JPS63302474A - Disk recording medium - Google Patents

Abstract

PURPOSE:To heighten probability in which a sector having no error exists, by arranging sectors of the number that is not an integer on track length equivalent to one revolution of a disk. CONSTITUTION:A sector 11 consisting of an address part 1, a data part 2 which houses control data, and an error detection part 3 is recorded on a spiral track 9 for a large number of times. In such a case, it is constituted so that the sectors 11 of the number that is not the integer can be arranged on the track length equivalent to one revolution of the disk. Therefore, the position of a start point 10 on the sector is deviated at every revolution of the disk, thereby, the position can be observed. In such a way, the probability in which the sector without generating the error exists can be heightened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disk recording medium and a track portion for storing control data therein.

[Conventional technology]

When recording data on a write-once optical disc or an erasable optical disc, the data is usually grouped into sectors and then recorded. FIG. 3 is a block diagram showing an example of the sector configuration, in which an address section (1) indicating the position of the sector is present at the beginning, and a data section (2) consisting of a - group is present at the center. In the case of optical discs, the data error rate is high because the recording density is high. For this purpose, it is used with data to form an error correction code or error detection code. A check bit (3) serving as an error detection section is placed at the end.

On the other hand, although the guide groove of an optical disk is a spiral, in order to simplify track management in an optical disk memory with a constant rotation speed, within one track, that is, 360 degrees (hereinafter referred to as (Described as one lap of the track)
Several sectors are arranged in the .

FIG. 4 is a block diagram showing the structure of sectors of such a conventional disk recording medium. In the figure, (4) is an optical disk recording medium, and (5) is a sector provided on the outer circumferential side of a spiral track. It is a control track section, and the track length (one round of the track) corresponding to the rotation of the disk is 8
A large number of sectors with the same contents are recorded over many rounds in a state where one sector exists.

Since optical disk memory requires the use of various optical disks for recording and playback, conventionally an identification hole has been provided in the diffuser center section to automatically identify control data such as the characteristics and type of the disk. It was getting worse. As an example of this, for example, the Journal of the Television Society (νO
L.

38, No. 3 (1984)) in 8mm video. In this example, only one control data can be conveyed for one identification hole,
When it is desired to transmit a large amount of control data, there is an inconvenience in that a large number of identification holes are required. As an improvement to this method, as shown in Fig. 4, a track section (hereinafter referred to as a control track section) in which a large amount of control data indicating the characteristics and type of the disk is recorded on the innermost and outermost circumferences of the disk. A method is being considered in which a hook portion (5) is provided. The control data is recorded as phase pits so that it can be played back on any type of disc, and the control data is recorded using software (without using special demodulation hardware) using a microcomputer already installed in the optical disc drive. It is desirable to be able to demodulate data using Therefore, it is necessary to reduce the transfer speed as much as possible, and it is desirable that the recording density is low. Furthermore, in order to improve the reliability of the read control data, sectors having the same control data are recorded multiple times over multiple tracks.

Therefore, it is normal to arrange a very small number of sectors with the same content, 2 to 3, in one track.

Here, one embodiment of demodulating data using a microcomputer will be described with reference to the drawings.

FIG. 5 is a block diagram showing the parts related to demodulation of the optical disk device, and FIG. 6 is an output state diagram of each part shown in FIG. 5 during demodulation. The control data recorded on the optical disc is recorded in circular phase pits as shown in signal (b) of FIG. A phase pit consists of a hole of a certain depth on the surface of an optical disk, and information is read out using the property that the intensity of reflected light when irradiated with a laser beam changes depending on the position of the phase pit. A large number of these phase focuses are made in succession, and information is recorded depending on whether there are any phase pits. In this example, 128 consecutive phase focuses,
If the following section has no phase bits with a length of <128 pieces, the information is set to "0", and conversely, when there is a phase focus of 128 pieces after a section with a length of <128 pieces, the information is set to "0". "1'" is recorded.In the signal (b) shown in FIG. 6, the information "0" is recorded as shown in the signal (a).An optical disk recording medium with phase focus ( 4
) The change in the power of the reflected light regenerated by the optical head (1
0), amplified by an amplifier (11), and binarized into "1" and "O" signals by a detector (12). The output from the detector (12) becomes a pulse train as shown in signal (c) of FIG. This pulse train is used in a retriggerable multi-by-break (13) to create a signal (d) that outputs "1" when there is a pulse train, and outputs "O" when there is no pulse train for a certain period of time. This signal (d) is For example, number 10
It changes every 1I11 of μsec. (No. 8 (d) is periodically fetched from the microcomputer (15) into the register (14) every few μsec as shown in the signal (e). This fetched signal (f) is sent to the microcomputer (
15) and demodulates the control data using software to obtain necessary control information. Among the blocks in FIG. 5, the optical head (10), amplifier (11), and detector (12) are blocks necessary for reading normal data, and there is no need to add them specially for reading control data. Further, the microcomputer (15) is essential for configuring the optical disk drive, and is not added specifically for reading control data.

Therefore, the special circuits required to read the control data are the retriggerable multipipe lake (13) and the register (14), and by recording the control data on the optical disk recording medium (4), the optical disk drive can be 'M There's no need to be sloppy. Generally, it is preferable that the control data be written on the optical disk recording medium (4) at a density and read out at a slow speed.

[Problem that the invention seeks to solve]

Since conventional disk recording media have the above-mentioned configuration, in the case of optical disks, the track density is very high compared to magnetic recording, etc., and track correlation of errors is very easy. For this reason, if the data on a track on a certain track is incorrect, there is a high probability that the data recorded in a portion adjacent to the data on the track on the next track will also be incorrect. Therefore, for example, if there are three medium defects (6), (7), and (8) in the control track section (5) as shown in FIG. 4, each sector may be completely affected. Moreover, error correction used for control data,
Since detection codes are often very simple, such defects cannot be corrected. Naturally, if the number of sectors recorded in one round of the track is increased, the probability of this decreases, but in this case, another problem arises: the data transfer rate increases. The present invention is intended to solve these problems, and aims to provide a disk recording medium that has a high probability of having sectors in which no errors occur.

[Means for solving problems]

In the disk recording medium according to the present invention, one sector consisting of an address section, a data section storing control data, and an error detection section is recorded many times on a spiral track, which corresponds to one rotation of the disk. The track length has a non-integer number of sectors.

[For production]

In the disk recording medium of this invention, the positions of the starting points of each sector were aligned in the radial direction of the disk in conventional ones, but in the disk recording medium of this invention, they shift with each rotation of the disk and the positions change. The probability that there will be a sector in which no error occurs increases.

〔Example〕

1M is an explanatory diagram illustrating the sector configuration of a disk recording medium according to an embodiment of the present invention, and shows the case where the number of sectors in one track rotation is 17/7. In the figure, (9) indicates a spiral track, and (lO) indicates the beginning of each sector, ie, the starting point. Further, (11) indicates one sector. The starting point (10) of the sector shifts one by one, and after seven rotations, the phase position of the starting point (10) of the sector returns. (6), (7) are track-correlated defects, their positions include the starting point of the sector, and defects (6), (7) are far apart from each other.

Since these defects (6) and (7) include the starting point of the sector, they generate errors in two sectors before and after the starting point.
Moreover, since it occurs in far away locations, it is recognized that it occurs in the worst location.

However, even if errors occur at such worst positions, there are always sectors without errors. If the above defects (6) and (7) occur in the case where the number of sectors is an integer per revolution of the disk as in the past, the number of sectors per revolution of the track must be 5 sectors or more. It turns out. Compared to 17/7 in the above embodiment, the recording density can be suppressed to about 172, and the transfer speed can also be reduced.

Next, we will find a condition under which there will always be an error-free sector even if the maximum number of track-correlated defects is in the worst position.

First, one round of the track is divided into n parts υ1, for example, into n equal parts, and a condition for the existence of a sector boundary position, that is, a sector starting point (lO) at any boundary position is determined. If the length of one round of the track is T, then the length of the sector is βx T / n... (
1). (However, l and n are positive integers that are relatively prime.) If l and n are not relatively prime, then j! =ax
j! , n=axnl, and the length of n8 sectors is an integral multiple of T.

That is, from equation (1), n, x (axl, xT/axn,) = 1. -T...
(2) becomes. Therefore, the number of phases in which sector boundary positions exist in one round of the track is only n+ types, which is smaller than n.

Figure 2 shows a conceptual diagram of sector boundary positions.

In the figure, the number of errors is D, ~Dl+ is a defect, and A
+ "" A x indicates the starting point of the sector, that is, the leading position. When the defect D1 occurs at the boundary position of the sector, no error occurs in the sector 31 starting from the leading position ZA+ of the sector, avoiding the defect D+.

If a defect D2 is further present at the last position of the sector S, no error occurs in the sector SA starting from the first position A8 of the sector that avoids the defect D2. Sector S
If the defect D3 also exists at the last position of No. 2, no error will occur in the sector S starting from the first position A of the sector that avoids the defect. In this way, no error occurs in the sector S starting from the first position AK of the sector where repeated defects are avoided. Here, if this sector SK satisfies the condition that the first defect D1 does not apply, even if there are any number of defects, the sector SK is always error-free.
k exists.

Expressing this in a formula is as follows.

Rewriting it, -(1+4rixK+l ≦T... (
4) must be satisfied.

Transforming equation (4), we get K −n+(K+) ≦n... (
5), and as n becomes larger, the rotational wait time until the correct sector can be read becomes longer. Furthermore, it is necessary to determine l and n while paying attention to the fact that the recording density increases as It/n decreases. Table 1 shows a distribution example in which there is always a number of error-free sectors even if K=2, that is, there are two defects with track correlation at the worst positions in one track rotation, and a distribution example for K=3 is shown in Table 1. Shown in 2.

Table 1 (K=2) Table 2 (K=3) The number of multiple writes in the table indicates the number of sectors written in one round of the track. In the embodiment shown in FIG.
n=17, 1l=1. = 2, which satisfies the condition shown in equation (5).

In the table, the conditions under which the equality sign holds true in equation (5) are selected, but are not limited to this. for example,
K=2 and n=18. A distribution example of β=7 may also be used. In addition, K in (5) is the maximum allowable number of errors that occur in the worst position; for example, defects that occur in the same sector, or defects that occur adjacent to each other and do not affect the same sector. If such defects are included, the occurrence of K or more errors can be tolerated.

In this way, by determining the length of the sector so as to satisfy Equation (5), it is possible to have a non-integer number of sectors in one round of the track, increasing the probability that there will be a sector in which no error occurs. be able to.

Furthermore, the sector length is not limited to the method described above, and the sector length may be determined using other methods so that the track length includes a non-integer number of sectors.

In addition, although the above embodiment shows control data being recorded at a low density using phase focusing, it goes without saying that other methods such as hole-opening methods or phase change methods may be used and do not depend on the recording/reproducing method. .

[Effects of invention]

As described above, according to the present invention, one sector consisting of an address section, a data section storing control data, and an error detection section is recorded many times on a spiral track in one rotation of the disk. By allowing a non-integer number of sectors to exist in a corresponding track length, it is possible to increase the probability that sectors in which no errors will occur will exist.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams each illustrating the sector configuration of a disk recording medium according to an embodiment of the present invention, FIG. 3 is a configuration diagram showing a general sector configuration, and FIG. FIG. 5 is a block diagram showing a section related to demodulation of a general disk device, and FIG. 6 is an output state diagram of each section shown in FIG. 5 during demodulation. (1) Address section, (2) Data section. (3)...Error detection unit, (4)...Disc recording medium, (9)・l-rank, (11)...
- Sector In the diagram, the same symbol i indicates the same - or equivalent part.

Claims (2)

[Claims] (1) One sector consisting of an address section, a data section that stores control data, and an error detection section,
1. A disk recording medium that is recorded many times on a spiral track and is characterized in that a non-integer number of sectors exists in a track length corresponding to one rotation of the disk. (2) Let the track length equivalent to one rotation of the disk be D,
When the length of the sector is l/n×T, K・l+(K+
1) ≦n (where K is the maximum allowable number of errors that occur at the worst position and is a positive integer, l and n are mutually prime positive integers), and the length of the sector is 1/n×T. 2. The disk recording medium according to claim 1, wherein the track length includes a non-integer number of sectors by determining .