Browse Prior Art Database

Alternate Subsystem IPL

IP.com Disclosure Number: IPCOM000042800D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Burns, CS: AUTHOR [+4]

Abstract

The function of buffered file adapter (BFA) 10 is to provide a data path between processor system 20 and up to seven device logic components (DLC) 30. A DLC is a minimum function adapter for a disk file or I/O device. The BFA has two 1K-byte buffers 11 and 12, buffer control logic 13 and 14, system interface control 15, and DLC bus control 16. A functional requirement of the system is to load the system processor 20 with code following a power up; this is commonly referred to as an initial program load (IPL). Such code is received from disk files. The processor generates a primitive control signal to instruct a file to transfer specific data to the processor's memory. Upon reception of the code, the processor will deactivate the primitive IPL control signal and begin executing the code just received.

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Alternate Subsystem IPL

The function of buffered file adapter (BFA) 10 is to provide a data path between processor system 20 and up to seven device logic components (DLC) 30. A DLC is a minimum function adapter for a disk file or I/O device. The BFA has two 1K- byte buffers 11 and 12, buffer control logic 13 and 14, system interface control 15, and DLC bus control 16. A functional requirement of the system is to load the system processor 20 with code following a power up; this is commonly referred to as an initial program load (IPL). Such code is received from disk files. The processor generates a primitive control signal to instruct a file to transfer specific data to the processor's memory. Upon reception of the code, the processor will deactivate the primitive IPL control signal and begin executing the code just received. If any unit along the path of transferred code is not functional, the system cannot be brought up from that file. Normally, a system has alternate file which could be brought up if the first choice fails, for example, a disk as the primary IPL file and a diskette as the alternate file. Because of the intervening BFA 10, processor 20 no longer has intimate control of the files 30, and there is no alternate path for the code to be transferred if a problem occurs in the BFA subsystem 10. The solution to the problem is to utilize the two data buffers, one to transfer code from the disk and the other to transfer code from the diskette. This scheme could be expanded to include as many data buffers as there are IPL devices. Following power up, the system will ini...