When the system writes a dump, the dump includes the records in the logrec buffer in storage; the buffer records have been either written to the logrec data set or are queued to be written to the logrec data set.
When you begin to diagnose a dump for a system problem, you can use IPCS to view the system records in the logrec recording control buffer.
The logrec recording control buffer is one of the most important areas to be used when analyzing problems in MVS™. This buffer serves as the interim storage location for hardware and software error records that are queued to be written to the logrec data set. The buffer is significant because of the error history it contains. Also, any records in the buffer that have not reached the logrec data set are almost certainly related to the problem you are trying to solve.