Various system requirements, although not involving explicit parameters,
affect the way the system performs. These system requirements may
be considered as “implicit” parameters. They involve DD statements,
data sets, hardware choices, and so forth. Some examples are:
- SYSABEND, SYSMDUMP, and SYSUDUMP DD statements. Without these
statements, the parameters in parmlib members IEAABD00, IEADMR00,
and IEADMP00 and the dump option lists in ABEND macro instructions
are meaningless because an ABEND dump cannot be taken.
- The SMF data sets. If these data sets are not allocated on direct
access volumes and cataloged, no SMF recording occurs.
- Addition of new modules to the LPALST concatenation through use
of IEBCOPY, the Linkage Editor or the binder. Adding new modules affects
the size and usefulness of the PLPA that is loaded by specifying the
CLPA parameter at IPL.
- Choice of the device on which the PLPA paging data sets will reside.
This choice affects the speed at which PLPA modules can be paged into
storage and thus influences system performance.
- Definition of page data sets through the DEFINE PAGESPACE command.
The PAGE parameter, issued at IPL through parmlib and/or the operator,
is significant only if the specified data sets have been previously
formatted by the DEFINE PAGESPACE command. (For information about
this command, see z/OS DFSMS Access Method Services Commands.)