JPS61202219A - Information recording and reproducing method - Google Patents

Abstract

PURPOSE:To reduce the load of an arithmetic unit and to shorten the access time by specifying a virtual track including a target sector after presuming a track area divided into plural blocks and then correcting the virtual track. CONSTITUTION:An optical disk 1 records and reproduces the information at a fixed linear speed, and a spiral track 2 is formed with a pitch (t). This track 2 is divided into sectors 3 of the prescribed length lS, and a display number (address) is added to each sector 3. Thus it is possible to presume a gathering of blocks of the stepped tracks and proper virtual track and sector numbers are allocated to all sectors. Then a block including the real number of a target sector is decided from said real sector number. When this block is specified, the virtual track number is obtained from the difference between the real sector number and the starting real sector number. An error DELTAT is added to or subtracted from said virtual track number for correction to obtain an actual track number including the target sector.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information recording and reproducing method, and more particularly to an information recording and reproducing method using a disk-shaped medium such as an optical disk and a magnetic disk.

Conventionally, when specifying the position where information should be recorded and reproduced on a disk-shaped recording medium in which information recording and reproduction tracks are set at high density, a complicated calculation method is used, which places a heavy burden on the calculation device. There is a problem that access time becomes long.

Purpose The present invention has been made in view of the above points, and an object of the present invention is to provide an information recording and reproducing method that allows quick and easy access to a position where information is to be recorded and reproduced.

Structure In order to achieve the above object, the present invention provides an information recording and reproducing method that uses a recording medium in which concentric or spiral tracks are divided into sectors of a fixed length, and in which each sector is displayed. A unique code □ is assigned, the track is divided into a plurality of blocks so that the average number of sectors in each track included in each block is an integer, and the target sector to be recorded or reproduced is determined in which block. If it is assumed that each block consists of tracks of the same length, the virtual track that the target sector will be located on is approximately determined, and The radius within the corresponding block for the track! The present invention is characterized in that the true track on which the target sector is located is determined by making a predetermined correction for the increase in track length.

A detailed description will be given below based on one embodiment of the present invention. The 11th ffl is an explanatory diagram showing track 1 to which one embodiment of the method of the present invention is applied. Track 1 in this example is a track of a type in which information is recorded and reproduced at a constant linear velocity, and the pitch is t. A track 2 is formed in a spiral shape, and the track 2 is divided into sectors 3 having a predetermined length fis.

Then, in each sector 3, 0.1, 2, 3.
. . . and an integer display number (address) N is attached.

If the length of one circumference of an arbitrary track 2 is Ωt, then the radius r of that track 2 is.

r=11t/2π. Therefore, the radius r of a track that exactly fits an integer number of sectors on one track is because the length of the sector is Ω3.

r=(sad/2π)n (n = 1.2, 3...
), and such a track exists every time the difference in the radius of the tracks Δr is as follows: Δr=j1g/2π·.

Now, the track radius r is (n g/2g) (n-0,5)≦r<(j1g/2g
)(n+0.5), and if the track pitch is t, the total length of the tracks in this block is L = Qs/2 π・1/l・p, ms . Therefore, within this block, there is a second track, 4. as shown in FIG. average number of sectors,
is n, and a tiger with n sectors, is (
Assume that there are ng/2π・1/l) children.

1: In other words, assuming that n sectors are virtually secured per track, a virtual track number and a virtual sector number can be assigned to all sectors in a similar block, Consider this for all blocks in disk 1. and.

, It is possible to assume a set of stair-stepped rack blocks as shown in FIG. 3, and all sectors of the disk 1 are assigned a unique virtual track number and virtual sector number of 0 or more. As in, there is one track in each block, and the number of sectors to be one changes gradually according to an integer. Assuming a set of blocks on a track, for example, the actual sector numbers (actual sector numbers) are assigned sequentially from the inner circumference.

It is extremely easy to calculate the virtual track number for the track number, ). .

First, based on the given recording cicada and the real sector number Nsj of the target sector to be generated, the block in which this sector is placed is determined. Now, as shown in Figure 4, the average number of sectors is n.
Consider a block, and let the start, real sector number, voice, and track 6 number of the block be N@o and Ijto, respectively. Tough number, Kai Toratu, and Ri number are N respectively.
sa, Nta and QI? , target SEF, ri are included in the block containing the start, real sector number Nso and end 1 work 1゜] Real sector number! JGA determines the quality. Once the block is identified, the real sector number of the target sector is determined.
Real advantage number N 苧 starting from ? Subtract 1, divide the difference by the average number of sectors n? Ta! Add the integer part of to the starting real track number; 1. And 1. A virtual track number N 1tj-, h<' including the target sector is obtained. That is, N'
tj=Nto・.

+I N T ((Npj −Nll0>/n)
-Ca), the actual track number Ntj including the target sector is determined from the virtual track number N'tj obtained in this way, as shown in FIG. The correction may be made by adding or subtracting the difference ΔT to N'tj. The second error formula T can be obtained in advance as follows.

FIG. 5 is a graph showing the relationship between the track number Nt and the number of sectors per track Sn in a block where the average number of sectors is n. In FIG. 5, the starting track in this block (actual track number N to)
track containing the target sector (actual track number Ntj
) is the cumulative number of sectors SL.

becomes. Therefore, the real sector number Nsj of the target sector is N5j=SL+Ns.

It can be obtained with Calculating this, N5j= (Ntj −Nto)”/2 (Nto
-Nta)+ (n-0,5)(Ntj -Nto)
+Ns.

becomes. Here, if we set Ntj-Nto=T, then N5j
= T2/2(Nto −Nte) + (n−0,5
) T+Ns.

It is expressed as Also, using the virtual track number N'tj, N
Expressing sj, N5j = n (N'tj - Nto) + Ns.

becomes. Therefore, T”/2(Nto −Nte) + (n−0,5)
T+Ns.

= n (N'tj - Nto) + Ns.

n (N'tj Nto -T) = T''/2 (Nto -Nte) -0,5T -・=
(β) Here, N'tj -Nto -T = N'tj -Ntj=
-ΔT, T = N'tj -Nto+ΔT, and by substituting this into equation (β) above, a quadratic equation for ΔT is obtained, where ΔT is the virtual track number N″t
It is expressed as a function of j. Therefore, by using the virtual track number N'tj obtained from the above-mentioned equation (α), the corresponding error ΔT can be determined.

The actual track number Ntj of the track containing the target sector is Ntj=N'tj+ΔT, and can be easily determined from the six errors obtained as described above and the virtual track number N'tj. As described above, the track including the target sector to be recorded and reproduced can be specified using a simple calculation method, so that the load on the calculation device can be reduced and the access time can be shortened.

As described in detail above, according to the present invention, after identifying a virtual track containing a target sector assuming a track area divided into a plurality of blocks consisting of tracks of the same length, By correcting this, it is possible to accurately specify the target sector using a simple calculation method. Therefore, it is possible to obtain an information recording and reproducing apparatus at low cost, which reduces the burden on the arithmetic unit and has a short access time. It should be noted that the present invention is not limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an optical disc 1 according to an embodiment of the present invention, and FIGS. 2 to 5 are diagrams showing the operation of each stage of the embodiment of the present invention. (Explanation of symbols) 1: Optical disc 2: Track Ntj: Real track number N'tj: Virtual track number Δ'r: Error

Claims (1)

[Claims] 1. In an information recording/reproducing device using a recording medium formed by dividing concentric or spiral tracks into sectors of a fixed length, each sector is assigned a unique code to indicate the sector, and each sector is assigned a unique code that is included in each block. The track is divided into a plurality of blocks so that the average number of sectors of each track is an integer, and it is determined from the unique code in which block the target sector to be recorded or reproduced is located. , assuming that each block consists of tracks of the same length, approximate the virtual track in which the target sector will be located, and determine that the radius increases in the block corresponding to the virtual track. An information recording and reproducing method characterized in that the true track on which the target sector is located is determined by making a predetermined correction for the increase in track length.