Method and apparatus for encoding magnetic disk sector addresses

摘要

The invention encodes magnetic disk sector addresses using a large distance, "d", Reed-Solomon code to produce code words which vary by at least "d" symbols for any two different encoded addresss. The result of the encoding is a set of redundancy symbols, which are usually associated with error correction. These symbols are appended to the address symbols to produce address code words. An address code word read from a disk can contain up to (d-1)/2 errors and still be identified as the correct sector address. To protect the encoded sector address from synchronization errors the address code words are further encoded by adding them to a coset leader to produce header code words. The header code words are then recorded in the address portions of the sectors. When a header code word is read from a sector, the coset leader is subtracted from the header code word to produce an address code word. The address code word is then compared with the address code word for the specified address. If there is a synchronization error, the comparison of the resulting address code word with the address code word for the specified address will result in a difference of more than (d-1)/2 symbols and the sector will not be treated as the specified address.