JPH01277379A - Disk device - Google Patents

Abstract

PURPOSE:To attain interchangeability with an ordinary medium by means of common hardware by utilizing a control circuit provided with servo information and adding a processing means for reading out a medium having no servo information. CONSTITUTION:When servo information is not recorded on a recording medium Di, a detecting means 11 measures the amplitude of a reproduced signal on an objective track at plural positions of the track and a microprocessor 18 compares the preceding amplitude data measuring value with a current measuring value, micro-steps a head 6 in the increasing direction of the amplitude by referring a head moving direction at the time of preceding measurement and controls a head moving actuator 15 so as to set up an on-track state. Thus, interchangeability can be obtained without preparing exclusive circuits for the recording medium with servo information and the ordinary medium having no servo information.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention particularly relates to a drive device having a servo mechanism that performs tracking using a servo pattern formed on a data recording surface.

[Conventional technology]

In recent years, disk devices such as floppy disks have become increasingly smaller and have higher recording density.
The narrow track of disks as recording media,
Densification is progressing. However, as density increases in this way, it becomes difficult to accurately set the head position with respect to the recording track by simply moving the head using a conventional step motor or the like. As a method to solve this problem, a method has been adopted in which servo information for tracking is recorded on a recording medium and head tracking is performed based on this information.

As a result, as mentioned above, media with tracking servo information recorded and conventional media without servo information coexist, and compatibility has been raised as an issue in devices that handle these media. .

With a device equipped with a servo mechanism that performs head tracking from information, there are two ways to read a medium that does not have servo information (hereinafter referred to as a conventional medium): (1) Positioning is performed using open-loop control such as a stepping motor as a tracking actuator. If you are using one that is possible, move the head to a position that you think is roughly in the center of the track and read it.

(2) Move the head to a position that is thought to be the target track position and check whether there is an error in the read data information, such as ID information or data part. If there is an error, move the head position slightly to correct the error. Search for the missing position.

It can be roughly divided into two methods.

[The problem that the invention is trying to solve] However,
In the case of method (1) above, open-loop control simply moves to a position that is thought to be the target track position and reads it, so if the accuracy of the stepping motor etc. is poor, the track may shift and it will not be possible to read correctly. .

In addition, in the case of method (2), it is difficult to control the head position on the drive device from the system side because the system to which the drive device is connected determines whether there is an error in the data. Processing time also becomes long, and if a circuit for determining data errors is added to the drive device, the circuit scale becomes large and the cost of the device becomes high.

[Means for solving problems]

The present invention has been made for the purpose of solving the above-mentioned problems, and is a disk device that controls the position of a head relative to a track based on servo information recorded on a recording medium. head moving means for moving the head according to the output of the detecting means to correct a deviation with respect to the target track; control means for measuring the amplitude of the head at a plurality of locations on the track and controlling the operation of the head moving means based on the signal level. This makes it possible to have compatibility with both media without having to prepare dedicated circuits for each.

〔Example〕

Hereinafter, one embodiment of the disk device according to the present invention will be described in detail with reference to the drawings.

1 to 6 are diagrams showing an embodiment of the present invention and its explanation, FIG. 1 is a block diagram showing the configuration of a disk device of the present invention, and FIGS. 2(a) and 2(b) are FIG. 3 is an operation flowchart of the device of the present invention, FIG. 4 is a diagram showing the timing relationship with the format, and FIG. 5 is a diagram showing the timing of the signal. The diagram shown in FIG. 6 is a diagram showing measurement results from the amplitude measurement circuit. Embodiments of the present invention will be described below using the above-mentioned figures.

First, before explaining the circuit operation according to the present invention, the second
The track layout on a magnetic disk as a recording medium considered as an object and the positional relationship between the head and the head will be explained with reference to the drawings. The track format shown in FIG. 2(a) is an example of a servo pattern method called sector servo, which serves as servo information for head tracking when recording/reproducing in the drive device of the present invention. Patent application 1986-4020 filed earlier by the applicant
When the magnetic head 6 travels in the force direction indicated by the arrow AA in the figure, it detects signals with two different frequencies, Fl and F2, and uses this as the start timing of the servo pattern for the subsequent A-
Sampling the pattern of D, AIB, C, D
It operates to correct track deviation by comparing the amplitudes of any two. The circuit block at this time is shown in Fig. 1, but details are given in the above-mentioned patent application published in 1983.
No. 2-4020.

The track layout shown in FIG. 2(b) is a conventional recording medium that does not have servo information, and has a pitch that is 1/3 of the track pitch in FIG. 2(a), and the track width is approximately 2.
(This is called a conventional medium. For example, in the case of a 3.5-inch Propy disk, the track pitch of the conventional medium is 135 TPI. The servo pattern shown in Figure 2 (a) is It is 405TPI.

).

In the figure, the track OO and head position a indicate the state in which the head is completely inside the track (on-track state), and the track 01 and head position indicate that the head is at the width of the recording track. It shows a state of deviation from . Track 01 with track deviation
If a read operation is performed in this state, the recorded data cannot be read correctly due to a drop in output due to track misalignment, or an error will occur. Therefore, with the disk shown in FIG. 2(a), the head position can be controlled correctly relative to the track using servo information, but when the head accesses the disk shown in FIG. 2(b), the track servo does not work, so the head As already shown, track deviation occurs. Therefore, the operation according to the present invention will be explained below. The circuit block shown in FIG. 1 is originally a block diagram configured to perform track servo on a medium with the track servo pattern, and in the present invention, this hardware is used, and the processing flow is executed by a microprocessor. The on-track operation of conventional media can be performed by changing the .

Here, the circuit configuration shown in FIG. 1 will be explained.

FIG. 1 is a block diagram showing the configuration of a disk device according to the present invention. In the figure, Di is a magnetic disk as a recording medium, l is a disk rotation motor that rotates the disk D at a predetermined speed, and 2 is a disk rotation motor that will be described later. a motor drive circuit 3 that rotationally drives the motor 1 according to instructions from the microprocessor;
4 is an index sensor that detects the rotation of the disk, such as an index hole on the disk, 4 is a detection circuit that supplies a signal according to the rotational state of the disk to the microprocessor 18 in accordance with the detection output of the index sensor 3, and 5 is a cassette. This is a disk identification switch that detects whether the disk is one with servo information or a conventional medium from the identification hole etc.

6 is a magnetic head for recording and reproducing data on the recording track on the magnetic disk Di; 7 is a recording circuit that supplies a recording current to record data to the magnetic head; 8 is a magnetic head that The reproducing circuit 8 outputs data read from the disk D, and outputs a data signal and a servo information signal shown in FIG. 2 from the reproduced signal.

Reference numeral 9 controls the recording circuit 7 to perform data recording in accordance with the data signal supplied via the input/output interface 10 and an external host computer connected to the disk device, and also controls the recording circuit 7 to perform data recording, and reproduces data supplied from the reproduction circuit 8. It is a control logic circuit that supplies signals to an external host computer via an input/output interface 10. and recording circuit 8. Each control logic circuit 9 is controlled by a microprocessor 18 and executes each operation at a predetermined timing.

11 is a servo signal detection circuit that detects the servo information shown in FIG. 2 detected and output by the reproducing circuit 8; 12 is an integration gate that integrates the servo information signal according to instructions from the microprocessor 18 and outputs its average level; 13 is a sample and hold circuit that samples and holds the output level of the integration circuit in accordance with instructions from the microprocessor 18; 14 is a sample and hold circuit 13;
This is an A/D converter that converts the output of the microprocessor into a digital signal and supplies it to the microprocessor. That is, when the servo signal detection circuit 11 detects the leading two-frequency signal 'l+f2 of the servo information shown in FIG. A sampling pulse A to D is generated, and the amplitude at each position of each pattern A to D is held.

The level of each signal pattern is determined by the A/D converter 14.
The digital signal is converted into a digital signal and supplied to the microprocessor 18, and the positional deviation of the head relative to the track is detected.

Incidentally, this servo operation itself is described in detail in the aforementioned Japanese Patent Application No. 62-4020.

15 moves the magnetic head 6 in the radial direction of the disk, that is, to each recording track, and can finely adjust the head position according to the amount of deviation between the head 6 and the recording track detected based on the servo information described above. This is an actuator for moving the head, and is driven by, for example, a stepping motor. 16 is actuator 1 for moving the head
5 is a drive circuit that drives 17 is a microprocessor 18
This is a D/A converter that converts the control signal supplied from the controller into an analog signal and supplies the drive circuit 16 with a signal corresponding to the amount of movement of the actuator.

Further, as described above, the microprocessor 18 performs recording and reproduction on the motor drive circuit 2 for rotating the magnetic disk, the drive circuit 16 for the actuator for moving the head, and the disk according to information from each sensor and control information from the outside. It collectively controls the control logic circuit for the servo information detected on the disk, the integration circuit (integration gate) 12 for detecting servo information detected from the disk, the sample hold circuit 13, etc., and will be referred to as the CPU hereinafter.

Next, the operation of the disk device of the present invention will be explained with reference to the flowchart shown in FIG.

First, when a cassette such as a floppy disk as a magnetic disk is inserted into the drive device (step 1), a medium identification hole (not shown) formed in the cassette is identified by the cassette detection switch 5 (step 2). As a result, if the disk has servo information, 5te
Proceeding to p3, a head tracking servo operation is performed according to the servo information described above, and if the medium is a conventional medium, the control program enters the processing routine from 5tep4 onwards.

Here, when the system side such as the host computer issues a seek command to the target track for data reading (step 4), the microprocessor 18
/A converter 17. The head 6 via the drive circuit 16
A seek operation is performed to the target track (step 5).
). After a seek, an index sensor detects an index signal that occurs once per disk revolution,
In synchronization with this, the reproduction amplitude within one rotation track is measured. The measurement timing at this time is as shown in Fig. 4, after detecting the index signal shown in Fig. 4 (a), and then detecting the gap between each sector in the recorded format as shown in Fig. 4 (b). The configuration is such that the amplitude of the gap is measured using the sampling pulse shown in FIG. 10(d) that is generated at the timing shown in FIG. This is to reduce the influence of recording density etc. by measuring the same recorded pattern portion.

That is, after the index signal is detected by the index sensor 3 at step 5tep6, the reproduction signal level outputted by the integrating circuit 12 is held by the sample hold circuit 13 after a predetermined time has elapsed by the timer 1. (step 7.8).

An operation timing chart at this time is shown in FIG.

The figure (a) shows the relationship between sectors and gaps between sectors, and (b)
is an integration gate pulse that operates the integration circuit 12, (c)
(d) is the waveform of the output point P of the integrating circuit 12, and (e) is the sampled and held pulse signal.

Next, proceed to 5tep9, and after the predetermined time has elapsed by timer 2, the measurement number counter is incremented by 1 at 5tep1O, and 5t
It is checked at epH that the planned number of times (N times) has been reached, and if it has not reached N times, it returns to 5tep8 again and N
Measurements are taken until the number of times is reached. When measurements are performed N times, 5t
Moving to ep12, the measurement data is checked N times.

FIG. 6 is for explaining the checking operation of the measured data, and shows the case of 9 sectors per 1 track. FIG. 6A shows a case where the head 6 is on-track with respect to the target track, and all measured levels are equal to or higher than a predetermined determination level. Same figure (
b) is a case where the vehicle is off-track, and none of the measurement levels has reached the determination level. This puts you on track.

Off-track can be determined (step 3)
).

In addition, since the reproduction amplitude decreases from the outside to the inside depending on the track position of the disk, the amplitude of the outermost track is used as a reference for each track position, and a coefficient that takes into account the decrease in head output due to a decrease in relative speed and the decrease in output due to an increase in linear recording density. The judgment level for each track is set by .

That is, if it is on track at 5tep13, the process proceeds to 5tep14 and outputs a seek complete output signal indicating that the seek operation is completed to the system side,
Enable control on the system side (step 15)
. Thereafter, if a seek operation command is issued again on the system side, the process returns to 5tep4 and the above-described operation is repeated.

On the other hand, if it is off-track at 5tep13, the process moves to 5tep16, where the previous amplitude data measurement value and the current measurement value are compared, and the head movement direction at the previous measurement is referred to. , the head movement actuator 15 is controlled so that the head 6 is microstepped in the direction of increasing amplitude and placed on track (
step17. 18. 19).

Note that if the current measurement is the first time and no previous measurement value exists, the head is moved in one direction and the head position is detected by the next measurement.

Note that the microstep operation is generally used for micro-feeding of rotary or linear stepping motors, and is driven by changing the current balance of the drive coil.

The off-track explained in the above embodiment refers to the case where the track position is deviated, but for example, in the case of eccentricity due to chucking deviation of the cassette, the amplitude is changed as shown in Fig. 6(c). There is an increasing part and a decreasing part in one rotation period.

As a method for dealing with this case, it is also possible to issue a microstep command for each sector portion and perform tracking servo like a medium with a servo pattern.

However, in this case, it will be necessary to measure the amplitude for one rotation or more and then perform learning control processing based on this.

〔Effect of the invention〕

As explained above, according to the disk device of the present invention,
Complete compatibility with conventional media using common hardware is achieved by adding a processing means for reading conventional media without servo information using a control circuit provided for track servo for disks with servo information. This has the effect of making it possible to realize high performance and read conventional media reliably without increasing manufacturing costs.

Although the present embodiment has been described using a magnetic disk device and a magnetic head as an example, the present invention is not limited to this, and the present invention can be applied to, for example, an optical detection device. can do.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a disk device according to the present invention, FIGS. 2(a) and (b) are diagrams for explaining patterns of tracks and servo information formed on the disk, and FIG. A flowchart for explaining the present invention in detail, FIG. 4 is a timing chart for explaining the timing of the signal detection operation of the present invention, and FIG. 5 is a timing and waveform diagram for explaining the signal detection operation of the present invention. , FIG. 6 is a waveform diagram of the measurement signal. Patent applicant: Canon Electronics Co., Ltd. M AA No. 67

Claims (1)

[Claims] A disk device that controls the position of a head with respect to a track based on servo information recorded on a recording medium, comprising a detection means for detecting the servo information, and a detection means for moving the head according to the output of the detection means to move the head to a target track. head moving means for correcting the deviation with respect to the target track; and when the recording medium is not provided with the servo information, the detecting means measures the amplitude of the reproduction signal of the target track at a plurality of locations on the track, and based on the signal level, the A disk device comprising a control means for controlling the operation of a head moving means.