The system log

The system log (SYSLOG) is a direct access data set that stores messages and commands. It resides in the primary job entry subsystem’s spool space. It can be used by application and system programmers (through the WTL macro) to record communications about programs and system functions. You can use the LOG command to add an entry to the system log.

Several kinds of information can appear in the system log:
  • Job time, step time, and data from the JOB and EXEC statements of completed jobs entered by user-written routines
  • Operating data entered by programs using a write to log (WTL) macro instruction
  • Descriptions of unusual events that you enter using the LOG command
  • The hardcopy message set

When MVS™ has JES3 as its job entry subsystem, the system log can record console activity. If used to record console activity, the system log is referred to in JES3 messages as DLOG.

In CONSOLxx, you can use the HCFORMAT keyword on the HARDCOPY statement to specify whether hardcopy records should have a 2-digit or 4-digit year.

The system log is queued for printing when the number of messages recorded reaches a threshold specified at system initialization. You can force the system log data set to be queued for printing before the threshold is reached by issuing the WRITELOG command.

If the system log is defined as the only hardcopy medium and SYSLOG fails, hardcopy is suspended and the system issues message CNZ4201E. To avoid the loss of hardcopy, IBM® recommends both SYSLOG and OPERLOG be defined as hardcopy.