Steps for diagnosing a system hang

You need to know how to use IPCS and you need access to the following types of information:

Stand-alone dump
EREP report of SYS1.LOGREC
OPERLOG or SYSLOG

The level of z/OS operating system. Use the IPCS CBFORMAT CVT command to find the level of the z/OS.

The following is an example of the CVT output:

********************************************************* TOP OF DATA************************************************************
CVT: 00FD4938

 -0028  PRODN.... SP7.0.6   PRODI.... HBB7709   VERID....                               MDL...... 2064      RELNO.... 038          
+0000  TCBP..... 00000218  0EF00.... 00FF24EC  LINK..... 00FD48B4  AUSCB.... 00FD4F20  BUF...... 00000000  XAPG..... 00FDE310     
+0018  0VL00.... 00FF63DE  PCNVT.... 00FE0CD4  PRLTV.... 00FE0B04  LLCB..... 018E50F0  LLTRM.... 8146E288  XTLER.... 00FE6D10     
+0030  SYSAD.... 00EEA898  BTERM.... 00FEF820  DATE..... 0106114F  MSLT..... 00FD4F48  ZDTAB.... 00DAD000  XITP..... 00FF9740 
+0048  0EF01.... 00FF250C  VSS...... 0000      VPSM..... 0000      EXIT..... 0A03      BRET..... 07FE      SVDCB....

The state of the system. Use IPCS STATUS CPU and note the PSW and mode of each CPU. For example:

CPU(X'00') STATUS:                      
PSW=07060000 00000000 00000000 00000000 
    No work wait                        
  CPU is in no work wait

Typically, a wait state code appears in the program status word (PSW) when the operating system enters a wait state. Use this code and the associated reason code to diagnose and fix the problem. Explanations for wait state codes are found in .

Use the following flowchart to guide diagnosis of a system hang:

Figure 1. Flowchart for system hang analysis

The following steps will guide you through diagnosing a hang or wait.