Running a GTF Trace for Bus-Tech Devices in an IBM MVS System

To trace I/O activity for a device in an MVS/ESA system, use the GTF PROC, which is a standard IBM PROC in SYS1.PROCLIB used for starting the Generalized Trace Facility. Here is a typical GTF PROC:

 //GTF      PROC  MEMBER=GTFPARM
 //*        LIB:  SYS1.PROC(GTF)
 //*        GDE:  CBIPO MVS INSTALLTION
 //*        DOC:  THIS PROCEDURE EXECUTES THE PTF PROGRAM
 //IEFPROC  EXEC  PGM=AHLGTF,PARM='MODE=EXT,DEBUG=NO,TIME=YES',         X
 //               REGION=2280K,DPRTY=(15,15)
 //IEFRDER  DD   DSNAME=SYS1.TRACE,DISP=SHR
 //SYSLIB   DD   DSNAME=SYS1.PARMLIB(&MEMBER),DISP=SHR

Notice the member GTFPARM in SYS1.PARMLIB. You should code default GTF parameters in that member, so that the desired trace information is captured. Here are the parameters that should be specified in the GTFPARM member to capture the required information:

TRACE=IOP,SSCHP,HSCH,CSCH,CCW

To trace a problem to assist Bus-Tech Customer Support, submit a job to run the GTF PROC. When the job executes, it will require responses at the operator's console. Here are the GTF startup messages and the appropriate responses:

MSG:       *nn AHL125A Respecify options or reply U
RESPONSE:   nn TRACE=IOP,SSCHP,CCWP,HSCH,CSCH
     
MSG:   *nn AHL125A SPECIFY TRACE EVENT KEYWORDS - IO=, SSCH=, IO=SSCH=
RESPONSE:       nn IO=SSCH=A20,CCW=DATA=256
     
            In the example above, we are tracing mainframe device address A20. To trace multiple addresses, reply instead in the format:
     
            nn IO=SSCH=(A20,A21),CCW=DATA=256
     
MSG:       *nn AHL102 CONTINUE TRACE DEFINITION OR REPLY END
RESPONSE:   nn END
     
MSG:       *nn AHL125A Respecify options or reply U
RESPONSE:   nn U

GTF will now be tracing the events on the address(es) you specified. You should now reproduce your problem. After the problem has occurred, stop GTF with the P command at the operators console.

After the GTF PROC has been run to capture the desired trace information, you will need to format the GTF trace data so that it can be sent to Bus-Tech in a readable form. Please remember to format the GTF output, as we are unable to process "raw" unformatted GTF trace output.

The following sample PROC shows an example of how to print the GTF trace:

 //GTFPRT    JOB (A),'USER NAME',MSGLEVEL=(1,1),CLASS=X,MSGCLASS=X 
 //IPCS      EXEC  PGM=IKJEFT01,DYNAMNBR=20,REGION=1500K
 //SYSTSPRT  DD SYSOUT=*
 //TRACE     DD DSN=SYS1.TRACE,DISP=SHR
 //IPCSDDIR  DD DSN=IPOIPCS.DATA.SET.DIRECTRY,DISP=SHR 
 //SYSTSIN   DD *
 IPCS NOPARM
 SETDEF DSN('SYS1.TRACE') LIST NOCONFIRM DDNAME(TRACE)
 GTFTRACE CCW,IO,SSCH
 /*

GTF traces are typically quite large. We would appreciate it if you could direct the GTF print output to a dataset instead of printing it to paper. The dataset can then be downloaded to a PC, it can be compressed using a utility such as PKZIP, and uploaded to our FTP site on the Internet. We would prefer receiving the trace this way, instead of by FAX or regular mail, if at all possible.