| 摘要 |
Method and apparatus are provided for mapping around defective sectors in a disc drive (12, 25) wherein two outer tracks of the disc in a region beyond the defined track 0 are used to store the drive operating microprogram, and/or manufacturing test program and/or specific mechanical parameters and media defect information. This information can be read from these outer tracks of the disc during initialization of the disc drive, or during seek operations of the drive. It allows the disc drive to react to microprogram problems without changing either a mask ROM or an EPROM. Specifically, the defect list is stored as supplied by the manufacturer on the outer track of the drive. It is merged with the user supplied defect during formatting and used during formatting to flag defective sectors. During initialization of the disc drive, the defect list is loaded into a section of dynamic memory so that it is quickly accessible during seeking of a particular address. Thus, when a seek command is received, the defect list can be accessed, and the positioning command is modified to avoid accessing of a defective block, instead directly accessing the next fully effective block. |
