Patent ID: 7827470
Filing Date: 2010-11-02
Classification: G11B,H03M

Abstract:
1. A method of detecting error events in a codeword reproduced by a perpendicular magnetic recording medium (PMR), the method comprising: (a) generating cyclic redundancy check (CRC) parity bits based on a generator polynomial for a source information sequence to be recorded on the PMR and recording a codeword in which the generated CRC parity bits are added to the source information sequence; and (b) reading the recorded codeword and detecting an error event in the read codeword, wherein (a) comprises: (a1) calculating a source information shift polynomial to add the CRC parity bits to the source information sequence; (a2) dividing the source information shift polynomial by a generating polynomial of a CRC code and calculating a remainder of the source information shift polynomial; and (a3) recording the codeword in which the remainder of the source information shift polynomial is added to the source information sequence as the CRC parity bits, wherein in (a2), the generating polynomial used over a wide range of recording densities and different noise environments is expressed as G(x)=x wherein G(x) is the generating polynomial to generate a CRC codeword and x is a parameter indicating a 1-bit delay, and wherein in (a2), when an error event polynomial having an error event as a coefficient is divided by a specific generating polynomial, a specific generating polynomial in which a remainder of the error event polynomial is not 0 is used as the generating polynomial of the CRC code.