CICS startup

This section describes how to start up CICS® in the CICS region. Depending on your system environment, you can start the CICS job from a procedure by using the START command, or you can submit the CICS startup job stream through the internal reader. This section gives an example of each of these methods. For an example of a batch job that you can submit through the internal reader, see A sample CICS startup job. A sample CICS startup procedure gives an example of a cataloged procedure suitable for starting CICS as a started task.

When you run the startup job, you start a process called CICS system initialization. This process must finish before you run any transactions. Completion of CICS initialization is shown by the following message at the system console:

DFHSI1517 - applid:  Control is being given to CICS.

CICS initialization involves many activities, some of which are:

Also, if you are operating CICS with CICS recovery options, backout procedures may be used to restore recoverable resources to a logically consistent state. Briefly, backout occurs if you start CICS in one of the following ways:

For background information about backout, and recovery and restart, see the CICS Recovery and Restart Guide.

In the final stages of initialization, a set of programs can be executed as specified in a program list table (PLT). You specify the suffix of the PLT you want by means of the PLTPI parameter in the SIT. Initialization PLT programs run under control of a CICS task in CICS key. Their storage is in CICS-key storage, and protected from overwriting by other transactions.

Start of changeThe PLTPI resource managers start up in the following sequence when specified in the system initialization table:End of change

  1. CPSMCONN=CMAS
  2. CPSMCONN=LMAS
  3. CPSMCONN=WUI
  4. DBCTLCON=YES
  5. DB2CON=YES
  6. MQCON=YES

Start of changeThis sequence only applies to the above system initialization parameters and not for PLTPI programs in general.End of change

For more information about storage protection, see Storage protection. For programming information about writing PLT programs, see the CICS Customization Guide.

If you are running CICS with DB2®, you can specify the DB2 subsystem ID to be used at PLT startup by the INITPARM system initialization parameter, as follows:

INITPARM=(DFHD2INI='yyyy')

where yyyy is the 4-character DB2 subsystem ID. The value must conform to MVS™ JCL rules about special characters. You cannot use the ID of a data sharing group of DB2 subsystems on the INITPARM system initialization parameter -- you must specify the ID of a single DB2 subsystem. If you want to use the INITPARM system initialization parameter to specify a DB2 subsystem, leave blank both the DB2GROUPID and the DB2ID in the installed DB2CONN definition. An ID specified in either of these attributes of the DB2CONN definition overrides an ID specified on the INITPARM system initialization parameter.

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