Storage errors

The hardware detects and corrects storage errors where possible. The system is informed of the error by a machine check interrupt. The system invokes recovery routines.

If the storage error is detected during an I/O operation, however, the operation is ended with either a channel data check or a channel control check, depending on whether the error was encountered during data transfer or fetching of the channel control word (CCW) and indirect data address word (IDAW). No machine check interrupt is generated in this case. Error recovery procedures (ERPs) recover from this type of error.