I/O hardware errors

These errors are caused by hardware malfunctions and are initially processed by control program error routines. If these corrective processes are unsuccessful and the error persists, the control program calls a system error macro, which results in a main storage dump and a message to the system console. Following the WAITC, a transfer is made to the user-specified operational error routine, where corrective action can be started. Because a dump has already been taken by the control program for I/O hardware errors, the operational program should not duplicate this operation by calling another system error.