Degraded Mode of a File Subsystem Processor
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-04
A file subsystem processor (FSP) enhances system performance. However, on rare occasions, this processor will be inoperative. The system is still available when the FSP is inoperative because the disk and diskette will remain running. The present arrangement enables the system to remain operative even when the file subsystem becomes inoperative. The code for the disk and diskette can operate in either the central processing unit (CPU) or the FSP. At system initial program load (IPL) time, the FSP is in the Data Path C mode (see figure). This enables microcode to be brought directly from disk to the CPU. The CPU now runs under this microcode and begins to IPL the system. At the time of FSP IPL, a status check is made to determine if the FSP hardware is functional.