JPS5823307A - Assigning method of alternative storage area for rotating type magnetic storage device - Google Patents

Abstract

PURPOSE:To decrease the accessing and to improve the efficiency of use in recording media, by assigning an alternative sector to defective sectors depending on the number of defective sectors on one track or the alternative sectors to all the sectors. CONSTITUTION:A track sector information bit consists of defective/nondefective track display bit A, defective/nondefective sector display bit B and an original alternative sector display bit C. In initializing the magnetic plane of a rotating type magnetic storage device, the number of defects existing on one track is checked and if the number of defective sectors exists a specified number or over (a number determined with the real storage efficiency of the rotating type magnetic storge device and the degree of frequency of accessing to an alternative sector on a system), this track is taken as a defective track and the alternative track is assigned. If the number of defective sectors existing on one tack is a specified number or below, the alternative sector is respectively assigned to the defective sector.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alternative storage area allocation method for a rotating magnetic storage device.

In so-called rotating magnetic storage devices such as magnetic disk devices, a method is generally adopted in which an alternative information storage area is allocated when normal information cannot be read or written due to scratches or the like on the magnetic surface.

One of the conventional techniques is called the alternate track system, which divides the original track area into an alternate track area and an alternate track area as shown in the figure, and if there is a defective track among the tracks in the original track area, a trunk that is a substitute for the defective track is substituted. It is allocated to one trunk in the trunk area, and the allocation operation is performed when the magnetic surface of the rotary magnetic storage device is initialized. FIG. 2 is a conceptual diagram of the track shown in FIG. 1 developed on a plane. Each trunk is divided into equal parts in the case of a fixed length recording method, and each trunk is called a sector. Figure 3 shows the sector recording format, and each sector is roughly divided into an ID section containing address information, a DATA section where data is recorded, and an I/O section.
It consists of a GAP that separates the D part and the DATA part. The ID section consists of a track information pit indicating the status of the track, an address pit indicating the address of the track, and a sector address bit. The track information bit is
It consists of a "good/bad track indicator bit" that indicates whether the truck is a good track or a bad track, and an "original/substitute trunk indicator bit" that indicates whether the trunk is an original truck or a substitute track. The address of the track itself is written in the address bit of a track that is an original track and a good track, and the address of an alternative track is written in the address pit of a track that is an original track and a bad track. . Further, in the address pit of a good track and a substitute track, the address of the original track with respect to the substitute track is written. In this method, if there is even one sector in one track where information cannot be read correctly, all sectors in that track are treated as bad sectors, so the ratio of the alternative track area to all tracks becomes large. It becomes uneconomical.

On the other hand, another method of the prior art is called the alternate sector method. Similar to the alternative track method, this method divides the original sector area into an original sector area and an alternative sector area as shown in FIG. If a defective sector is present, a substitute sector for the defective sector is allocated to one sector of the substitute sector area. Figure 5 shows the sector recording format. Each sector is the same as in the alternative track method, but the ID section consists of sector information bits that indicate the status of the sector and address pits that indicate the address of the sector. . The sector information bit indicates whether the sector is a good sector or a bad sector.
The sector consists of a "good/bad sector indicator bit" and an "original/alternative sector indicator bit" which indicates whether the sector is an original sector or an alternative sector. The address of the sector itself is written in the address pit of a sector that is an original sector and a good sector, and the address of an alternative sector is written in the address pit of a sector that is an original sector and a bad sector. . Further, in the address pit of a sector that is a good sector and is an alternative sector, the address of the original sector for the alternative sector is written. In this method, the alternative storage area is allocated in sector units, so the entire sector area of the alternative sector area (
The ratio of the original sector area + alternative sector area is smaller than that of the alternative track method, making it more economical, but if there are many bad sectors in one track,
There is a drawback that when reading and writing information (DATA portion) of multiple sectors continuously, the overhead for accessing an alternative sector is large and the access time becomes long.

As described above, conventional methods for allocating an alternative storage area to a defective storage area include the alternative track method, which allocates the entire track, and the alternative sector method, which allocates each sector.The former has a short access time, but The former has the disadvantage of low storage medium usage efficiency5, while the latter has high storage medium usage efficiency but has the drawback of long access times.

The present invention was devised in view of the above points, and its purpose is to provide an alternative storage area allocation method for a rotating magnetic storage device that provides short access times and high storage medium usage efficiency.

The feature of the present invention is that it has the advantages of the conventional alternative track method and alternative sector method, and also compensates for the disadvantages of both methods. Allocates an alternative sector in the alternative storage area for this bad sector, and if the number of bad sectors is greater than a certain number, allocates an alternative sector in the alternative storage area for all sectors on this trunk. It is that you are.

FIG. 6 shows an example of a sector recording format when using the allocation method according to the present invention, and the fields of each sector are the same as those explained in the prior art, but the 10th section contains the corresponding fields. It consists of track/sector information bits indicating the status of the track and the status of the sector, and address pits indicating the address of the sector. The trunk/sector information focus includes a "good/bad track indicator bit" A that indicates whether the track is a good track or a bad track, a "good/bad sector indicator bit" B that indicates whether the sector is a good sector or a bad sector, and It consists of an "original/alternative sector indication bit" C that indicates whether a sector is an original sector or an alternative sector. The address bit of a sector that is an original track and a good track, or an original sector and a good sector has its own address written in it, and a sector that is an original track and a bad track, and an original sector. The address of an alternative sector is written in the address bit of the sector that is also a defective sector. ! The address of the original sector with respect to the alternative sector is written in the address bits of the sector that is a good track and an alternative track, and the sector that is a good sector and an alternative sector.

In this method, when initializing the magnetic surface of a rotating magnetic storage device, the number of bad sectors existing on one track is checked, and the number of bad sectors is a specified number (this number is determined by the actual storage efficiency of the rotating magnetic storage device). (determined from the frequency of accessing the alternative sector and the degree of influence on the stem.) If the track exists, the track is determined to be a defective track and an alternative track is allocated. Further, if the number of defective sectors existing on one track is less than the specified number, alternative sectors are allocated to each defective sector.

FIG. 7 shows a command processing flowchart when the CPU executes track format writing, and FIG. 8 shows a program flowchart when initializing a track.

The controller in FIG. 7 receives various commands or control instructions from the cPU, controls the magnetic storage medium, and reads and writes data.

The CPU, controller, and magnetic recording medium themselves are conventionally well known, and the overall configuration thereof is also omitted in the drawings of this application.

In Figure 7, from gap writing to ID section writing, ・
. . . The steps up to gap writing represent the sending of commands by the CPU to the controller.

In FIG. 8, the bad sector counter is a counter created on the program, and is created on the CPU0 main memory.

In step 100, the size of the bad sector counter and the allowable bad sector count are compared, and the track is determined to be bad, and a replacement track is allocated (step 101).
), it is determined whether to allocate an alternative sector to the defective sector (step 102).

As described above, according to the present invention, it is possible to reduce the ratio of alternative sector areas and increase the actual memory usage efficiency, and at the same time, when accessing a track in which many bad sectors exist, In order to take the method,
The frequency of accessing the alternative sector is reduced, and the response time (access time) of the device can be shortened.

[Brief explanation of the drawing]

Figures 1 to 5 show conventional examples, Figure 1 is a diagram showing the relationship between the original trunk area and the alternate trunk area on a rotating magnetic storage device, and Figure 2 is a diagram showing the relationship between the original trunk area and the alternate trunk area on the rotating magnetic storage device, and Figure 2 is the rotating magnetic memory in the alternate track system. FIG. 3 shows an example of sector allocation of a storage device.
The figure shows the sector format of the alternative track method.
FIG. 4 is a diagram showing an example of sector allocation in the case of the alternative sector method, and FIG. 5 is a sector format of the alternative sector method. 6 to 8 show embodiments of the present invention, and FIG.
The figure shows an example of a sector format, Figure 7 is a processing flowchart of a command to execute formant writing for one track, and Figure 8 is a program flowchart for initializing (format writing) one track. There is. A...Good/bad track display bit, B...Good/bad sector display bit, C...Original/alternative sector display bit, 100...Bad sector color/ri> Judgment step of allowable bad sector count , 101... Step 7' in which the track is determined to be defective and an alternative track is assigned.
, 102... Step of allocating an alternative sector to the bad sector. Dice 1 Figure 3 Figure 4 Figure 5 Figure 6 Truck
E, 7 Figure 7 Figure 8

Claims (1)

[Claims] 1. In an alternative storage area allocation method of allocating a bad sector or a bad track in the original storage area of a rotating magnetic storage device where the storage area consists of an original storage area and an alternative storage area, the storage area is located on one track. If the number of bad sectors is less than or equal to a predetermined allowable number, an alternative sector is allocated to the alternative storage area for the bad sector on the track, and if it is greater than the allowable number, an alternative storage area is allocated for all sectors on the track. 1. A method for allocating an alternative storage area in a rotating magnetic storage device, characterized in that an alternative track is allocated to a rotating magnetic storage device.