JPS63204570A - magnetic disk device - Google Patents

Abstract

PURPOSE:To rapidly and highly accurately execute the positioning of a magnetic head by selecting a magnetic head for reading out track information by a timing adjusting means and executing the positioning of the objective magnetic head. CONSTITUTION:A control means selects and drives a magnetic head for reading out track information out of plural magnetic heads 8a-10b based on the timing of the timing adjusting means started based upon a reference signal generated at every rotation of a motor 7 for driving magnetic disks 4-6. The control means positions the objective magnetic head so as to position the head on the center of the track based on the track information read out from the selected magnetic head in an initial selector. In respective selectors, similar positioning is executed in accordance with the rotation of the magnetic disk driving motor 7. Consequently, the magnetic head can be rapidly and highly accurate positioned without waiting the rotation of the motor 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic disk device used as an external storage means of a computer, and particularly to a magnetic disk device used as an external storage means of a computer, and particularly when positioning a magnetic head on a track at high speed and with high precision. The present invention relates to a magnetic disk device suitable for use in.

[Prior Art] As a technique for positioning a magnetic head on a track center in a magnetic disk device, there is a method in which servo data is written in advance on a part of a track, and positioning is performed based on a read waveform of the servo data by the magnetic head. Are known.

For example, as shown in FIG. 5, servo data 1 is written in each track 3 of each magnetic disk 2. As shown in FIG.

That is, it is written in a specific area (servo sector) immediately after the index signal St (see FIG. 6(c)) of track 3 having the format shown in FIG. 6(a).

When writing/reading data to/from the magnetic disk 2,
A magnetic head is sought onto track 3, and servo data 1 is read out in synchronization with an index signal Si generated every time a spindle motor for driving a magnetic disk rotates once.

After the magnetic head is positioned on the track 3 based on the read waveform of the servo data 1, data is written/read. FIG. 6(b) shows the read waveform by the magnetic head in this case.

[Problems to be solved by the invention] By the way, in the conventional magnetic disk device mentioned above,
Since the servo data l can only be obtained intermittently once per rotation of the spindle motor, there is a drawback that high-speed and highly accurate positioning control of the magnetic head cannot be performed.

The present invention was proposed in view of the above circumstances, and an object of the present invention is to provide a magnetic disk device that can position a magnetic head on a track at high speed and with high precision.

[Means for Solving the Problems] The present invention provides a plurality of magnetic heads for respectively writing and reading information on a plurality of magnetic disks, and a track provided for each sector of each track of each of the magnetic disks. control means that selects a magnetic head for reading information and the track information from among the magnetic heads and positions a target magnetic head based on the plurality of track information read by the selected magnetic head; The present invention is characterized in that it includes timing adjustment means that is activated based on a reference signal generated every rotation of a magnetic disk drive motor and that switches the timing at which the control means selects a magnetic head.

[Operation] According to the present invention, when positioning the target magnetic head, the control means operates based on the timing of the timing adjustment means activated based on the reference signal generated every rotation of the magnetic disk drive motor. When a magnetic head for reading track information from a plurality of magnetic heads is selected and driven, the magnetic head reads track information of the first sector.

Then, based on the next timing of the timing adjustment means,
When the control means selects and drives another magnetic head for not reading track information, the magnetic head reads track information of the first sector.

Then, in the first sector, the control means positions the target magnetic head so that it is at the center of the track based on the track information read by each of the selected magnetic heads. As the magnetic disk drive motor rotates, positioning is similarly performed in each of the following sectors.

As a result, track information can be obtained for each sector once during one rotation of the magnetic disk drive motor, allowing high-speed and highly accurate positioning of the magnetic head without having to wait for the motor to rotate. Can be done.

[Embodiments] Each embodiment of the present invention will be described below with reference to the drawings.

(1) First Embodiment In FIGS. 1(a) and 1(b), reference numerals 4, 5, and 6 indicate magnetic disks mounted on the spindle motor hub 7 of a magnetic disk device. A large number of tracks 4a and 4b are arranged on the upper and lower surfaces of the magnetic disk 4, respectively. Similarly, on each upper surface and each lower surface of the magnetic disk 5.6,
A large number of tracks 5a.

5bs Ga, Gb are arranged. For convenience, only a portion of the track is shown. In this case, track 4
a, 4b and track 5a, 5b1 track 5a, 5b
and the tracks 6a and 6b are arranged radially shifted from each other by a predetermined pitch. That is, tracks 5a and 5b
The tracks 6a and 6b are provided offset from the tracks 4a and 4b in the direction of the inner circumference of the magnetic disk by a distance smaller than "track pitch/3", and the tracks 6a and 6b are provided with a distance smaller than "track pitch/3".
3'' in the inner peripheral direction of the magnetic disk from the tracks 5a and 5b.

In addition, each track 4a to 6a is divided into eight sectors, and each gap in the 0 sector to the last sector (8 sectors) (see FIG. 2 (a) of GAP3C) is Format in advance
A pattern (track information) is formed. 8a, 8
b is a magnetic head for writing/reading to the magnetic disk 4; 9a and 9b are magnetic heads for writing/reading to the magnetic disk 5; 10a% and 10b are for writing/reading to the magnetic disk 6, respectively; It is a magnetic head.

On the other hand, a timing circuit (timing adjustment means) it, 12, 13, 14 (not shown) is provided on the control board of the magnetic disk device. Each of these timing circuits It~
14 will be explained with reference to the track format configuration and the read waveform of the magnetic head shown in FIGS. 2(a) and 2(b). 1, and absorbs the period L1 according to rotational fluctuations of the magnetic disk. Further, the timing circuit 14 is reset after the timing circuit 11 measures a period t1, and measures a period t2 corresponding to the sector length. The timing circuit 12 is reset after the time measured by the timing circuit 11, and the gap/GA is started from the beginning of the sector.
A period t3 up to the beginning of the format pattern of P3 is counted. Further, the timing circuit 13 is reset after the timing circuit I2 has measured the period t3, and the period t4 of the format pattern of the gap GAP3,
Time t5.

The case where, for example, the magnetic head 8a is positioned on the track 4a of the magnetic disk 4 when the above +1 is completed will be described. First, after rotating the magnetic disks 4 to 6 by the spindle motor, a control circuit (control means, not shown) outputs a read command signal to the magnetic head 9a accessing the track 5a of the magnetic disk 5. When the index base ring of the spindle motor hub 7 is detected by an index sensor (not shown) as the spindle motor rotates, an index signal Si is sent from the sensor (not shown).
is output. The timing circuit 11 is activated in synchronization with the rise of this index signal Si, and the gap/G
Time period 11 of AP1.

Next, after the timing circuit 11 has counted the period 11, the timing circuit 12 and the timing circuit I4 are reset, and the timing circuit ! 2 starts measuring time for period L3, and the timing circuit 14 starts measuring time for period rIIIL2.6Furthermore, after the timing circuit 12 has measured time for period t3, the timing circuit 13 is reset and starts measuring time for period t4.

During this period L4, the magnetic head 9a reads the format pattern of the gap CAI'3 of the O sector. The output signal level at this time is determined by the control circuit. When the timing circuit 13 finishes counting the period t4, the control circuit switches the magnetic head for reading from 98 to 10a based on the timing. And period t5
, the magnetic head 10a has a gap of 0 sector G
AP3 format pattern is not read. The output signal level at this time is determined by the control circuit.

Then, the control circuit causes the magnetic heads 9a and 10a to
The deviation distance and deviation direction of the magnetic head 8a from the center of the track 4a are determined from the output signal level read in the sector. Based on the deviation distance and direction, the head drive motor is driven to seek the magnetic head 8a by a predetermined cylinder in the inner or outer circumferential direction of the magnetic disk, thereby positioning it at the center of the track 4a.

Next, after the timing circuit 13 finishes timing for period t5, and the timing circuit 14 finishes timing for period L2, the timing circuit 12 and timing circuit 14 are reset again at that timing, and! Positioning of the magnetic head 8a is performed in the final ceftal sector in the same manner as in the case of the 0 sector. In this way, the magnetic head 8a is positioned in each sector as the spindle motor rotates (1<).

Note that the positioning of other magnetic heads is performed in the same manner as described above.

(2) Second Embodiment The magnetic disk drive according to this embodiment includes two timing circuits +2 and a timing circuit 13 having the same configuration as the first embodiment.
is provided. When an address mark detection signal Saw is output from an address mark detector (not shown) that detects the address marks AMI and AM2 of the track format, the timing circuit 12 outputs the same detection signal Sam.
It is reset in synchronization with the rising edge of
The period t6 up to the beginning of the format pattern No. 3 is counted. Also, the timing circuit 13 is the timing circuit 12.
It is reset after the measurement time of period 0 according to the above, and the periods t4 and L5 within the gap/GAPS are measured.

In the above configuration, for example, when positioning the magnetic head 8a on the track 4a of the magnetic disk 4, the control circuit outputs a read command signal to the magnetic head 9a, and then outputs a read command signal to the magnetic head 9a. 9a and 10a are switched and controlled, and the gap read by each head.
Find the output signal level of format pattern 3,
Positioning control is performed based on this.

First, as the spindle motor rotates, the address mark
Second address mark detection signal 5aI from the detector
11 is output, the timing circuit 12 is reset in synchronization with the signal 5aI11, and the timing circuit 12 starts counting the period t6. After measuring this period t6, the timing circuit 13 is reset. The control circuit controls the magnetic head 9a and the IO based on the timing of the timing circuit 13.
Switch a.

That is, the control circuit determines the output signal level of the format pattern of the gap GAP3 read by the magnetic hept 9a during the period t4. Next, at the end of the time period t4, the read head is switched from the magnetic head 9a to the magnetic head 10a, and the output signal level of the gap/GAP3 format pattern read by the magnetic head 10a during the period t5 is determined. Then, based on the above-mentioned output signal levels, track 4 of the magnetic head 8a is
By determining the deviation from the a center, the head drive ff
The DJ motor is driven to seek and position the head 8a by a predetermined cylinder.

Further, the positioning of the magnetic head 8a is performed in the 1st sector to the final sector in the same manner as in the case of the 0 sector.

In this way, as the spindle motor rotates, the magnetic head 8a is positioned in each sector.

Note that the positioning of other magnetic heads is performed in the same manner as described above.

Note that the following modifications can be considered for each of the above embodiments.

(2) The servo data D as shown in FIG. 4 may be provided in each servo sector of each track of the magnetic disk. In this case, there is no need to shift servo data in the disk radial direction for each magnetic disk surface, so even if the magnetic head is driven by a low-resolution stepping motor or a DC servo motor with an encoder, it can be used at high speed and high speed. Accurate positioning can be performed.

■Although the number of magnetic disks mounted is three, it is not limited to this.

(2) Although the number of sectors per track is 8, it is not limited to this.

(2) The generation means and detection means for the index signal Si are not limited to the above configuration.

[Effects of the Invention] As explained above, according to the present invention, a plurality of magnetic heads each write and read data on a plurality of magnetic disks, and track information provided for each sector of a customer track of each of the magnetic disks. and a control means for selecting a magnetic head for reading the track information from among the magnetic heads and positioning the target magnetic head based on the plurality of track information read by the selected magnetic head;
The present invention is configured to include timing adjustment means that is activated based on a base signal generated every rotation of the magnetic disk drive motor and that switches the timing at which the control means selects the magnetic head, so that the following effects are achieved. be able to.

■When positioning the magnetic head, track information can be obtained once for each sector, so it is not necessary to wait for the rotation of the magnetic disk drive motor to read the servo data after seeking the magnetic head, as in the past. There is no need to perform this process, and high-speed and highly accurate positioning can be performed.

■High-speed and highly accurate positioning can be performed without a special track format configuration.

[Brief explanation of the drawing]

1(A) and 1(B) are respectively a perspective view and a side sectional view showing a schematic configuration example of a magnetic disk according to the present invention, and FIGS. 2(A) to 2(C) are respectively a first embodiment of the present invention. Schematic diagram showing the structure of the track format, the read waveform of the magnetic head, and the index signal Si according to an example, FIGS. 3(A) to 3(C)
are schematic diagrams showing the structure of the track format, the read waveform of the magnetic head, and the address mark detection signal Sam according to the second embodiment of the present invention, and FIG. 4 shows another example of writing servo data D according to the present invention. Schematic diagram, Figure 5 is a schematic diagram showing the configuration of conventional servo data l, Figure 6 (A)
-(C) are schematic diagrams showing the structure of a track format, a read waveform of a conventional magnetic head, and an index signal Sf, respectively. 4a-6b...Magnetic disk, 8a-10b
...Magnetic head, 11-14...
Timing circuit (timing adjustment means), Si...
...Index signal, Sam...Address mark detection signal (reference signal).

Claims (1)

[Scope of Claims] A plurality of magnetic heads that respectively write to and read from a plurality of magnetic disks, track information provided for each sector of each track of each of the magnetic disks, and a device for reading the track information. a control means for selecting a magnetic head from the respective magnetic heads and positioning the desired magnetic head based on a plurality of track information read by the selected magnetic head; is activated based on a reference signal to
A magnetic disk drive comprising: timing adjustment means for switching the timing at which the control means selects a magnetic head.