A computer system executes instructions for an I/O device not attached to the system. A quasi I/O attachment device is responsive to the commands for the unattached I/O device and generates an interrupt condition. The interrupt condition causes the command instructions for the unattached I/O device to...http://www.google.co.uk/patents/US3938101?utm_source=gb-gplus-sharePatent US3938101 - Computer system with post execution I/O emulation
