System Installation Choices › Parameter Library › Alternate General Parmlib Members

Alternate General Parmlib Members

The console operator can specify alternate general members at IPL in response to the ENTER SYSTEM PARAMETERS prompt. For example, the operator can enter SYSP=xx, where xx is the two‑character suffix of an alternate general member, such as IEASYS01.

The operator can also supply a series of alternate general member suffixes. For example, the operator could enter SYSP=(01,02,04) in response to the ENTER SYSTEM PARAMETERS prompt.

Each member is processed, working from left to right, always starting with the master general member (IEASYS00) and examining each of the alternate general members (IEASYSxx) that contain overrides to the master general member.

IPL parameters can specify a LOADxx member from (searched in this order):

• SYS9.IPLPARM on the IODF volume
• SYS1.PARMLIB on the IODF volume
• SYS1.PARMLIB on the SYSRES volume

The LOADxx member can specify alternate general parmlib members similar to the operator SYSP response. In many cases, this may be the preferred approach to minimize operator intervention.

The system forms a consolidated list of general member parameters and specialized member references as follows:

• The consolidated list is initialized with the contents of the master general member, IEASYS00.
• The system examines the alternate members and adds the parameters and specialized member references that were not mentioned in the master member to the consolidated list.
• If the system finds a reference that is already in the consolidated list, it replaces the entry in the list with the reference in the alternate member.

Many data centers have only one or two IEASYSxx alternate general members in a single, centralized library. However, other sites may choose to use a common logical Parmlib data set for common parameters that are used by all CPU’s in a complex, and then use unique logical Parmlib data sets for those parameter members that are unique to each CPU. In any event, the data center staff should have adequate documentation that defines the purpose, use, and function of each alternate general parameter member as well as the data sets which comprise the logical Parmlib concatenation as a whole.