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Diagnostic Programming Using Special Function Register

IP.com Disclosure Number: IPCOM000041257D
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Arlington, DL: AUTHOR [+4]

Abstract

The addition of a Special Function Register to a processor storage card enables direct access to either error correction code and redundant bit arrays or to uncorrected data for more efficient diagnostic storage operations. This technique avoids limited data transfer, slow execution time and reading prior correction bits typically experienced with the usual Processor Bus Operations (PBO). A Special Function Register on the storage card comprises four bits in each of two data flow chips and places the logic in special modes during diagnostic procedures. When performing diagnostics of the checkbit and redundant bit correction arrays, the Special Function Register is set to a value enabling the mode of always transferring data directly into and out of the correction arrays.

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Diagnostic Programming Using Special Function Register

The addition of a Special Function Register to a processor storage card enables direct access to either error correction code and redundant bit arrays or to uncorrected data for more efficient diagnostic storage operations. This technique avoids limited data transfer, slow execution time and reading prior correction bits typically experienced with the usual Processor Bus Operations (PBO). A Special Function Register on the storage card comprises four bits in each of two data flow chips and places the logic in special modes during diagnostic procedures. When performing diagnostics of the checkbit and redundant bit correction arrays, the Special Function Register is set to a value enabling the mode of always transferring data directly into and out of the correction arrays. This maps the arrays into the normal data paths for transfer to and from the processor cards using ordinary storage instructions, such as LOAD and STORE. When there is a cache, the diagnostics are organized to execute storage data transfers in large packets. Since this Special Function makes all stores and fetches involving a main storage card direct transfers to the checkbit and redundant bit arrays, any array failures are exposed by the diagnostics. An informed decision regarding a redundant bit can then be made with shorter execution time. The special function alters the data path so that all sizes of storage operations may be involved to...