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Hardware Field Replaceable Unit Isolation

IP.com Disclosure Number: IPCOM000049647D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Adair, JG: AUTHOR [+2]

Abstract

In a multicard microprocessor system, when initial poweron diagnostic software fails to execute to an identifiable point of progress, the failing field-replaceable unit (FRU) cannot be directly determined. The "dead in the water" state causes replacement of many non-failing cards in an effort to find and replace the failing card.

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Hardware Field Replaceable Unit Isolation

In a multicard microprocessor system, when initial poweron diagnostic software fails to execute to an identifiable point of progress, the failing field- replaceable unit (FRU) cannot be directly determined. The "dead in the water" state causes replacement of many non-failing cards in an effort to find and replace the failing card.

This problem is corrected by isolating at power-on all signals external to the processor card that are capable of stopping execution of diagnostics. This is accomplished with minimum processor card hardware comprised simply of gates in the interrupt request line and other such inputs which are to be blocked under diagnostic control. This guarantees that the diagnostics will gain control if there are no processor card failures. Thus, a failure to execute the diagnostics indicates a processor card failure. Assuming that the diagnostics successfully execute for the processor card, the external signals are selectively enabled, one FRU at a time, so that it is possible to identify a failing FRU through the diagnostic sequence.

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