I/O errors

Errors that are related to an I/O request are usually indicated in the status data provided with the I/O interrupt. These errors are:
  • Device not operational on any path
  • Device status errors, such as a unit check
  • Subchannel status errors: interface control check, channel control check, and channel data check
The operating system processing of the interrupt may include:
  • Invoking a driver exit
  • Interfacing with attention routines and volume verification processing
  • Invoking a device-dependent ERP for error recovery
  • Processing an unconditional reserve
  • Redriving the I/O request on a channel path other than the one that generated the interrupt
  • Requesting an operator action by message IOS115A or by restartable wait state X'115'
  • Issuing message IOS050I to inform the operator that a subchannel status error occurred
Parent topic: I/O device errors