Servo address apparatus and positioning methods for read, write and seek

Abstract

Apparatus and methods are provided to prevent writing and reading at an incorrect position and seeking to incorrect position. A servo address is written in a servo burst and loaded into an error correcting code (ECC) generator for generating write positioning ECC check bytes. The write positioning ECC check bytes are written at the end of the written servo address in the servo burst. When customer data is to be written, the written servo address and write positioning ECC check bytes are read and loaded into the ECC generator to determine whether the writing position is correct. Then the servo address or logical block address (LBA) is preloaded into a second error correcting code (ECC) generator and the customer data is written and loaded into the second error correcting code (ECC) generator for generating data and read positioning ECC check bytes. The data and read positioning ECC check bytes are written at the end of the written customer data. When customer data is to be read, the LEA is preloaded into the second error correcting code (ECC) generator and then the written customer data and the data and read positioning ECC check bytes are read and loaded into the second ECC generator to determine whether the reading position is correct. A secondary servo address that includes a portion of the servo address is written in the servo burst. The secondary servo address can be written adjacent to the servo address; in an automatic gain control (AGC) field; or in a fine servo field of the servo burst. The secondary servo address is read to determine a transducer head position. During a write operation, the secondary servo address can be used exclusively or as a redundancy to the main servo address. The secondary servo address can be used instead of the write positioning check bytes.