Patent ID: 7600177
Filing Date: 2009-10-06
Classification: G11B,H03M

Abstract:
1. A method to correct a first block of first data, comprising the steps of: (A) calculating a plurality of first row syndromes from said first block arranged as a Reed-Solomon product code; (B) calculating row error correction information by decoding said first row syndromes; (C) applying said row error correction information to said first data as stored in a first buffer, wherein said first buffer holds at most a first fraction of said first block; (D) calculating an initial set of values of a plurality of first column syndromes from said first block as read from said first buffer after said row error correction information has been applied; (E) storing both said first row syndromes and said first column syndromes in a local memory, wherein said first data is excluded from said local memory; (F) decoding in a sequence alternating between a first pass and a second pass, wherein (i) said first pass comprises decoding using only said first column syndromes to generate column correction results and (ii) said second pass comprises decoding using only said first row syndromes to generate row correction results; (G) updating (i) said first row syndromes in response to said column correction results and (ii) said first column syndromes in response to said row correction results; (H) generating both a plurality of row corrections and a plurality of column corrections in response to said first row syndromes and said first column syndromes; (I) generating corrected data by correcting said first data as stored in a second buffer using both said row corrections and said column corrections, wherein said first data as written into said first buffer after said row error correction information has been applied matches said first data as written into said second buffer after generation of all of said row corrections and said column corrections; and (J) generating an output signal carrying said corrected data.