Supplying system initialization parameters to CICS

The CICS® parameter manager domain loads a system initialization table (SIT) at the start of the initialization process.

About this task

You specify the SIT that defines the CICS characteristics appropriate to your needs by coding the suffix of the DFHSITxx load module (where xx is the suffix) on the SIT= system initialization parameter. If you fail to specify the suffix of a SIT, then CICS tries to load an unsuffixed module.

You can modify many of the system initialization parameters dynamically at the beginning of CICS initialization by providing system initialization parameters in the startup job stream, or through the system console. There are also some system initialization parameters that you cannot code in the SIT, and can only supply at startup time. You specify system initialization parameters at startup time in any of three ways:
  1. In the PARM parameter of the EXEC PGM=DFHSIP statement
  2. In the SYSIN data set defined in the startup job stream
  3. Through the system operator's console
You can use just one of these methods, or two, or all three. However, CICS processes these three sources of input in strict sequence, as follows:
  1. The PARM parameter
  2. The SYSIN data set (but only if SYSIN is coded in the PARM parameter; see SYSIN)
  3. The console (but only if CONSOLE is coded in either the PARM parameter or in the SYSIN data set; see CONSOLE(CN))
Note: If you supply duplicate system initialization parameters, either through the same or a different medium, CICS takes the last one that it reads. For example, if you specify MCT=1$ in the PARM parameter, MCT=2$ in the SYSIN data set, and finally enter MCT=3$ through the console, CICS loads DFHMCT3$.