gtpp2m0c | Programming Standards |
Control programs and real-time programs can execute the SERRC macro or the SNAPC macro to issue a system error. However, use the SERRC macro with discretion because of its high system overhead. With the size of main storage increasing, criteria for issuing system errors has become more rigorous. The SNAPC macro produces more manageable dumps without the overhead required by SERRC.
If a problem can be adequately signalled without a dump, do not take a dump. If a smaller, "snapshot" of memory is enough, it should be taken in preference to a complete dump. The SNAPC macro is preferred for such a snapshot. If the SERRC macro is used, the SLIST parameter lets you define (and restrict) storage lists to be dumped.
Note: During SERRC macro execution, the CPU becomes dedicated to dumping areas of main storage to the real-time logging/activity tape. The dump time is measured in seconds, and during this time the CPU cannot do productive work. This is not true for a SNAPC dump.
The SERRC macro also creates an entry control block (ECB) to send a system error message to the computer operator, and an ECB to carry out a keypoint update.
The following system error numbers are reserved: