JPS61272821A - Magnetic disc controller - Google Patents

Abstract

PURPOSE:To get quickly the address of the substituting destination if a magnetic disc device encounters a substituted sector at accessing the magnetic disc device, by storing preliminarily a substitution table in a storage device. CONSTITUTION:When the address of a sector to be accessed is transferred from a higher device 20, a magnetic disc controller 10 starts accessing a magnetic disc device 30, and the controller 10 retrieves the substitution table if the objective sector cannot be found. When a corresponding alternative address exists as the result of retrieval, a control circuit 15 stores this alternative address in an alternative address storage circuit 14 and returns this alternative address to the high-order device 20 as the response. The device 20 detects it by this response that a part of the area on the magnetic disc 30 which is the object of the requested access is substituted with another sector, and the device 20 accesses the device 30 again.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk control device, and particularly to a magnetic disk control device having an alternative processing function to a hard sector type magnetic disk device.

[Conventional technology]

In conventional magnetic disk control devices and hard sector type magnetic disk devices, when a defective location on a medium is replaced with another good location, the replacement is generally performed sector by sector. The actual replacement process involves the replacement optical address (the address of the sector where the sector is defective and a replacement sector has been allocated) and the replacement destination address (
Address of a sector that is itself a good sector but is allocated as a replacement sector for another bad sector)
A table with pairs of elements as components is written in the magnetic disk device itself, and if a target sector is not found when accessing the magnetic disk device, an alternative destination is determined by looking up the table.

[Problem that the invention seeks to solve]

Since it is necessary to access the magnetic disk each time the table is pulled, there is a drawback that the overall throughput is reduced.

[Means for solving problems]

The magnetic disk control device of the present invention includes an alternative table storage means for storing an alternative table, an alternative table storage means for receiving an alternative table from a host device and storing it in the alternative table storage means, and an alternative table storage means for receiving an alternative table from the host device. access address storage means for storing the access address of the magnetic disk; alternative address transfer means for sending the alternative address obtained by searching the alternative table to the host device; and means for storing the alternative address until it is transferred. and alternative address storage means.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram containing one embodiment of the present invention. The magnetic disk system shown in FIG. 1 is composed of three parts: a magnetic disk controller &10, a host device 20, and a magnetic disk device 30.

In the magnetic disk control device 10, a storage circuit 11 is a circuit for storing an alternative table, an alternative table transfer control circuit 12 is a circuit for receiving an alternative table from a host device 20 and stored in the storage circuit 11, and an address storage circuit 13 is a circuit for storing an alternative table. The alternative address storage circuit 14 is a circuit for storing the access address for accessing the magnetic disk device transferred from the host device 20, and the alternative address storage circuit 14 is a circuit for storing the alternative address to be transferred to the host device 20, and an address control circuit. The circuit 15 is a circuit for searching for an alternative address based on the contents of the storage circuit 11 and transferring it to the host device 20. Further, the alternative table storage unit 31 is a storage part of the alternative table in the magnetic disk device 30.

FIG. 2 is a conceptual diagram showing the format of the alternative table, where the access address is an address specified by the host device 20,
The alternate address is the address of the sector that is substituted for the access address. .

Now, prior to starting normal processing, the host device 20 reads the alternative table from the alternative table storage section 31 of the magnetic disk device 30 and transfers it to the magnetic disk controller 10. In the magnetic disk control device 10 , an alternative table transfer control circuit 12 receives the alternative table transferred from the host device 20 and stores it in the storage circuit 11 .

Next, the operation of the magnetic disk control device 10 in normal processing will be explained.

When an access address indicating the address of the sector to be accessed is transferred from the host device 20, the address control circuit 15 operates and stores this access address in the address storage circuit 13. After this, the magnetic disk controller 10
starts accessing the magnetic disk device based on this access address, but if the target sector is not found during access, it may have been replaced by another sector, so the data has already been stored in the storage device 11. Find an alternative table that is During the search, the address control circuit 15 uses the address of the sector that was not found as a key and searches and determines whether or not an alternative address corresponding to the key exists based on the format of the alternative table shown in FIG. .

If a corresponding alternative address exists as a result of the search, the address control circuit 15 stores this alternative address in the alternative address storage circuit 14, and then returns this alternative address to the host device 20 as a response.

Based on this response, the host device 20 learns that part of the area on the magnetic disk device 30 that is the target of the access it requested from the magnetic disk control device 10 has been replaced with another sector, and It becomes possible to access again based on the alternative address transferred as a response from the control device 10.

On the other hand, if a corresponding alternative address does not exist as a result of the search, the magnetic disk controller [10] responds to the host device 20 as an error.

〔Effect of the invention〕

By storing the substitution table in advance in the storage device, the magnetic disk control device of the present invention can quickly learn the address of the substitution destination when a sector being substituted is encountered during access to the magnetic disk device. There is an effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram including an embodiment of the present invention, and FIG. 2 is a conceptual diagram of an alternative table for explaining the embodiment shown in FIG. 10...Magnetic tisf control device, 11...
...Storage circuit, 12...Alternative table transfer control circuit, 13...Address storage circuit, 14...
... Alternative address storage circuit, 15 ... Address control circuit, 20 ... Host device, 30 ...
. . . Magnetic disk device, 31 . . . Alternative table storage unit. 1. Agent Patent Attorney Uchihara Sound Part F Figure 2 Country

Claims (1)

[Claims] an alternative table storage means for storing an alternative table consisting of a plurality of pairs of access addresses and corresponding alternative addresses; an alternative table storage means for receiving an alternative table from a host device and storing it in the alternative table storage means; an access address storage means for storing the access address of the magnetic disk sent from the device; and a means for searching the alternative table storage means to obtain an alternative address corresponding to the access address and sending this alternative address to the host device. A magnetic disk control device comprising an alternative address transfer means and an alternative address storage means for storing a searched alternative address until it is transferred.