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Note: This assumes that the autoinstall control program chooses not to
install a definition. If no definition is installed because autoinstall
fails, the dynamic routing program is not invoked.
Autoinstall processing of mapsets
Table 30 shows the differences in mapset processing between CICS regions with
program autoinstall active and inactive.
Table 30. Differences in mapset processing between autoinstall and non-autoinstall
Program autoinstall INACTIVE Program autoinstall ACTIVE
CSD definition is required. CICS attempts to
load a referenced mapset with a suffix. If this
fails, CICS tries an unsuffixed version. If that
is unsuccessful, abend APCT is issued.
CSD definition is not required. Using
autoinstall, CICS attempts to load the
referenced suffixed mapset or partitionset,
then the unsuffixed one. (In each case, a
definition is autoinstalled.) The transaction
requesting the resource abends only if no
version of the resource exists in the library,
either suffixed or unsuffixed.
If the suffixed mapset was not found in the
library, the definition is marked ‘not loadable’.
System autoinstall
Some programs are autoinstalled automatically (if they have not been statically
defined) by the CICS system autoinstall function, which does not require model
definitions or the support of the autoinstall control program. Programs in this
category include:
v First phase program list table post initialization (PLTPI) programs (that is, PLTPI
programs that are defined before the PLT table delimiter DFHDELIM).
v Second phase program list table shutdown (PLTSD) programs (that is, PLTSD
programs that are defined after the PLT table delimiter DFHDELIM).
Note: PLTPI programs that are defined after DFHDELIM, and PLTSD programs
that are defined before DFHDELIM, are treated like any other user
programs—they are eligible for program autoinstall.
Benefits of autoinstalling programs
Program autoinstall reduces system administration, virtual storage usage, and,
potentially, restart times.
Reduced system administration costs
Without autoinstall, you have to define all new programs, mapsets, and partitionsets
to CICS before they can be used. Autoinstall eliminates this requirement, enabling
these resources to be used without prior definition. Furthermore, the need to
maintain predefined definitions also disappears, leading to a significant saving in
system administration effort.
Saving in virtual storage
There is a saving in virtual storage within the CICS address space, as the
definitions of autoinstalled resources do not occupy table space until they are
generated.
Chapter 16. Writing a program to control autoinstall of programs 581