JPH10188464A - Disk shape storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid frequent retrying and destruction of previous data by detecting the existence of a surface wobbling and eccentricity before the occurrence of retrying due to the existence, obtaining an optimum number of revolution capable of read and write based on this detection without retrying and performing control for setting this optimum number of revolution on a rotating drive system of a recording medium in advance. SOLUTION: The recording medium 1 is rotated by a spindle motor 2. A target track is accessed and its data is read out by a pickup 3 with its optical system in the focusing state on a data recording surface of the tracks of the recording medium 1 after its feed seek and track jump operation. Amplitudes of a focus error signal and a tracking error signal respectively are always monitored by a system controller 5. When an abnormality takes place in the focus error signal, this is judged to be a surface wobbling, and when an abnormality takes place in the tracking error signal, this is judged to be an eccentricity by the system controller 5, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read / write control technique in a disk storage device such as an optical disk device.

[0002]

2. Description of the Related Art A disk-type storage device, for example, an optical disk device, which is a typical example, uses a recording medium called an optical disk having a structure in which data is generally recorded on a spirally set track. Then, while the optical disk is rotated at a predetermined number of revolutions, data is written or the written data is read through an optical pickup. For this purpose, a focus operation and an operation called tracking are performed. The focus operation is an operation for focusing the optical system of the pickup on the data recording surface of the track, and the tracking operation is an operation of positioning the pickup on the target track, more specifically, the operation of setting the optical axis of the optical system of the pickup as the target. This is an operation of positioning the track at the center.

[0003] Basically, a disk-type recording medium such as an optical disk basically has a spiral track with high "circularity" on a plane that is uniformly flat. However, the flatness may be impaired for some reason, causing distortion, and the "circularity" of the track may be insufficient due to problems in manufacturing technology. When a recording medium having such a defect is rotated by an optical disk device, if there is a distortion that impairs the flatness, the interval between the pickup and the recording medium changes periodically, that is, a so-called surface wobble occurs, and the track has If the "circularity" is insufficient, so-called eccentricity occurs in which the distance from the rotation center of the recording medium changes for one track. When the degree of the surface shake exceeds a certain level, the focusing operation cannot sufficiently follow, and a state occurs in which data cannot be read or written. If the degree of the eccentricity exceeds a certain level, the tracking cannot sufficiently follow, causing not only a state where data cannot be read or written, but also a case where previous data is erroneously destroyed in the case of writing. .

When data cannot be read, a process called retry is performed. For example, in a retry in the case where the data could not be read, the pickup is once returned to the track inside the unreadable track by a track jump, the number of rotations is reduced, the reading is resumed from there, and the reading of the problematic track is performed again. In this case, if reading is not possible even at the once reduced rotation speed, the same retry is repeated again. For example, if reading is not performed even after repeating the retry five times, a reading error occurs.

[0005] As described above, in the conventional optical disk device, when the optical disk has a defect accompanied by surface runout or eccentricity, a state in which retry is frequently performed is likely to occur. The retry always involves a track jump and a change in the number of revolutions. Therefore, as the number of retries increases, the reading speed and the writing speed decrease significantly. In particular, when there is a defect with eccentricity, there is a possibility that the previous data is erroneously destroyed during the writing process.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the need for frequent retries even when using a defective recording medium accompanied by surface runout and eccentricity, and to prevent a previous recording from being performed during a writing process. The object is to effectively avoid data destruction.

[0007]

For this purpose, according to the present invention, so-called predictive control is carried out with respect to surface runout and eccentricity of a recording medium. That is, the presence of surface runout or eccentricity is detected before the occurrence of a retry due to these, and based on this detection, the optimum rotational speed at which reading and writing can be performed without performing a retry is determined, and this optimum rotational speed is determined for the recording medium. The control for setting the rotation drive system is performed in advance.

More specifically, a disk-type storage device that reads and writes data on a disk-shaped recording medium on which data is recorded on a track while rotating the disk-shaped recording medium at a predetermined number of rotations. Control of setting the optimum rotation speed in the rotation drive system of the recording medium in accordance with the degree of the detected surface wobble, and reducing the eccentricity of the track in the rotating recording medium. The control is performed so as to detect the detected eccentricity and set an optimal rotation speed in the rotation drive system of the recording medium according to the detected degree of eccentricity.

A control system relating to surface runout and eccentricity in such a disk type storage device according to the present invention can be constituted mainly by a CPU provided for normal reading and writing control.

It is reasonable to use a focus error signal relating to focus servo for detecting a surface runout in the disk storage device according to the present invention. That is, the focus error signal is a signal used to determine a focused state of the optical system of the pickup, and has an amplitude corresponding to a deviation from the focused state. Therefore, it is possible to easily and accurately detect the presence and degree of the surface shake from the state where the amplitude of the focus error signal becomes abnormally large. On the other hand, it is reasonable to detect eccentricity using a tracking error signal. That is, the tracking error signal is a signal used to determine the tracking state, reflects the intensity of the reflected light reflected from the track, and the optical axis of the pickup corresponds to the center of the track. Based on the state, it has an amplitude corresponding to the shift of the optical axis from side to side. Therefore, the presence and degree of the eccentricity can be easily and accurately detected from the state where the amplitude of the tracking error signal becomes abnormally large.

The predictive control relating to the runout and eccentricity of the disk-type storage device according to the present invention, that is, the detection of the runout and eccentricity of the recording medium and the setting of the optimum rotational speed based on the result are always performed. Alternatively, it can be performed using a time zone during which reading or writing is not performed, such as during idle operation. The optimum rotational speed according to the degree of surface runout or eccentricity is determined as the maximum rotational speed at which reading or writing can be performed under the condition that surface runout or eccentricity actually occurs at a certain magnitude. For this purpose, the same rotational speed as that of the retry is repeated in a state where the runout and the eccentricity are generated, so that the maximum rotational speed at which reading and writing can be performed is obtained. In some cases, it is also possible to store empirical data relating to the degree of surface runout or eccentricity and the maximum number of revolutions in a memory of a control system or the like in advance and use the data.

In the disk storage device according to the present invention as described above, if predictive control is performed using an idle operation time zone or the like, a retry as in the prior art is performed during an actual read operation or write operation. Frequent occurrence can be effectively prevented. Even when predictive control is constantly performed, frequent retries as in the related art can be effectively prevented thereafter by simply performing the same processing as retry in the process of obtaining the optimum rotational speed. As a result,
In the disk storage device according to the present invention, a significant decrease in the reading speed can be avoided even when a defective recording medium accompanied by surface runout or eccentricity is used. Further, in the disk storage device according to the present invention, even when a defective recording medium with eccentricity is used, it is possible to effectively prevent a situation in which previous data is destroyed during the writing process.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to a read-only type optical disk device. FIG. 1 shows a configuration of a main part of an optical disk device according to an embodiment of the present invention. The optical disk 1 is rotated by a spindle motor 2. Then, the pickup 3 accesses the target track by performing feed seek and track jump in a state where the optical system is focused on the data recording surface of the track of the optical disc 1, and reads data. While these operations are being performed, the focus error signal and the tracking error signal are continuously output from the focus servo system and the tracking servo system of the pickup 3.

FIG. 2 is a schematic illustration of the focus error signal and the tracking error signal. In the case where the optical disc 1 is normal without any defect, the focus error signal is a signal without a large fluctuation from the reference voltage. However, when the optical disc 1 has a surface wobble that swings up and down, the operation range of the focus servo abnormally increases, so that the wobble of the focus error signal also becomes abnormal. The same is true for the tracking error signal. If the optical disc 1 is eccentric, the signal swing becomes significantly larger than in the normal case.

These signals are input to the signal / servo processing means 4 and the system controller 5, respectively. signal·
The servo processing means 4 includes a digital signal processor (DSP) for processing a read signal based on the read data and a servo signal processor (SSP) for controlling tracking servo, focus servo, and the like. On the other hand, the system controller 5 is a CPU that functions for overall control of the optical disk device, and plays a central role in a control system for predictive control on surface runout and eccentricity in the present invention. A signal is output from the signal / servo processing unit 4 to a system controller 5 and a decoding processing unit 6 for processing a read signal into a computer signal.

The system controller 5 constantly monitors the amplitude of each of the focus error signal and the tracking error signal. If the above-mentioned abnormality appears in the focus error signal, it is determined that the surface is out of position, and the tracking error is detected. If any of the above abnormalities appear in the signal,
Judge as eccentric. As in the case of the retry, reading is repeated while changing the rotation speed of the optical disc 1, and the rotation speed at which reading can be performed stably is obtained. For example, 8 times speed (400
0 rpm) as a normal rotation speed, and then gradually reduce the rotation speed, or use the lowest 1 × speed (500 rpm).
pm), the rotational speed is gradually increased to find the optimal rotational speed. The determination of the optimum rotational speed is performed using an error correction signal.

The error correction signal is a signal for transmitting a result of performing an error correction process on the data that cannot be read. That is, the error correction signal includes information on the number of blocks including data that could not be read.
Here, the block is set by dividing a track, and serves as a data recording unit area. The number of blocks in the error correction signal is generally about several per unit time under normal rotation speed and no normal runout or eccentricity, but increases to several hundred per unit time if normal runout or eccentricity exists. I do. Therefore, by determining whether or not the number of blocks in the error correction signal is about several normal values, the optimum rotation speed can be obtained.

After the optimum rotation speed is determined for a defect due to surface deflection or eccentricity in the currently used optical disk 1, the spindle motor 2 is controlled based on the optimum rotation speed.

[0019]

As described above, according to the present invention, it is possible to read and write even a recording medium having a defect such as surface runout or eccentricity without frequent retries, thereby increasing the processing speed. It is also possible to effectively prevent a situation in which previous data is destroyed during the writing process.

[Brief description of the drawings]

FIG. 1 is an exemplary configuration diagram of an optical disc device according to an embodiment;

FIG. 2 is an explanatory diagram of a focus error signal and a tracking error signal.

[Explanation of symbols]

 1 recording medium 3 pickup

Claims (5)

[Claims] A disk-type storage device for reading and writing data on a disk-shaped recording medium on which data is recorded on a track while rotating the disk-shaped recording medium at a predetermined rotation speed. The control of setting the optimal rotation speed according to the degree of the detected surface runout in the rotation drive system of the recording medium, and detecting the eccentricity of the track in the rotating recording medium, A disk-type storage device characterized in that control is performed to set an optimum rotation speed according to the detected degree of eccentricity in a rotation drive system of a recording medium. 2. A disk-type storage device that reads and writes data via a pickup while rotating a disk-shaped recording medium on which data is recorded on a track at a predetermined rotation speed. A disk-shaped storage device which detects a runout of a recording medium in the medium and performs control for setting an optimum rotation speed in a rotation drive system of the recording medium according to the detected degree of the runout. apparatus. 3. A disk-type storage device which reads and writes data via a pickup while rotating a disk-shaped recording medium on which data is recorded on a track at a predetermined rotation speed. A disk-shaped storage device for detecting the eccentricity of a track in a recording medium in the medium and performing control for setting an optimum rotation speed according to the detected degree of eccentricity to a rotation drive system of the recording medium. apparatus. 4. The disk-type storage device according to claim 1, wherein the surface deviation of the recording medium is detected using a focus error signal relating to a focus servo. 5. The disk storage device according to claim 1, wherein the eccentricity of the track is detected using a tracking error signal relating to a tracking servo.