Machine check handler (MCH) record

MCH records (Table 1) are recorded on the logrec data set when any of the following machine failures occur:

Central processor
Storage
Storage key
Timer

When a machine failure occurs, the machine check handler (MCH) receives control by way of a machine check interruption for a soft failure (one that was corrected by the hardware retry features: hardware instruction retry (HIR) or error checking and correction (ECC)), or for a hard failure (one that could not be corrected by HIR and ECC).