Christopher J Dudley

US Patent:

20060195769, Aug 31, 2006

Filed:

Feb 16, 2005

Appl. No.:

11/059734

Inventors:

Martin Hassner - Mountain View CA, US
Christopher Dudley - Oronoco MN, US

Assignee:

Hitachi Global Storage Technologies Netherlands, B.V. - Amsterdam

International Classification:

H03M 13/00

US Classification:

714785000

Abstract:

To perform error detection and correction on a data sector, syndromes are calculated and used to determine error values and error locations. Logarithmic calculations in Galois field need to be performed to determine the error locations using the syndromes. Finite field vectors are represented as “complex” numbers of the form Az+B. An algorithm is performed using the field vectors represented as complex numbers to generate the error locations. The algorithm requires the use of logarithm calculations. The results of the logarithmic calculations are looked up in two (or more) log tables. The log tables store all the possible results of the logarithm calculations. The log tables store significantly less bits than prior art techniques, reducing the amount of storage space required by a factor of 171. Techniques for controlling accesses to the log tables in an efficient manner are also provided.