Browse Prior Art Database

Improved Long Burst Error Correction

IP.com Disclosure Number: IPCOM000122909D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Eggenberger, J: AUTHOR

Abstract

In a block of data covered by an Error-Correcting Code (ECC), long burst errors beyond the correction capability of the ECC can be corrected by use of an appended interleaved parity.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Improved Long Burst Error Correction

      In a block of data covered by an Error-Correcting Code (ECC),
long burst errors beyond the correction capability of the ECC can be
corrected by use of an appended interleaved parity.

      An error in data is detected by the ECC when one or more ECC
syndromes are non-zero.  For a long burst-error that is detected but
not corrected by the ECC algorithm, the non-zero ECC syndrome(s) can
be used in combination with the parity syndrome to correct the burst:
For parity interleaved over C characters, a potential error pattern
of length < C can be defined by searching for the longest string of
zeroes in the parity syndrome and taking the first non-zero character
following that string as the beginning of the pattern, The error
pattern continuing cyclically through the parity syndrome.  The burst
correction process is one of determining the location at which burst
pattern should be applied as a correction.  If the correction is
successful, all ECC syndromes generated from the corrected data will
be all zeroes.  (For purposes of this description, the ECC is
considered to include any additional checks, e.g., CRC, that are
provided for the purpose of protecting against false correction for
uncorrectable errors.

      One method of correcting the burst would be to try all possible
locations for correcting the burst (i.e., starting the error pattern
at every C-th position throughout the block) until a location is
found at which the trial correction causes all ECC syndrome(s) to be
driven to zero.

      A more efficient method is presented here, in which the
trial-and-error method is replaced by computation:

      Having determined P, the pattern of the potential burst
correction, and a non-zero ECC...