Apparatus and method for accessing a disk containing an alternate sector

#This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-106638, filed Apr. 9, 2002, the entire contents of which are incorporated herein by reference.

#1. Field of the Invention

#The present invention relates to a disk storage apparatus in which an arbitrary sector in an alternate area on a disk is allocated as an alternate sector for a defective sector on the disk. Particularly, it relates to an apparatus and method for accessing a disk containing an alternate sector, which enable high speed disk access even if the disk access range designated in a read/write request from a host contains a defective sector, making it necessary to access an alternate sector allocated to the defective sector.

#The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

#FIG. 1 is a block diagram illustrating the configuration of a hard disk drive according to an embodiment of the invention;

#FIG. 2A is a view illustrating an example of a data structure of the defective sector address table 254 appearing in FIG. 1;

#A hard disk drive for recording and reproducing audiovisual (AV) data, according to an embodiment of the invention, will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram illustrating the configuration of the hard disk drive. In the hard disk drive (hereinafter referred to as an “HDD”) shown in FIG. 1, a disk (magnetic disk) 11 as a recording medium has two, i.e., upper and lower, surfaces. One or both of the two surfaces of the disk 11 are used as recording surfaces on which data is magnetically recorded. A head (magnetic head) 12 is provided for each recording surface of the disk 11. The head 12 floats above the disk 11 in accordance with the rotation of the disk 11 when the HDD operates. The head 12 is used to write data to the disk 11 (data recording) and to read data from the disk 11 (data reproduction). Although the HDD shown in FIG. 1 is assumed to have a single disk 11, it may have a plurality of stacked disks 11.

#Each recording surface of the disk 11 has a user area 11a, alternate area 11b and management area 11c. The user area 11a is used by a user. The alternate area 11b comprises alternate tracks. Each alternate track comprises sectors used as alternate sectors to be allocated to defective sectors on the disk 11. The management area 11c is used to store information necessary for system management (i.e. system management information). The system management information contains defective sector management information. The defective sector management information indicates the correspondency between each defective sector and a sector (alternate sector) allocated to each defective sector. The defective sector management information contains a pair of addresses assigned to each defective sector and a sector (alternate sector) corresponding thereto. In the example of FIG. 1, the alternate area 11b is an annular area that surrounds the user area 11a. However, the alternate area 11b may be provided inside the user area 11a. Further, two alternate areas, which are provided inside and outside the user area 11a, may be used. In addition, a format of the CDR (Constant Density Recording) type may be employed in the disk 1. In this case, since the user area 11a is divided into a plurality of annular zones, an alternate area may be provided for each zone. The alternate area 11b and management area 11c are used only by the system. In other words, these areas are non-user areas that cannot be recognized by the user. The area formed of the alternate area 11b and management area 11c is called a system area. Alternatively, only the management area 11c may be called a system area.

#The disk 11 is rotated at high speed by a spindle motor (hereinafter referred to as an “SPM”) 13. The head 12 is attached to the tip of an actuator (carriage) 14. The head 12 is radially moved in accordance with the swing operation of the actuator 14. As a result, the head is positioned to a target track. The actuator 14 has a voice coil motor (hereinafter referred to as a “VCM”) 15 serving as a drive source for the actuator 14. Thus, the actuator 14 is driven by the VCM 15. The SPM 13 and VCM 15 are driven by driving currents (SPM current and VCM current) independently supplied from a driver IC (Integrated Circuit) 16. The driver IC 16 is a motor driver in the form of an IC chip, and serves as SPM and VCM drivers. The values (control variables) for determining the driving currents to be supplied from the driver IC 16 to the SPM 13 and VCM 15 are determined by a CPU 17.