Running VTAM Buffer Traces

In certain cases, TIBCO technical support might request that you collect a buffer trace to assist them in debugging communication problems.

Use the following command to instruct VTAM to start tracing all activities that are occurring with a particular LU.

F vtam,TRACE,TYPE=BUF,ID=luname

Where, vtam is the name of the VTAM started task on the system that is running the platform server, and luname is the name of the LU for which you want to collect trace information.

To start collecting trace information, run the generalized tracing facility (GTF). The following sample PROC can be used to start the generalized trace facility: 

//GTF  PROC               
//******************************************************************* 
//* GTFTP                                                           * 
//* THIS IS THE STANDARD TRACE PROC FOR TRACING THINGS IN VTAM.     * 
//* THE SYSIN FILE IS LOCATED IN USER.PARMLIB(GTFTP)                * 
//*        ---------------------------------------------------------* 
//******************************************************************* 
//IEFPROC EXEC PGM=AHLGTF,PARM='MODE=EXT,DEBUG=NO,TIME=YES',       -
// TIME=1440,REGION=4000K            
//IEFRDER DD DISP=SHR,DSN=SYS1.TRACE         
//SYSLIB  DD DISP=SHR,DSNAME=USER.PARMLIB(GTFTP)
//*-----------END OF PROC "GTF"-------------------------------------*

The following SYSIN file is associated with the GTF PROC:

TRACE=RNIO,USR

After you have reproduced the problem that you are trying to debug, you must perform the following tasks:
  • Stop the VTAM buffer trace using the following command:

    F vtam,NOTRACE,TYPE=BUF,ID=luname

  • Stop GTF using the conventional IBM stop command from a console or SDSF.

After GTF has stopped collecting the trace information, you must format the information that GTF has collected. The following sample PROC can be used to format the buffer trace: 

//TAPBUF PROC OUTC=X,D=LOCAL           
//*--------------------------------------------------------*   
//*-THIS PROCEDURE INVOKES THE TRACE ANALYSIS PROGRAM -----*   
//*-IN ORDER TO PRINT A PREVIOUSLY TAKEN VTAM BUFFER-------*   
//*-TRACE THAT IS HELD IN THE DATA SET "SYS1.TRACE"--------*   
//*--------------------------------------------------------*   
//TAPSTEP EXEC PGM=ACFTAP,REGION=3000K,PARM='READ'      
//SYSTRACE DD DISP=SHR,DSN=SYS1.TRACE         
//STEPLIB  DD DISP=SHR,DSN=NCP6.SSPLIB         
//SYSIN    DD DISP=SHR,DSN=USER.PARMLIB(TAPBUF) 
//SORTIN   DD DISP=(NEW,DELETE),DSN=&&SORTIN,SPACE=(CYL,(13,5)), 
// DCB=(RECFM=F,LRECL=364,BLKSIZE=364),UNIT=SYSDA    
//SORTOUT  DD DISP=(NEW,DELETE),DSN=&&SORTOUT,SPACE=(CYL,(13,5)), 
// DCB=(RECFM=F,LRECL=364,BLKSIZE=364),UNIT=SYSDA    
//SYSPRINT DD SYSOUT=&OUTC,DEST=&D        
//SYSSDPRT DD SYSOUT=&OUTC,DEST=&D,FREE=CLOSE,SPIN=UNALLOC  
//SYSSSPRT DD SYSOUT=&OUTC,DEST=&D        
//SYSGSPRT DD SYSOUT=&OUTC,DEST=&D        
//SYSDTPRT DD SYSOUT=&OUTC,DEST=&D        
//SYSNEPRT DD SYSOUT=&OUTC,DEST=&D        
//SYSCAPRT DD SYSOUT=&OUTC,DEST=&D        
//SYSCSPRT DD SYSOUT=&OUTC,DEST=&D        
//SYSTEMP1 DD DUMMY   FOR ETHERNET DATA     
//SYSTEMP2 DD DUMMY   FOR ETHERNET DATA     
//*-----------END OF PROC "TAPBUF"-------------------------*

The following example shows the SYSIN file associated with the TAPBUF PROC: 

INPUT=BUFFER, 
SOURCE=GTF, 
LONGPIU=YES, 
SUMMARY=NO, 
LSPRT=NO, 
LDPRT=NO, 
SDPRT=YES, 
SSPRT=YES, 
DTPRT=YES, 
NEPRT=YES, 
GSPRT=YES, 
VTPRT=NO, 
IXPRT=NO, 
NPPRT=NO, 
NTPRT=NO, 
LUPRT=NO, 
GO  
QUIT
Note: LONGPIU=YES is only supported by VTAM version 4 or higher. This parameter instructs VTAM to print the entire request unit instead of the default that is to print only the first 252 bytes. If you are running VTAM version 4 or higher, ensure that this parameter is set to YES.

You can get several different formats from running this sample TAPBUF PROC. The information that you send to TIBCO technical support is the output generated with the DD statement SYSSDPRT.