JPS63288468A - Magnetic disk device using non-volatile memory - Google Patents

Abstract

PURPOSE:To improve the reliability, by accessing a non-volatile memory where information of a track is stored when a computer body accesses the track where a fundamental constant of a magnetic disk is stored. CONSTITUTION:A distributor 5 switches the access object of a computer body I and selects either of a magnetic disk 1 and a non-volatile memory 6. Information stored in track O of a conventional disk 1 is stored in the non-volatile memory 6. In this magnetic disk device II, the distributor 5 switches the access object to the non-volatile memory 6 to read out its contents when the computer body I accesses track O of the magnetic disk 1. Thus, only simple hardware is added to improve the reliability of the magnetic disk without changing hardware and software of the computer body.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a magnetic disk device using nonvolatile memory, and is devised to improve its reliability.

<Prior Art> A magnetic disk device is commonly used as an external storage device for a computer system, and as shown in FIG. 3, a plurality of magnetic disks 1 and a magnetic spatula 1-2 are provided.

A plurality of magnetic disks 1 are fixed to a rotating shaft 3 and rotate as one, and a magnetic disk 2 is installed in a seek machine $44 and moves as one along the radial direction of the magnetic disks 1.

Therefore, as shown in FIG. 4, each magnetic disk 1 has a plurality of concentric tracks T that serve as information storage portions, and the formation positions of the tracks T formed on each magnetic disk 1 are as follows. (distance from the center of the rotating shaft 3) is the same for the upper and lower magnetic disks 1. Each magnetic disk 1
If we connect those with the same track formation position vertically to form a filter surface, it will become a cylindrical surface, which is called a cylinder. On the other hand, if the number is 8, it is possible to specify a single track by determining the cylinder number and head number. Furthermore, each track T is divided into a plurality of areas called sectors, and data is input/output while being allocated to each sector, with the sector as the minimum unit. Note that the operation of writing a unique address into each sector is called formatting.

Data is written and read in units of sectors or blocks, which are one or more consecutive sectors on the same track, depending on the system configuration.

On the other hand, due to variations during manufacturing, the magnetic surface of the magnetic disk 1 has defective portions where data cannot be stored correctly even when written. This defective part cannot be used as a storage part. For this reason, magnetic disk drives do not guarantee normal data input/output for all sectors, but assume that some defective sectors will occur. So Nol～No(n-2)
Let the cylinder be the input/output canister which is a normal storage part,
o (n-1), is used as an alternative area for backing up and storing the defective sectors in the defective parts of the two cylinder input/output cylinders No. Writing sector replacement information. Sector replacement information is information that indicates the correspondence between a bad sector in an input/output canister and a replacement sector in a replacement area, and is a memory table in which a bad sector number and a replacement sector number form a pair and constitute a replacement unit. It is.

That is, in the magnetic disk drive according to the prior art, the format information and alternative information of the No. 1 to last tracks are stored in the 0th track of the magnetic disk 1.

<Problems to be Solved by the Invention> As mentioned above, the 0th track of the magnetic disk 1 stores constants that are the basis of the magnetic disk device.
If this 0th track is damaged, the entire system becomes unusable.

Incidentally, since the 0th track is located at the outermost periphery of the magnetic disk 1, it is easily affected by thermal expansion and is easily damaged by wear.

Furthermore, there is also the problem that if the o-th track is damaged after the magnetic disk is manufactured, it cannot be used as a product.

In view of the problems of the prior art described above, the present invention provides a magnetic disk whose reliability can be improved by devising a means for storing information in a track that stores basic constants, for example, the 0th track of the magnetic disk. The purpose is to provide equipment.

<Means for Solving the Problems> The configuration of the present invention to achieve the above object is to store constants that are the basis of a magnetic disk in a magnetic disk device used as an external storage device for a computer system. Controls M to access the nonvolatile memory that stores track information, the magnetic disk, and the nonvolatile memory from the computer main body, and selects the nonvolatile memory when the track is accessed. It is characterized by having a distributor.

According to the present invention having the above configuration, when the computer main body accesses a track that stores basic constants of a magnetic disk, a nonvolatile memory that stores information on the track is accessed.

Example of implementation Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing a computer system having a magnetic disk device according to this embodiment. In the figure, ■ is the computer main body, and ■ is a magnetic disk device. The magnetic disk device (2) has a magnetic disk 1, a distributor 5, and a nonvolatile memory 6. The distributor 5 switches the pair 9 accessed by the computer main body I, and selects either the magnetic disk 1 or the nonvolatile memory 6. The nonvolatile memory 6 stores information that was previously stored in the 0th track of the magnetic disk 1. This information usually consists of format information, alternative information, and retry count, as shown in FIG. The format information is information about the format from the first cylinder to the last cylinder, the alternative information is a table indicating the location of alternative sectors for bad sectors, and the number of retries is the number of attempts made when access fails. It is something.

In such a magnetic disk device ■, when the computer main body ■ accesses the 0th track of the magnetic disk 1,
The object to be accessed by the distributor 5 is switched to the nonvolatile memory 6. Thus, in this case, the contents of the nonvolatile memory 6 are read out.

<Effects of the Invention> As specifically explained above with the embodiments, according to the present invention, the most important information is stored in a highly reliable non-volatile memory, and a computer can be easily accessed by simply adding simple hardware. Improve the reliability of magnetic disks without changing the hardware or software of the main unit. Further, since it is no longer necessary to guarantee the quality of the 0th shilling in the manufacturing process of the magnetic disk, the yield rate of the product is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a computer system having a magnetic disk device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the connection relationship between the magnetic disk and nonvolatile memory, and FIGS. 3 and 4 FIG. 2 is an explanatory diagram showing a magnetic disk. In the drawing, (2) is a calculation switching main body, (2) is a magnetic disk device, 1 is a magnetic disk, 5 is a distributor, and 6 is a nonvolatile memory.

Claims (1)

[Claims] In a magnetic disk device used as an external storage device in a computer system, there is a non-volatile memory that stores track information that stores basic constants of the magnetic disk, and a magnetic disk and non-volatile memory that are stored from the computer main body. 1. A magnetic disk drive using a nonvolatile memory, comprising: a distributor that controls access to any one of the tracks and selects a nonvolatile memory when the track is accessed.