Patent ID: 6288861
Filing Date: 2001-09-11
Classification: G11B,H03M

Abstract:
A data recording disk drive that has a recording disk and a transducer that reads information from or writes information to the disk, the disk drive comprising:a disk having a plurality of generally circular tracks, each of the plurality of tracks having a plurality of data sectors for user data and m angularly spaced servo sectors containing transducer positioning servo information, each of the m servo sectors being one of a plurality of p unique servo types, where p is less than m;a motor for rotating the disk;a transducer which reads information in the servo sectors, including information representing the servo types, and reads or writes user data in the data sectors;a servo type identifier for identifying, from the servo type, each of the m servo sectors as being one of the p servo types; anda servo sector number decoder for determining the servo sector number when a pattern of n sequential identified servo types corresponds to one of m unique predetermined patterns representative of m servo sector numbers, wherein each of the m servo sector number patterns of n bits has a sliding distance d to every other of the m servo sector number pattems, where the sliding distance d determines the error correction capability, and wherein the servo sector number decoder includes means for correctly identifying each of the m servo sector number patterns in the presence of up to s errors and up to e erasures in the n sequential identified servo types, and means for detecting up to s+t errors provided that more than s errors have occurred and that 2s+t+e<d.