for further information.)

The CLPA parameter is not needed at the first IPL. NIP detects the cold start condition internally, noting that the PLPA has not been loaded.

If CLPA is not specified, NIP tries to find a usable PLPA in the existing page data sets. If NIP is successful, a quick start or a warm start occurs, and the auxiliary storage manager (ASM) obtains the records that specify where the PLPA pages reside on auxiliary storage. It then reestablishes the previous set of PLPA pages. The old PLPA may be reused for any number of system initializations, if CLPA is not specified. However, page data sets that contain the last used set of PLPA pages must be mounted. If they are not, the operator is asked to mount them. If the operator bypasses mounting, ASM initialization requests a different page data set and forces a “cold” start. NIP then reestablishes the PLPA as it does when CLPA is specified. In this cold start, both the previously established PLPA and existing VIO data set pages are logically deleted from paging space.

The fixed LPA and the modified LPA, however, are not automatically reused in a quick start or a warm start. They must be respecified. Existing VIO data set pages on local page data sets are retained in a warm start, unless the CVIO or CLPA parameter is forced. Such pages are not retained in a quick start or a cold start. (See the description of the CVIO parameter.)

If CLPA is specified and a set of PLPA pages already exists on a paging data set, NIP frees the existing PLPA and updates the appropriate records to reflect the new PLPA pages on auxiliary storage. NIP loads the LPA from the LPALST concatenation, as previously described.

IBM® suggests that you have an IEASYSxx member that does not specify CLPA. This permits you to load the initial program without rebuilding the PLPA if it is not possible to access your LPA data sets.

Value Range: Not applicable

Default Value: Not applicable

Associated Parmlib Member: None