JPH06162521A - Method for correcting seek stroke of magneto-optical disk - Google Patents

Abstract

PURPOSE:To allow access to a target track in one seek without reseeking and to shorten seeking time by detecting the address boundary of cross-cutting track and correcting the number of seek strokes. CONSTITUTION:In the case of a seek method in which the number of cross-cutting tracks is counted and positioning to a target track is made, an INDEX pulse is outputted so as to be outputted at the address boundary of the cross-cutting track CVRSCT #0, and the number of the seek strokes is corrected through the number of times of the generation during the seek operation. Then, the crossing of a track which is generated by rotation is detected by the crossing pulse 18 of rotating track, which is transmitted to a circuit 27 for changing counter value of a seek completion, the counter value of the seek completion is changed and transmitted to a circuit 26 for detecting the seek completion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seek method for an apparatus using a disk in which a track is spirally carved, and in particular, in the case of seeking by counting the number of transverse tracks, whether the transverse tracks generated by rotation are detected or not. Or correct the seek stroke depending on whether to predict in advance,
To reduce seek time.

[0002]

2. Description of the Related Art FIG. 6 shows the relationship between the number of traversing tracks and reaching tracks. FIG. 6 shows the disc as a continuous continuous plane in the circumferential direction. Also, in this figure, the spiral is in the outer peripheral direction. For example, if the seek speed is 15 ms / track (the following track is Tr) (1), Tr # 0 →
When the seek of Tr # 3 is performed across three tracks (hereinafter referred to as cross track), Tr # 6 is reached. In (2), when Tr # 3 → Tr # 0 seek is performed for 3 cross tracks, Tr # 3 is reached. That is,
In the case of the outer peripheral spiral, the arriving tracks are displaced outward by the same number as the disk rotation number during the cross track operation. Similarly, in the case of an inner circumference spiral, it shifts to the inner circumference. Therefore, the correction increase / decrease for the seek direction and the spiral direction is as shown in Table 1.

Conventionally, when an error has occurred in a track that has arrived without correction, the track address is monitored again and re-seek is performed. This causes a problem that seek time is extended.

Japanese Patent Laid-Open No. 3-12033, which is the same as that of correcting a seek stroke, which is not intended to correct the inevitable track error which is inevitably generated in the method of counting the number of transverse tracks and seeking. .

[0005]

[Table 1]

[0006]

In the method of counting the number of tracks crossed and seeking, there is a problem that the track addresses landed by the same number as the track address boundaries crossed during the seek are displaced in the spiral direction. A seek stroke correction method capable of reaching a target track with a single seek even if a deviation occurs. The seek stroke is corrected by detecting the crossing track address boundary and increasing or decreasing the number of seek strokes. Alternatively, the seek stroke is corrected by predicting the number of tracks that will be traversed in advance and increasing or decreasing the number of seek strokes with respect to the number of tracks to be moved.

[0007]

According to an embodiment of the present invention, a horizontal crossing track address boundary is output at the horizontal crossing track address boundary CVRSCT # 0 by using an INDEX pulse generated once for one rotation of the disk. The INDEX pulse is modified to increase or decrease the number of seek strokes depending on the number of occurrences during seek execution.

In another embodiment of the present invention, the number of seek strokes to be traversed is predicted in advance. Therefore, the number of seek strokes to be moved and the seek start sector position are used to determine the number of seek strokes. Increase or decrease.

[0009]

[Function] In the case of the seek method in which the track is a spirally engraved disk and the number of traversing tracks is counted and positioned on the target track, the traversing track address boundary caused by the rotation is detected and corrected or crossed in advance. There are two methods of knowing the number of track address boundaries and correcting the seek stroke number. The former is a crossing track address boundary CVRSCT #
The INDEX pulse is output so that it is output at 0, and the seek stroke number is corrected by the number of occurrences during the seek execution. The latter uses the seek stroke correction table to correct the seek stroke number from the seek number to be moved and the seek start sector position.

[0010]

EXAMPLES An example of the present invention will be described below.
Processing and tracking until the seek operation becomes possible will be described with reference to FIG. The optical disk 1 transmits a spindle drive instruction signal 16 to the spindle drive circuit 10, and the spindle motor 2 is thereby started up to a steady rotation. The light beam emitted from the laser 9 reaches the optical disc 1 through the optical system. As the optical disc rotates, the information track is finely swayed vertically and horizontally. In order to accurately position the light beam on the information track, the objective lens 49 is moved up and down by the autofocus actuator 4 to narrow down the light beam. For tracking, as a coarse positioning system, the tracking servo signal 39 is driven through the optical head control circuit 8 to drive the voice coil motor 6 to move the entire optical head 3. As a fine positioning system, the tracking servo signal 39 is controlled by the tracking control circuit 7 to control the galvano mirror 5. The autofocus system is not directly related to the present invention and will not be described.

Next, the seek operation (seek stroke correction method by hardware of plan 1) will be described with reference to FIGS. 1 and 2. However, the spiral direction will be described below as the outer peripheral direction. The target track address is designated by the upper multiplication device 62 and transmitted to the microprocessor 60. The read signal 50 passes through the reproduction circuit 51 and outputs IDVALJD54 (FIG. 2- (i)) indicating that the ID is valid.
RVR, SCTID detection circuit 52, CVRSC T (current sector) 53, CVRTR (current track)
55 (FIG. 2- (l)) is transmitted to the microprocessor 60. Thus, the number of tracks to be moved is calculated, and the number of tracks 30 (added by the seek end counter value in order to prevent the subtraction counter 24 from becoming negative) and the seek end counter initial value 31 are set in the track number setting circuit 25. Set the seek direction 35 (FIG. 2- (a)) to the outer peripheral side and set the seek end counter value increase / decrease instruction 32 (determined by the seek direction spiral direction) to subtract,
The head starts moving by setting the speed control servo drive instruction signal 36 (FIG. 2- (b)). At this time, the tracking servo instruction signal 37 (FIG. 2- (c)) is reset by the signal 36 passing through the inverter 63 and the OR circuit 64. As the head moves, the tracking servo signal 39 (FIG. 2- (e)) passes through the linearization circuit 20 to generate a linearization signal 40 (FIG. 2- (f)), which is transmitted to the cross track detection circuit 21 and is tracked. A cross track pulse 28 is generated to indicate that the cross track is crossed. The number given by the track number setting circuit 25 is set to the cross track pulse 28
The number of remaining tracks is decremented by the subtraction counter 24 every time when the occurrence of the error occurs and is transmitted to the seek end determination circuit 26 (FIG. 2- (k)) through the remaining track number detection circuit 23. The seek end determining circuit 26 has a seek end counter initial value of 3
1 has already been set. Remaining track number detection circuit 23
Is also connected to the seek speed table 45, and the reference speed 46 (FIG. 2- (d)) corresponding to the number of remaining tracks is transmitted to the adder 65 through the D / A converter 47. The seek speed table is set by the microprocessor 60 immediately after the power is turned on.

The track crossing caused by the rotation is detected by the rotating track crossing pulse 18 (a method of generating this signal will be described later), and this is transmitted to the seek end counter value changing circuit 27 to set the seek end counter value. This is changed and the seek end determination circuit 26 is notified. In FIG. 2, the counter initial value x of the seek end determination circuit 26 decreases each time the rotating track crossing pulse 18 is generated. When the seek end determination circuit 26 determines that the seek has ended, a seek end signal 33 (FIG. 2- (g)) is generated and transmitted to the microprocessor 60. The seek end signal 33 (FIG. 2- (g)) for resetting the signal 60 is also transmitted to the tracking servo ON instruction circuit 25, and OR
The tracking servo instruction signal 37 is set through the circuit 64. To determine if the light beam has followed the track. The tracking servo signal 39 passes through the tracking pull-in determination circuit 22, and the trag pull-in OK signal 38.
(Fig. 2- (h)) is transmitted to the microprocessor 60, and
The signal of 8 monitors whether the light beam has followed the track. If the microprocessor 60 determines that it has followed the track, it monitors the IDVALiD 54. IDV
If ALiD is set, CVRTR (current track) is monitored to determine whether the target track has been reached.

A method of generating the rotary track crossing pulse 18 will be described with reference to FIG. After the spindle drive instruction signal 16 (Fig. 4- (Q) is driven, the spindle is driven, and then the tacho pulse 11 (Fig. 4- (R)) is generated. IN
The INDEX pulse 1 is transmitted to the DEX pulse generation circuit 13.
7 (FIG. 4- (S)) is generated. The microprocessor 60 monitors the INDEX pulse 17 and detects CVRSC Tx53 (FIG. 4) at the time when the INDEX pulse 17 is detected.
(T)) is detected and stored. Next 60 is CVRSC T #
At 0, the DLY time data 14 is transmitted to the DLY circuit 15 so that the INDEX pulse is output, and the rotation track crossing pulse 18 is generated.

A seek stroke correction method based on the table reference method of plan 2 will be described.

FIG. 3 shows the relationship between the number of moving tracks and the seek time. As shown in the figure, due to the acceleration / deceleration and the steady speed variation, the slope becomes like the one-dot chain line. In Plan 1, which has been described so far, the influence of the inclination is not exerted, but in Plan 2, it is affected.

However, when this variation is small, it seems to be effective. Further, it is possible to realize with a simple configuration without the need for adding a circuit. (12, 13, 15, 2
The 7, 25 circuits are unnecessary. ) Microprocessor 6
0 calculates the number of lines to move, and CVRSC T53 (Fig. 2
-(L)) is monitored and a seek stroke correction table (Table 2, timing (Fig. 2- (p)) is used to correct the number of track movements and the number of movements from the seek start sector position to start seek. In the example shown in the table, the table is created by dividing the number of track movements by Tr ₁ , Tr ₂ , Tr _3, ...
The seek start sector position divides one track into two. FIG. 5 shows the relationship between the number of tracks and the track crossing position. A curve when the seek start sector position is “0”, a B curve when the seek start sector position is “2 / m”,
The curve becomes C when the seek start sector position is m. That is, the curve between A and B is approximated by the curve of and the curve between BC is approximated by the curve of. By this, the seek stroke can be corrected, but in order to increase the probability further, the division of the number of seek movements is increased by 1/2 rotation, 1/3 rotation, ... And the division number of the seek start sector position is increased by a few. It becomes possible to make a correction with a higher probability by increasing the numbers such as, 4, ...

[0017]

[Table 2]

[0018]

According to the present invention, the target track can be reached with one seek without re-seek by detecting the crossing track address boundary and correcting the seek stroke number.

Further, by the correction table reference method, the target track can be reached by one seek without re-seek with a simple structure without adding a circuit.

[Brief description of drawings]

FIG. 1 is a seek control block diagram.

FIG. 2 is a seek timing chart.

FIG. 3 is a relationship diagram between the number of moving tracks and seek time.

FIG. 4 is an INDEX pulse generation timing chart.

FIG. 5 is a diagram showing the relationship between the number of tracks and the position of crossing tracks.

FIG. 6 is a relationship diagram between the number of crossing tracks and a reaching track.

[Explanation of symbols]

 18 ... Rotating track crossing pulse, 25 ... Track number setting circuit, 30 ... Track number, 31 ... Seek end counter initial value, 32 ... Seek end counter increase / decrease instruction, 35 ... Seek direction, 36 ... Speed control servo drive instruction signal, 39 ... tracking servo signal, 26 ... seek end determination circuit.

Claims (5)

[Claims] 1. A seek stroke correction method for a magneto-optical disk, characterized in that, in an apparatus using a disk in which tracks are spirally carved, the number of transverse tracks is counted and positioned to a target track. 2. A seek stroke correction method for a magneto-optical disk according to claim 1, further comprising means for detecting a crossing track address boundary caused by rotation. 3. A seek stroke correction method for a magneto-optical disk according to claim 2, further comprising means for correcting a seek stroke after detecting a track address boundary. 4. The seek stroke correction method for a magneto-optical disk according to claim 1, further comprising means for predicting beforehand the number of times a transverse track address boundary generated by rotation is generated. 5. A seek stroke correction method for a magneto-optical disk according to claim 4, further comprising means for correcting a seek stroke.