JPH0714316A - Magneto-optical recording method - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a magneto-optical recording method that eliminates the effect of repeated recording on the decrease in recording density, enables use at the limit of recording density at almost the initial performance, and achieves improvement in recording density. To do. [Structure] (1) The type of information to be recorded is divided into plural types according to the recording repetition frequency, and the recording area of the magneto-optical recording medium is divided into plural types according to the recording density.
A magneto-optical recording method characterized in that information of a type having a higher recording repetition frequency is recorded in an area having a lower recording density. (2) The type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and the type of information with a high recording repetition frequency is stored in a sector of the same length as other types of information in the magneto-optical recording medium. The method of magneto-optical recording is characterized by recording at a lower frequency than when recording in a sector. (3) The type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and the information having a high recording repetition frequency is recorded by dividing the information amount for one sector into a plurality of sectors in the magneto-optical recording medium. A magneto-optical recording method characterized by the above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording method.

[0002]

2. Description of the Related Art As a magneto-optical disk, a 5-inch disk and a 3.5-inch disk, both of which have a standard called the first generation, have already been on the market, and are currently twice or three times as large as that. However, it is expected that the demand for larger capacity and higher density recording will be further strengthened, which is twice or three times that of the existing one.

However, since the optical disk is already recorded near the diffraction limit of light, a large improvement in recording density is required at the cost of other characteristics.
As a matter of fact, in order to increase the density, the wavelength of the laser used is shortened, and ZCAV (Zoned Constant Angular Velocity:
In addition to essential improvements such as the Modified Constant Angular Velocity method, it is largely due to the improvement of the quality of the disk and drive (recording / playback pickup) and the increase of the recording density limit due to stabilization.

On the other hand, in a magneto-optical disk, deterioration with time and characteristic deterioration due to repetitive recording are unavoidable. Particularly, in the case of repetitive recording, when recording is performed at the recording density limit as shown in FIG. The reproduction C / N significantly decreases according to the number of recordings. Therefore, when determining the recording density, it is necessary to set the recording density to a value slightly lower than the limit in consideration of such characteristic deterioration. This has been a cause of hindering high capacity and high density recording.

The present invention has been made in view of the above problems of the prior art, and eliminates the influence of the above-described repeated recording on the decrease in recording density, and enables use at the limit of recording density at almost the initial performance. It is an object of the present invention to provide a magneto-optical recording method that achieves an improvement in recording density.

[0006]

To achieve the above object, according to the present invention, the type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and the recording area of the magneto-optical recording medium is recorded. A magneto-optical recording method is provided, which is characterized in that it is divided into a plurality of types according to the density, and information of a type having a higher recording repetition frequency is recorded in an area having a lower recording density. Further, according to the present invention, the type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and the type of information having a high recording repetition frequency has the same length as other types of information in the magneto-optical recording medium. There is provided a magneto-optical recording method characterized by recording at a frequency lower than that in recording in another sector. Furthermore, according to the present invention, the type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and for information having a high recording repetition frequency, the information amount for one sector is distributed to a plurality of sectors in the magneto-optical recording medium. Provided is a magneto-optical recording method, which is characterized by dividing and recording.

[0007]

EXAMPLES The magneto-optical recording method of the present invention will be described in detail below. The first of the magneto-optical recording methods of the present invention (hereinafter referred to as the first method) divides the type of information to be recorded into a plurality of types according to the recording repetition frequency, and the recording area of the magneto-optical disk according to the recording density. It is characterized in that it is divided into a plurality of types and information of a type having a higher recording repetition frequency is recorded in an area having a lower recording density.

FIG. 2 shows the relationship between the reproducing C / N in magneto-optical recording, the recording density and the number of times of repeated recording. From this figure, the required C / N for magneto-optical recording
In order to ensure the above, the recording density can be increased to a when the number of times of repeated recording is only one. However, when the number of times of repeated recording is 10 ³ times, the recording density can be increased to b and the number of times of repeated recording can be increased. When 10 ⁶ times are required, the recording density can only be increased to c. Therefore,
In order to guarantee the number of repeated recordings of 10 ⁶ times or more, conventionally, the recording density must be set to c or less, which has been a cause of hindering the improvement of the recording density.

On the other hand, in general, information to be written on a magneto-optical disk is almost never rewritten once it is written like an application program, but it is rewritten several times like a file created by a user with a word processor. File management information (MS-DOS FAT, UNI)
There are various types, such as an X inode) and a Windows INI file that are rewritten very frequently.

Therefore, in the first method of the present invention, for example,
The recording density shown in FIG. 2a is the one that is almost not rewritten, and the recording density shown in FIG. 2b is the one that is rewritten several times but the rewriting frequency is not so large. Information having different properties is recorded at different recording densities, such as recording at the recording density c. Actually, when formatting a magneto-optical disk, a plurality of types (two or more types) of regions having different recording densities are prepared, and the regions to be recorded are distributed according to the type of information. As described above, some information is written to the magneto-optical disk in a percentage of the data that is hardly rewritten once, and most of the rest is rewritten several times, but the number of rewritings is not so large. Thus, the capacity of rewriting very frequently is small. Therefore, by securing an area in which the number of rewrites is limited as in the present invention, it is possible to increase the recording density in that area according to the limited number of rewrites. It is possible to raise.

When the first method of the present invention is applied to the CAV method, since the recording density is lower on the outer peripheral side of the magneto-optical disk, it is necessary to record information having a higher recording repetition frequency on the outer peripheral side. To do. Although the recording density is limited on the inner circumference side of the magneto-optical disk, the recording density can be increased by reducing the guaranteed number of times of rewriting on the inner circumference side, and the number of sectors per track increases. This makes it possible to increase the storage capacity and average recording density of the entire disc.

When the first method of the present invention is applied to the ZCAV system, the recording density difference in the magneto-optical disk is small, but the recording density is low on the outer peripheral side of each zone, and therefore the recording is repeated. Frequent information is recorded on the outer peripheral side of each zone. In the ZCAV system, the recording density is limited at the innermost circumference of each zone,
As in the case of the CAV method, the storage capacity and average recording density of the entire disc can be increased, though not as much as the CAV method.

In the first method, a magneto-optical disk in which the physical format is not uniform over the entire disk and two or more kinds of recording densities are intentionally prepared may be used.

Next, the second of the magneto-optical recording method of the present invention (hereinafter referred to as the second method) will be described. In the second method, the type of information to be recorded is set to a plurality of types according to the recording repetition frequency. Separately, the type of information having a high recording repetition frequency is characterized by being recorded at a lower frequency than when recorded in another sector in a sector having the same length as information of another type in the magneto-optical disk.

This second method is effective when there is almost no difference in recording density in the disk such as the CLV system.
In the second method, for example, in the case of a disk formatted with 1024 bytes / sector, an information amount smaller than the standard number of bytes, such as 512 bytes / sector, is recorded in one sector at a low recording density. At this time, recording is performed at a low frequency such as half the standard clock frequency. In the CLV method, the guaranteed number of repeated rewrites is naturally set to the maximum possible number to limit the recording density of the entire disc. However, by reducing the guaranteed number of repeated rewrites of the entire disc, the storage capacity The average recording density can be increased. Even if the set guaranteed number of times of rewriting may be exceeded, no problem will occur.

Next, the third method (hereinafter referred to as the third method) of the magneto-optical recording method of the present invention will be described. In the third method, the type of information to be recorded is set to a plurality of types according to the recording repetition frequency. Information having high frequency of division and recording is characterized in that the information amount for one sector is divided into a plurality of sectors in the magneto-optical disk and recorded.

This third method is also effective when there is almost no difference in recording density in the disk such as the CLV system.
In the third method, information is recorded by dividing information for one sector into two sectors or information for two sectors into three sectors. The third method can also achieve the same effect as the second method.

Further, according to the present invention, it is possible to achieve the intended object also by the following magneto-optical recording using a magneto-optical disk. (1) A magneto-optical disk for CLV in which areas having different sector lengths are prepared. In a CLV magneto-optical disk, the sector length (sector length = the length required by one sector, not the number of bytes per sector) is uniform over the entire disk, but is consciously different. Prepare several types of sector length areas. In this case, the same effect as the second method and the third method is obtained,
Since it is possible to record data having a large number of repeated rewritings at an optimum recording density, it is efficient. (2) A magneto-optical disk for ZCAV having a region in which the sector length is obviously longer than the average sector length of other zones. The magneto-optical disk for ZCAV is usually designed so that the difference in sector length within each zone is very small and the average sector length in each zone is substantially the same. Prepare at least one area with a sector clearly longer than the average sector length of the other zones. When the first method is applied to the ZCAV method,
Only the difference in the recording density in the zone can be improved, but in this case, by recording in the dedicated area, particularly, the one having a large number of times of rewriting, the same effect as in the CLV system can be obtained. (3) A magneto-optical disk for CAV in which an area having a small number of sectors per track is prepared. In the CAV magneto-optical disk, the length of the sector is usually long on the outer circumference side, but the number of sectors per track is set on the inner circumference side or at an unspecified position on the disk in consideration of access. Area with less recording density. The first method is effective in the CAV method only by increasing the storage capacity of the entire disk, but if the access speed is taken into consideration, the storage capacity is somewhat sacrificed, but this method may be advantageous. (4) Magneto-optical disk with one sector having a sector longer than other sectors. A sector having a length longer than other sectors is prepared in each track or every several tracks. Similar to the case of using the disk of (3) above, there are cases where the recording density is increased and at the same time it is effective for the access speed.

[0019]

According to the present invention, a magneto-optical recording method which eliminates the influence of the repeated recording on the reduction of the recording density, enables the use at the limit of the recording density at almost the initial performance, and achieves the improvement of the recording density. Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between the number of repeated recordings and a reproduction C / N when recording is performed at a recording density limit.

FIG. 2 is a diagram showing a relationship between a reproduction C / N and a recording density and the number of times of repeated recording.

Claims (3)

[Claims] 1. The type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and the recording area of the magneto-optical recording medium is divided into a plurality of types according to the recording density.
A magneto-optical recording method characterized in that information of a type having a higher recording repetition frequency is recorded in an area having a lower recording density. 2. The type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and the type of information having a high recording repetition frequency is stored in a sector having the same length as other types of information in the magneto-optical recording medium. A magneto-optical recording method characterized by recording at a lower frequency than when recording in another sector. 3. The type of information to be recorded is divided into a plurality of types according to the recording repetition frequency, and for information having a high recording repetition frequency, the information amount for one sector is divided into a plurality of sectors in the magneto-optical recording medium. A magneto-optical recording method characterized by recording.