JPH05298860A - Method for track-accessing disk - Google Patents

Abstract

PURPOSE:To access disk to a target with high speed by comparing a target block and a present block and adjusting one piece to a count track number of piece in accordance with the large or small and track-jumping a head. CONSTITUTION:First of all, by a track number of piece control part 24, the input signal of track access is received and the track number of piece to the target block is calculated. Then whether the present block is smaller than the target block or not is decided and the number of piece subtracting one piece from the track number of piece is found by a control part 24 when small. Then, by a track jump control part 25, the head is track-jumped to the found track as the jump track to jump within one track of this side of the target track. Further, when it is decided that present block is not smaller than the target block, one piece is added to the track number of piece and similarly, the control part 25 executes track jump operation. Then the head enters within one track of this side of the target track with one jump and track-jump is accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk track access method for accessing a track of a target block on an optical disk or a magneto-optical disk at high speed.

[0002]

2. Description of the Related Art As a current disk track access method, a method is generally used in which the number of tracks from the current block to a target block on the disk is counted, and the track jump is performed by the tracking means by the counted number of tracks. is there.

[0003]

However, in such a conventional track access method, since the number of tracks to the target block is the same as the number of tracks, the track jump is performed, so that the track is within one track before the target block. Therefore, there is a problem that it takes a long time to perform the track jump correction, and therefore the number of track jumps increases by about 1 to 2 times until the access is completed, and the access time is prolonged.

The present invention has been made by paying attention to the conventional problems as described above. By reducing the number of track jumps, a track of a target block can be accessed at a high speed. The purpose is to provide a method.

[0005]

According to a disk track access method of the present invention, a track number calculating step for calculating the number of tracks from a current block to a target block by a calculating means in the track scanning of the disk, and the target block. A block comparison step of determining whether is larger than the current block, and a subtraction step of subtracting one from the number of counting tracks between the blocks when the target block is larger than the current block,
When the target block is smaller than the current block, an adding step of adding one to the number of counting tracks and a track jump by the tracking means by the number of tracks obtained in the adding or subtracting step. is there.

[0006]

In the subtraction step and the addition step of the present invention, one track is subtracted from and added to the calculated number of tracks in accordance with the size of the target block with respect to the current block. Make the track jump to and speed up the track access speed.

[0007]

FIG. 4 is a block diagram showing a schematic structure of a CD-ROM which employs a track search control device for carrying out an embodiment of the present invention. Here, an apparatus having an acoustic digital signal processing section and a CD-ROM digital signal processing section will be described as an example.

A CD-ROM drive circuit (hereinafter referred to as a drive) 1 has a disc holder 3 for holding a disc 2.
A spindle motor 4 for rotationally driving the disc 2, an optical pickup 5 for reading information on the disc 2, an acoustic digital signal processing section 6, and a CD-ROM.
An interface 1 for communicating with a digital signal processing unit 7, a servo control unit 8 for performing focus and tracking control of the optical pickup 5, a system control unit 9 having a microcomputer, and a host computer 10.
1 and mainly.

A plurality of tracks are formed on the disc 2. The spindle motor 4 rotationally drives the disk 2 at a constant linear velocity according to a control signal from the audio digital signal processing unit 6. The optical pickup 5 is the disc 2
It is for irradiating spot light on the disk and receiving the reflected light to read information, and is movable in the radial direction of the disk 2. Further, the optical pickup 5 is provided with an objective lens 27 as shown in FIG. The objective lens 27 is provided for converging the spot light of the optical pickup 5, and is movable in the radial direction of the disc 2 and the contact / separation direction with respect to the disc 2.
By these movements, tracking control and focus control are performed so that the spot light always tracks the track and is converged as spot light having a predetermined diameter. These control units 8 also perform sled servo when moving the optical pickup 5 in the radial direction.

The acoustic digital signal processing unit 6 includes an EFM demodulation unit 12 to which a signal from the optical pickup 3 is input,
A RAM 13 that stores data, an address control unit 14 that controls writing and reading of data to and from the RAM 13, an error correction unit 15 that performs error correction of data using an error correction code (CIRC), and a spindle motor 4
And a speed control unit 16 for controlling the speed of the. The EMF demodulation unit 12 modulates 8-bit data into 14 bits and demodulates the data recorded on the disk 2 into the original 8-bit data. In addition, the speed control unit 16
Outputs a drive signal for controlling the speed of the spindle motor 4 according to the read track information and the like. During normal reproduction, the spindle motor 4 is rotationally controlled so that the linear velocity of the disk 2 becomes constant. At the time of search, acceleration / deceleration control is performed so that the speed of the spindle motor 4 is matched with the rotation speed of the target track. The address control unit 14 also performs an operation (de-interleave) of returning the data interleaved (sorted) and recorded by the data in the RAM 13 to the original order. The output of the error correction unit 10 is output to the outside as an audio signal and is also input to the CD-ROM digital signal processing unit 7.

The CD-ROM digital signal processing section 7 includes
Sync detector 17 and RAM 18 for storing data
A RAM controller 19 for controlling writing and reading of data to and from the RAM 18, ECC (Error Check Code) and EDC (Error Dectec) specific to the CD-ROM.
error correction unit 20 for performing error correction by using a ting code) or the like. The synchronization detection unit 17 detects the synchronization data portion of the data processed by the audio digital signal processing unit 6. Further, in this synchronization detection unit 17,
The scrambling process performed at the time of recording can be released according to the detection result of the synchronization data. RAM
In the control section 19, the header address in the reproduction data is checked by the data stored in the RAM 18.

FIG. 5 is a block diagram showing the functional arrangement of the servo control unit 8 and the system control unit 9. The servo control unit 8 performs tracking control of the objective lens 27, a track servo unit 21 that performs a track jump of the objective lens 27, a focus servo unit 22 that performs focus control of the objective lens 27, and a disc 2 of the optical pickup 5. Sled servo unit 2 for radial servo control
3 and 3.

Further, the system control section 9 causes the track number calculation section 24 and the track servo section 21 to calculate the number of tracks from the information of the track where the optical pickup 5 is currently located and the information of the target track to be moved. A track jump control unit 25 for instructing a track jump and a reading control unit 26 for instructing the optical pickup 5 to read the track information are provided.

Next, the control operation of the drive 1 thus constructed will be described. FIG. 6 is a flowchart showing the general control contents of the system control unit 9. When a power switch (not shown) is turned on, the RAM is displayed in step S1.
Initialization of 13, 18 and initialization such as setting the optical pickup 5 to the initial position are performed. Next, in step S2, it is determined whether or not the disc 2 is mounted on the disc holder 3. After waiting for the disc 2 to be mounted, the process proceeds to step S3. In step S3, the servo control unit 8
To instruct focus search. As a result, the spot light emitted from the optical pickup 5 onto the disc 2 is converged to a predetermined diameter. When this focus search is completed, the process proceeds to step S4, and the servo control unit 8 is instructed to start the focus servo. The focus servo is for moving the objective lens 27 of the optical pickup 5 up and down following the surface deviation of the disk 2.

Next, in step S5, the speed controller 16 is instructed to perform a spindle kick. As a result, a drive signal is given to the spindle motor 4 and the spindle kick is started. In step S6, the servo control unit 8 is instructed to turn on the tracking servo. This tracking servo moves the objective lens 27 of the optical pickup 5 in the radial direction so that the spot light follows the track on the disk 2. In step S7, the speed controller 16 is instructed to turn on the spindle servo. The spindle servo servo-controls the spindle motor 4 at a speed corresponding to the radial position so that the linear velocity of the disk 2 is constant.

When the spindle servo is started in step S7, the process proceeds to step S8. In step S8, the current track information written at the beginning of each block of the disc 2 is read, and in step S9, information corresponding to the table of contents of the disc 2 called TOC (Table Of Contents) written in the innermost circumference of the disc 2 is read. It is searched for and read out and stored in a memory in the system control unit 9.

Next, in step S10, waiting (pausing) for a predetermined time is performed, and in step S11, command input from the host computer 10 is awaited. When a command is input from the host computer 10, the process proceeds from step S11 to step S12. Step S12
Then, various command processes including the command shown in FIG. 1 described later are performed, and the process returns to step S10. Step S11
When there is no command input with, the processing ends.

Next, the procedure for executing the track access method of the present invention using the CD-ROM which employs the track search control device for the tracks having the above-mentioned structure will be described with reference to the flow chart of FIG. The flowchart of FIG. 1 is executed as one of the commands in the command processing step S12 of FIG. First, in step S31, the track number calculation unit 24 receives the track access input signal and calculates the number of tracks up to the target block.

Subsequently, in step S32, it is determined whether or not the current block is smaller than the target block. If it is determined that the current block is smaller than the target block, the number of tracks obtained by subtracting one from the number of tracks is calculated in step S33. The track / jump control unit 25 causes the track / jump control unit 25 to perform the track jump operation by using the track number calculation unit 24 and the track obtained by the subtraction in step S34 as a jump track to be jumped within one track before the target track.

On the other hand, when it is determined in step S32 that the current block is not smaller than the target block, the number of tracks obtained by adding one from the number of tracks is added to the track number calculation unit 24 in step S35.
In step S34, the track / jump control unit 25 executes the track jump operation by using the track obtained by the addition in step S34 as a jump track to be jumped within one track before the target track.

More specifically, the above operation will be described in detail. If there is a relationship of current block <target block, and there is a difference of 8 tracks as shown in FIG. 2, 8-1 = 7. By jumping by the number of tracks, it is possible to enter within one track before the target track by one jump.

On the other hand, in the relation of the current block> target block, if there is a difference of 6 tracks as shown in FIG. 3, by jumping 6 + 1 = 7 tracks, the target track is moved to the front. You can enter with one jump within one track. That is, the access time is shortened. As described above, be sure to jump within 1 track before the target block to eliminate the correction time,
Minimize access time.

[0023]

As described above, according to the present invention, in the track scanning of the disk, the track number calculating step for calculating the number of tracks from the current block to the target block by the calculating means, and the target block is larger than the current block. A block comparison step for determining whether or not the target block is larger than the current block, a subtraction step for subtracting one from the count track between the blocks, and a case where the target block is smaller than the current block. Since the track jump is performed by the tracking means by the addition step of adding one to the number of counting tracks and the number of tracks obtained in the addition step or the subtraction step, once in one track before the target track. You can enter by jumping in Practical effect that click access is faster is obtained.

[Brief description of drawings]

FIG. 1 is a flow chart diagram showing an embodiment of the method of the present invention.

FIG. 2 is an explanatory diagram for specifically explaining a track access method (current block <target block) of the present invention.

FIG. 3 is an explanatory diagram for specifically explaining a track access method (current block> target block) of the present invention.

FIG. 4 is a block diagram showing a configuration of a CD-ROM drive using a track search control device for carrying out an embodiment of the present invention.

5 is a functional block diagram of a servo control unit and a system control unit in FIG.

6 is a flowchart showing a schematic operation of the system control unit of FIG.

[Explanation of symbols]

 1 CD-ROM drive 2 disk 5 pickup 8 servo control unit 9 system control unit

Claims (1)

[Claims] 1. A track number calculating step for calculating the number of tracks from a current block to a target block by a calculating means in a track scanning of a disk, and a block comparing step for judging whether or not the target block is larger than the current block. A subtraction step of subtracting one from the number of counting tracks between the blocks when the target block is larger than the current block, and adding one to the number of counting tracks when the target block is smaller than the current block. A method of accessing a track of a disk, which comprises: an adding step;