JPH056248A - System for alternating defective sector - Google Patents

Abstract

PURPOSE:To considerably shorten read/write processing time. CONSTITUTION:By parallelly writing alternate information to data heads 1 and 2 parallelly writing or reading data on the surface of a disk 6, the allocation of an alternate sector is deifned as the two sets of the same alternate information, these two sets of the alternate information are parallelly read by a seek control part 7, and the read alternate information is decoded by encoding/decoding control parts 3 and 4 and transferred to a host device A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defective sector replacement system for a magnetic disk device.

[0002]

2. Description of the Related Art In a conventional defective disk replacement system of a magnetic disk device, when a defective sector exists on a medium surface, a normal replacement sector is used as a substitute for the defective sector. Therefore, the replacement information is the ID of the defective sector.
When a defective sector is accessed, the location of the replacement sector is obtained from the replacement information. Further, in case the replacement information on the defective sector cannot be read, the replacement information is collected and written in the replacement information sector.

[0003]

Although the above-mentioned conventional magnetic disk device has a plurality of heads on a surface other than the same disk surface, it has only one encoding / decoding control unit and can simultaneously perform data There was only one head for reading and writing. Therefore, when the replacement information written in the defective sector on the medium surface cannot be read, the replacement information sector is read to obtain the location of the replacement sector. There was a drawback that it would increase.

[0004]

According to a method of replacing defective sectors of the present invention, allocation of replacement sectors and writing of replacement information are performed in parallel to a plurality of heads that write or read data on a disk surface in parallel. It is characterized in that a plurality of pieces of the same replacement information are obtained by performing the reading, and the plurality of pieces of replacement information are read in parallel.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a magnetic disk device showing an embodiment of the defective sector replacement system of the present invention.

The magnetic disk device of the present embodiment includes a data head 1 and a data head 2 for reading and writing data on a disk plate 1 for storing data, and data encoding / decoding corresponding to the respective data heads 1 and 2. Encoding / decoding control units 3 and 4 for performing encoding, an interface control unit 5 for controlling data exchange with a higher-level device, and a seek control unit 7 for controlling seek operation of the data heads 1 and 2. There is. In this embodiment, the data heads 1 and 2 always perform the seek operation at the same time, and only one data head does not move independently. Further, by having the two encoding / decoding control units 3 and 4, the data heads 1 and 2 can perform not only the data read / write operation independently but also the data read / write operation at the same time. ..

First, a normal data read / write operation will be described. When the interface controller 5 receives an instruction to read data from the specified sector position on the disk plate 6 from the host device, the seek controller 7 is used to seek the data heads 1 and 2 to the cylinder position where the specified sector exists. .. Next, the data heads 1 and 2 simultaneously search for a designated sector and simultaneously read the data from that sector. The data of the data head 1 is encoded / decoded by the encoding / decoding control unit 3, and the data of the data head 2 is encoded / decoded. The data is decrypted by the control unit 4 and transferred to the host device through the interface control unit 5. When writing, the data transfer direction is from the host device side to the disk plate 6
The same except that it changes to the designated sector above.

Next, the operation of allocating alternate sectors will be described. Here, the defective sector is assumed to be on the medium surface on which the data head 1 reads and writes. When the interface control unit 5 receives an alternate sector processing command for a defective sector from the upper device, the interface control unit 5 uses the seek control unit 7 to seek the data heads 1 and 2 to the cylinder position where the defective sector exists. Next, the data head 1 allocates the replacement sector to the defective sector, and the data head 2 allocates the replacement sector to the normal sector corresponding to the defective sector of the data head 1 and writes the replacement information to the defective sector or the corresponding normal sector. .. As described above, in this embodiment, the replacement sector is also allocated to the normal sector of the data head 2 corresponding to the defective sector of the data head 1.

Next, the operation of reading the data of the sector to which the alternate sector is allocated will be described. When the interface controller 5 receives a command to read data from the specified sector position on the disk plate 6 from the host device, the seek controller 7 is used to seek the data heads 1 and 2 to the cylinder position where the specified sector exists. .. Next, the data heads 1 and 2 simultaneously search for the designated sector. Here, even if the sector that the data head 1 is trying to read is a bad sector and data cannot be read, the data head 2 is reading the normal sector, and therefore replacement information can be obtained. Based on this information, the seek controller 7 seeks the data heads 1 and 2 to the cylinder position where the sector to be replaced exists. Next, the data heads 1 and 2 simultaneously search for an alternate sector, read data from the alternate sector at the same time, and the data of the data head 1 is encoded / decoded by the encoding / decoding control unit 3, and the data of the data head 2 is encoded / decoded. The data is decrypted by the encryption control unit 4 and transferred to the host device through the interface control unit 5.

[0010]

As described above, the defective sector replacement method of the present invention allocates replacement sectors and writes replacement information to a plurality of head groups that write or read data on the disk surface in parallel. By performing in parallel, a plurality of pieces of the same replacement information are read, and the plurality of pieces of replacement information are read in parallel. Therefore, there is no case where the replacement information written in the defective sector cannot be read, and the replacement information sector is read. Since it is not necessary to perform the process of obtaining the location of the alternate sector, the read / write processing time can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a magnetic disk drive showing an embodiment of a defective sector replacement system according to the present invention.

[Explanation of symbols]

 1, 2 data heads 3, 4 encoding / decoding control unit 5 interface control unit 6 disk plate 7 seek control unit

Claims (1)

Claim: What is claimed is: 1. A plurality of heads that write or read data on a disk surface in parallel are allocated to a plurality of heads in parallel and replacement information is written in parallel. And a method of replacing a defective sector, wherein the plurality of pieces of replacement information are read in parallel.