Channel With Reporting of Storage Malfunctions Detected on Prefetched Channel-Command Words
Original Publication Date: 1985-Dec-01
Included in the Prior Art Database: 2005-Feb-19
The channel processor provides information that is used to detect storage malfunctions and circumvent these malfunctions without disrupting data processing. Information is provided by means of the subchannel- status word (SCSW) and the extended-status word (ESW). Storage malfunctions can be detected and identified both when they involve prefetched channel-command words (CCWs) or data. The relationship between storage, data transfer, and the channel processor is as follows. The channel processor handles data transfer between storage and an I/O device (for example, a magnetic disk) by executing a program of CCWs. A CCW determines the starting location and the maximum number of bytes in storage to be transferred.