Browse Prior Art Database

Array Failure Prediction

IP.com Disclosure Number: IPCOM000107927D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

O'Leary, BJ: AUTHOR [+2]

Abstract

This design describes through use of a Service Processor managed occurrence table, and the methodology for referencing the table entries to predict array bit line and word line failures.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 83% of the total text.

Array Failure Prediction

      This design describes through use of a Service Processor
managed occurrence table, and the methodology for referencing the
table entries to predict array bit line and word line failures.

      Generally in past designs (such as Dynamic Cache Line Delete),
the concern has been to identify a single bit failing within a cache
line (128 byte, for example) and to delete the cache line before
multiple errors occur.  This avoids the potential invalidation of the
cache line contents as would occur in a ECC Checking Block Code
(CBC).

      This design describes the additional function which is added in
the hardware and service processor to provide the capability of
predicting when array failures other than single bit may be
occurring.

      Discrete arrays are known to have different failure modes such
as:  single bit, bit line word line and chip kill.  By using an
occurrence table and its inherent failure history captured through
hardware accessibility to physically addressed array failures,
service processor algorithms are used to map entries to array bit
lines or word lines.  When mapping shows multiple occurrences are
present, the full bit line (ex: 64 cache lines) or full word line
(ex: 128 cache lines) is deleted and the discovery of each uniquely
effected cache line is avoided.  Mapping is managed by empirically
determined thresholds (8, for example) before full bit lines or word
lines are deleted.

      In this mann...