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Transient Data Error Detection for Partial Stores

IP.com Disclosure Number: IPCOM000120145D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Aichelmann Jr, FJ: AUTHOR

Abstract

A method is proposed for providing a way to detect that transient data errors have occurred during partial store operations. This proposal utilizes unused ECC code points as a means to prevent subsequent transient errors from making uncorrectable errors appear as correctable.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 91% of the total text.

Transient Data Error Detection for Partial Stores

      A method is proposed for providing a way to detect that
transient data errors have occurred during partial store operations.
This proposal utilizes unused ECC code points as a means to prevent
subsequent transient errors from making uncorrectable errors appear
as correctable.

      Conventional ECC facilities that detect an error during a
partial store operation abort the store.  This aborted operation
would produce the same error when a retry is executed.  However, if
the environment associated with this application is subject to
transient errors, a subsequent retry could cause an uncorrectable
error to appear as a correctable error.  This would leave the retry
with a data integrity problem.  This proposal forces these partial
store errors into unused single error code points by Exclusive ORing
these errors with a code that converts the uncorrectable error into
unused correctable code points.  If a transient error has occurred,
the uncorrectable error situation will still be detected.  When no
transient errors have occurred the unused code points signal that the
original error was a partial store error.

      Fig. 1 depicts an example of an H matrix that has single error
which produces either 1, 3, or 5 syndromes. Fig. 2 shows a block
diagram of the ECC facility with input and output interfacing.  Fig.
3 shows the valid unused odd code points for the H matrix of Fig. 1.
Fig. 4 shows the block diag...