Using system initialization control keywords

You can use the following control keywords at startup to control how CICS® is to read system initialization parameters:

  1. SYSIN (or SI for short)
  2. CONSOLE (or CN for short)
  3. .END

The purpose of these special keywords, and where you can code them, are described as follows:

SYSIN (SI)
This keyword tells CICS to read initialization parameters from the SYSIN data set.

Where to code SYSIN:   You can code SYSIN (or SI) only in the PARM parameter of the EXEC PGM=DFHSIP statement. The keyword can appear once only and must be at the end of the PARM parameter. CICS does not read SYSIN until it has finished scanning all of the PARM parameter, or until it reaches a .END before the end of the PARM parameter. (See .END in topic END.)

Examples:

//stepname   EXEC  PGM=DFHSIP,PARM='SIT=6$,SYSIN,.END'
//stepname   EXEC  PGM=DFHSIP,PARM='SIT=6$,DLI=YES,SYSIN,.END'
CONSOLE (CN)
This keyword tells CICS to read initialization parameters from the console. CICS prompts you with message DFHPA1104 when it is ready to read parameters from the console.

Where to code CONSOLE:   You can code CONSOLE (or CN) in the PARM parameter of the EXEC PGM=DFHSIP statement or in the SYSIN data set. This keyword can appear either at the end of the PARM parameter or in the SYSIN data set, but code it in one place only.

If you code CONSOLE (or CN) in the PARM parameter, and PARM also contains the SYSIN keyword, CICS does not begin reading parameters from the console until it has finished reading and processing the SYSIN data set. Similarly, wherever you place the CONSOLE keyword in the SYSIN data set, CICS does not begin reading parameters from the console until it has finished reading and processing the SYSIN data set.

Examples:

//stepname   EXEC  PGM=DFHSIP,PARM='SIT6$,CONSOLE,.END'
//stepname   EXEC  PGM=DFHSIP,PARM='CONSOLE,SYSIN,.END'
//stepname   EXEC  PGM=DFHSIP,PARM='SIT=6$,CN,SI,.END'
Note:

If both SYSIN (or SI) and CONSOLE (or CN) appear as keywords of the PARM parameter, the order in which they are coded is irrelevant as long as no other keywords, other than .END, follow them.

.END
The meaning of this keyword varies:
PARM
The use of the .END keyword is optional in the PARM parameter. If you omit it, CICS assumes it to be at the end of the PARM parameter. If you code .END in the PARM parameter it can have one of two meanings:
  1. If you also code one, or both, of the other control keywords (CONSOLE and/or SYSIN) .END denotes the end of the PARM parameter only.

    For example:

    //stepname   EXEC  PGM=DFHSIP,PARM='SIT6$,SI,CN,.END'
  2. If you code .END as the only control keyword in the PARM parameter, it denotes the end of all system initialization parameters, and CICS begins the initialization process. For example:
    //stepname   EXEC  PGM=DFHSIP,PARM='SIT=6$,.END'

If .END is not the last entry in the PARM parameter, CICS truncates the PARM parameter and the parameters following the .END keyword are lost.

SYSIN
The use of the .END keyword is optional in the SYSIN data set. If you omit it, CICS assumes it to be at the end of SYSIN. If you code .END in the SYSIN data set its meaning depends on your use of the CONSOLE keyword, as follows:
  • If you code the CONSOLE control keyword in the PARM parameter or in the SYSIN data set, .END denotes the end of the SYSIN data set only.
  • If you do not code the CONSOLE control keyword in the PARM parameter or in the SYSIN data set, .END denotes the end of all CICS system initialization parameters, and CICS begins the initialization process.

If you code .END, and it is not the last entry in the SYSIN data set, or not at the end of a SYSIN record, CICS initialization parameters following the .END are ignored. To avoid accidental loss of initialization parameters, ensure that the .END keyword is on the last record in the SYSIN data set, and that it is the only entry on that line. (However, if you want to remove some system initialization parameters from a particular run of CICS, you could position them after the .END statement just for that run.)

The following example shows the use of .END in a SYSIN data set:

//SYSIN   DD  *
* CICS system initialization parameters
SIT=6$,START=COLD,
* XRF=NO,            ( XRF this run - SIT defines XRF=YES
PDIR=1$,             ( SUFFIX of PSB directory

  ·
  ·
  ·
.END /*
CONSOLE
The meaning of .END through the console depends on whether you are entering new parameters or entering corrections. The two meanings are as follows:
  1. If you are keying new parameters in response to message DFHPA1104, .END terminates parameter reading, and CICS starts initialization according to the SIT it has loaded, but modified by any system initialization parameters you have supplied. Until you enter the .END control keyword, CICS continues to prompt you for system initialization parameters.
  2. If you have coded PARMERR=INTERACT, and CICS detects a parameter error, either in the keyword or in the value that you have assigned to it, CICS prompts you to correct the error with message DFHPA1912 or DFHPA1915. If you enter the correct keyword or value, initialization resumes with CICS continuing to process either the PARM parameter, the SYSIN data set, or prompting for more system initialization parameters through the console, depending on where CICS detected the error. If you cannot correct the error, but want CICS to continue with the initialization process, you can enter .END to end the error correction phase.

Processing the PARM parameter

If you omit the PARM parameter from the EXEC PGM=DFHSIP statement, CICS assumes that there are no SIT override or other initialization parameters, and tries to load an unsuffixed module named DFHSIT. As a general rule, this is unlikely to be your intention, so the PARM parameter should at least specify the suffix of your system initialization table, using the SIT keyword. Alternatively, you can code the special SYSIN keyword as the only PARM parameter, and supply the suffix of your SIT and the other system initialization parameters from the SYSIN data set.

CICS scans the PARM string looking for a SIT= parameter, any of the special control keywords, or any system initialization parameters, and proceeds as follows:

Rules for coding PARM parameters

The rules for coding the PARM parameter on an EXEC job control statement are described fully in the OS/390 MVS JCL Reference manual. Briefly, the maximum number of characters you can code is 100, excluding the opening and closing delimiters, which can be either apostrophes or parentheses. All CICS system initialization parameters must be separated by a comma, and the separating commas are included in the 100 character limit. Because of this limiting factor, you might prefer to limit the use of the PARM parameter to specify the SYSIN control keyword only.

Processing the SYSIN data set

CICS scans the SYSIN data set looking for a SIT= parameter and any of the special keywords, as well as system initialization parameters.

If CICS finds a SIT= parameter in SYSIN, it tries to load that SIT, overriding any that was specified in the PARM parameter. If CICS does not find a SIT= parameter in SYSIN, it tries to load any SIT specified in the PARM parameter.

However, if after scanning the PARM parameter and the SYSIN data set CICS has not found a SIT= parameter, CICS does one of the following:

  1. If you specified CONSOLE in the PARM parameter or in the SYSIN data set, CICS prompts you with the following message to enter the SIT suffix as the first parameter through the console:
    rr DFHPA1921  DBDCCICS  PLEASE SPECIFY THE REQUIRED SIT SUFFIX, OR
                            SPECIFY 'NONE'(UNSUFFIXED).
  2. If you did not specify CONSOLE, CICS tries automatically to load an unsuffixed SIT module (DFHSIT). If this load fails, CICS issues message DFHPA1106, requesting a SIT suffix in reply to the message.
Note:
CICS does not process any system initialization parameters that are coded in the PARM parameter and the SYSIN data set until after the SIT has been loaded.

Rules for coding CICS system initialization parameters in the SYSIN data set

There are a few rules to observe when coding CICS system initialization parameters in the SYSIN data set. These are:

Processing the console entries

Generally, CICS does not begin to read from the console until it has loaded the SIT and processed any initialization parameters that are coded in the PARM parameter and the SYSIN data set. CICS accepts system initialization parameters from the console until you terminate the input with .END.

You can specify a SIT= parameter only as the first parameter through the console when prompted by message DFHPA1921, at which point CICS tries to load the specified SIT. If you try to specify a SIT= parameter after CICS has loaded the SIT it is rejected as an error.

Rules for coding CICS system initialization parameters at the console

When it is ready to read parameters from the console, CICS displays the following message (where nn is the reply ID):

nn DFHPA1104 applid - SPECIFY ALTERNATIVE SIT PARAMETERS, IF ANY,
                      AND THEN TYPE '.END'.

You can enter as many initialization parameters as you can get on one line of the console, but you must use a comma to separate parameters. CICS continues to prompt for system initialization parameters with displays of message DFHPA1105 until you terminate console input by entering the .END control keyword.

Entering corrections to initialization parameters through the console

If you have coded PARMERR=INTERACT, and CICS detects a parameter error, either in the keyword or in the value you have assigned to it, CICS prompts you to correct the error with message DFHPA1912 or DFHPA1915:

DFHPA1912 'applid' SIT OVERRIDE 'keyword' IS NOT RECOGNIZED.
                   SPECIFY CORRECT SIT OVERRIDE.
DFHPA1915 'applid' INVALID DATA HAS BEEN DETECTED FOR SIT OVERRIDE 'keyword'.
                   RESPECIFY THE OVERRIDE.

CICS prompts you to enter corrections to any errors it finds in the PARM parameter or the SYSIN data set after it has loaded the SIT, and as each error is detected. This means that if there is an APPLID parameter following the parameter that is in error, either in the PARM parameter or in the SYSIN data set, it is the APPLID coded in the SIT that CICS displays in messages DFHPA1912 and DFHPA1915.

Related tasks
Specifying CICS system initialization parameters
Supplying system initialization parameters to CICS
Controlling start and restart
Related reference
The system initialization parameter descriptions
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