GTFPARM (generalized trace facility parameters)

GTFPARM provides default or installation-defined trace options to control the generalized trace facility (GTF). The member is read only when the operator (or an automatic command) issues START GTF. GTFPARM is not used during system initialization.

The member name on the START command can be the same as the IBM-supplied cataloged procedure, GTF. The PROC statement of that procedure identifies GTFPARM as the member from which GTF will get its trace parameters. If the installation wants to place the GTFPARM member in a data set other than SYS1.PARMLIB, specify the alternate data set in the SYSLIB DD statement and then specify a member from that PDS using the MEMBER keyword. If the installation wants to substitute another member in place of GTFPARM, the operator may enter the replacement member name on the START command with the MEMBER keyword.

The IBM® procedure, GTF, as supplied in SYS1.PROCLIB, contains these statements: 
//GTFNEW PROC        MEMBER=GTFPARM
//IEFPROC EXEC       PGM=AHLGTF,PARM='MODE=EXT,DEBUG=NO,
                     TIME=YES',TIME=1440,REGION=2880K
//IEFRDER DD         DSNAME=SYS1.TRACE,UNIT=SYSDA,
//                   SPACE=(TRK,20),DISP=(NEW,KEEP)
//SYSLIB DD          DSN=SYS1.PARMLIB(&MEMBER),DISP=SHR

For further analysis of this procedure and additional information about GTF trace options, see z/OS MVS Diagnosis: Tools and Service Aids or the GTF topics in z/OS MVS Diagnosis: Tools and Service Aids.

Because default options in GTFPARM specify minimal data for only a limited number of traced events, you may wish to tailor GTF to trace specific events for problem determination purposes through one of the following methods:
  • Specify another SYS1.PARMLIB member name, using the MEMBER keyword on the START command.
  • Change the trace options in GTFPARM.
  • Change the SYSLIB DD statement of the IBM procedure to specify a parmlib member that has the options you want.
  • Retain the IBM procedure to handle default options, and write one or more alternate procedures, each specifying a different alternate parmlib member. You could design each member to contain GTF options useful under particular circumstances. Instruct the operator when to issue the START command for each member name.

GTF tries to read parameters from the specified parmlib member. If an error occurs in opening or reading the member, or if GTF detects a syntax error, it writes a diagnostic message to the operator, and requesting that SPECIFY TRACE OPTIONS be used, as if no GTF parmlib member were available. The operator therefore must have a complete list of desired GTF parameters available when he starts GTF.