JP2770424B2 - Track positioning method for magnetic disk - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention determines the position of track 0, which is the outermost track of the data area of a magnetic disk, and moves the head to track 0 of the magnetic disk. It relates to a track positioning method.

2. Description of the Related Art In order to write servo data for positioning a head on a magnetic disk used in a magnetic disk device,
A data area is provided with an innermost track and an outermost track, and this track is dedicated to servo data.
There is an IDOD method. In the IDOD system, tracks are formed at a high density on a magnetic disk, especially a hard disk due to an increase in capacity. Therefore, in order to accurately position the head, it is necessary to accurately determine the position of track 0, which is the outermost track of the data area of the hard disk.

Conventionally, track 0 of the hard disk in the IDOD system
Is determined by a microprocessor based on the state of a photo-interrupter installed at the rearmost part of the head driving mechanism and a step motor for moving the head. That is, when the head is at the track 0 position, the photo interrupter detects the head arm and sends out a detection pulse to the microprocessor, while the microprocessor monitors the phase state of the step motor. When the photo interrupter detects the head arm and the stepping motor becomes zero phase, the microprocessor determines the track where the head is located as track 0. Then, the microprocessor sends a track 00 signal, which is a signal indicating that the head is positioned on track 0, to an interface (for example, a disk controller).

Problems to be Solved by the Invention Meanwhile, the photo interrupter is installed at the rearmost part of the head drive mechanism so as to detect the head arm when the head is at the track 0 position of the magnetic disk. Therefore, when an impact or the like is applied to the magnetic disk device, the position of the photo interrupter fluctuates.
There is a problem that a read error occurs because the position also changes.

In addition, a change in temperature causes expansion and contraction of the magnetic disk, which causes a thermal off-track in which the position of the head and the track 0 of the magnetic disk is shifted, so that the position adjustment of the photo interrupter is always required, which is complicated. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to provide a magnetic disk track positioning method for avoiding off-track due to impact or temperature change.

Means for Solving the Problems In order to solve the above problems, according to the present invention, there is provided a magnetic disk in which servo data for positioning a head is written on an outermost track and an outermost track of a data area. In the track positioning method of the magnetic disk for determining the position of the track 0 in order to locate the track 0 which is the outermost track of the data area of the magnetic disk, Further, track-1 and track-2 are sequentially formed from the inside, and the first signal data A as an output signal and the non-output signal after the first signal data A are provided at the center position of the track-2. Track 00 signal data for determining the position of the track 0 constituted by the second signal data B Previously write data, when the head detects the track 00 signal data,
The magnetic head is positioned at the track 0 by moving the head in two tracks inward with reference to the detection position of the track 00 signal data.

According to the above-described track positioning method, the first and second signal data are located at the center position of track-2 of the track-1 and track-2 formed outside the position of track 0 in the data area of the magnetic disk. Track 00 signal data composed of A and B is written in advance. The track 00 signal serves as a reference for positioning the head at the track 0 position.

When the head detects the track 00 signal data, the head is moved inward by two tracks based on the detection position of the track 00 signal data. This allows
The head is positioned at the track 0 position.

As described above, the head is positioned at the track 0 position based on the track 00 signal data written in advance on the magnetic disk. Therefore, even if an impact is applied or the temperature changes, the track 0 position is accurately determined, and the head position is determined. Off-track at the track 0 position can be avoided.

Track-2 to which track 00 signal data is written is not directly formed outside track 0, but
Track 1 is interposed between track 0 and track 2, and is formed outside track 1. Therefore, track-1 magnetically defines track 0 and track-2, and thus the track 00 signal data (magnetic recording data) written to track-2.
Can be prevented from affecting various data written in track 0.

Embodiment Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a state in which track 00 signal data indicating the position of track 0, which is the outermost track of the data area, is written in advance outside the data area of the magnetic disk in the IDOD method in the method of the present invention. It is. In FIG. 1, tracks 0, 1,... Are data areas, and tracks-1, -2 are newly formed outside this data area. And track-2 has a track
00 signal data A, B, etc. are written. Signal data A
Is the track width d and pulse width τ _{1 at} the center of track-2.
, And the signal B is in a state where nothing is written after the signal data A in the width τ ₂ . The signal data C and D shown in FIG.
This is servo data having a pulse width τ ₃ shifted in the reverse direction by 1/2, and is signal data for positioning the head.
Here, since track-1 is provided outside the data area, it is to prevent signal data of track-2 from entering the data area (track0). That is, in the IDOD system, track 0 is set as a track dedicated to servo data.

Next, FIG. 2 shows a block diagram of an embodiment of a magnetic disk drive to which the method of the present invention is applied. In FIG. 2, 1
Is a disk (hard disk) in which the track 00 signal data is written in advance as described above, is fixed to the rotating shaft 3 of the motor 2, and is rotated at a constant rotational speed by the motor 2. Further, a head 4 is mounted on the head arm 5 so as to be closely opposed to the surface of the disk 1. In the present embodiment, the hard disk 1 on one side is
Although a single disk is shown, a double-sided disk may be used, and the same applies to a plurality of these disks, and a head is configured accordingly.

The head 4 is connected to an amplifier 6, and a signal detected by the head 4 is amplified by the amplifier 6 and then supplied to a servo data detector 7. The servo data detector 7 envelope-detects and integrates a signal of the frequency (for example, 2.5 MHz) of the servo data, and supplies the obtained level to the microprocessor 8.

The microprocessor 8 has an A / D converter 8a, a timer circuit 8b, a storage circuit 8c, and the like built therein, and the A / D converter 8a digitizes and captures the above level. The microprocessor 8 outputs the head transfer data, and outputs the track 00 signal when the head 4 is finally positioned on the true track 0. Here, the head transfer data is
After being converted into an analog signal by the D / A converter 9, the signal is amplified by the amplifier 10 and supplied to the stepping motor 11. Step motor 11
As a result, the head arm 5 is driven, whereby the head 4 is transferred to the radially inner side or outer side of the disk 1.

The motor 2 is provided with a rotation detector 12.
An index signal is generated for each rotation of the motor 2 and supplied to the microprocessor 8. And the head arm 5
Is provided with a sensor 13 (for example, a photo interrupter), which detects the head arm 5 when the head 4 is on the track 0 position of the disk 1,
The detection pulse is supplied to the microprocessor 8. In addition,
The sensor 13 is for reducing the time for the head 4 to detect the track 00 signal data, and is not always necessary.

Next, FIG. 1 and FIG.
This will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 shows a head output when the head 4 detects the track 00 signal data, and FIG. 4 is a flowchart of one embodiment of the track 0 positioning operation. First, when the power is turned on to the magnetic disk device, the head 4 is moved to an initial setting position preset in the microprocessor 8, that is, a position where the head arm 5 is detected by the sensor 13 by driving the step motor 11, and This position is a temporary track 0 position. Next, the head 4 is moved outward by two tracks (step 20 in FIG. 4) and positioned at track-2. At this time, it is determined whether or not the index signal has risen from the rotation detector 12 of the motor 2 (step 21), and if not, it stands for one rotation time 17 [ms] of the disk 1. Wait for climb (step 22), 17 [m
s] If it does not rise after elapse, it is determined that the disk drive is faulty (step 23), that is, it is confirmed that the index signal is in the signal output state at the fall and the index signal is not output at the initial stage. .
On the other hand, when it is confirmed that the index signal is not output in the rising state, it is determined in 17 ms whether or not the index signal has fallen to the output state (steps 24 and 25). If the index signal is not output for 17 [ms], it is determined that a disk drive fault has occurred (step 26).

Here, when the index signal falls and is output from the rotation detector 12 as shown in FIG. 3 (B), the timer circuit 8b of the microprocessor 8 operates (step 27), and the falling index signal is stabilized. Wait for the elapse of 120 [μs] (step 28).

Next, after a lapse of 120 [μs] from the fall of the index signal and the level of the signal data A has stabilized, the timer circuit 8b of the microprocessor 8 operates (step 2).
9). Then, the head 4 is connected to the track-2 of the disk 1.
(FIG. 1 and FIG. 3 (A)), and outputs the output signal to the A / D converter 8a of the microprocessor 8 via the amplifier 6 and the servo data detector 7. Supply. The A / D converter 8a converts the analog signal into a digital signal (step 30) and stores it in the storage circuit 8c (step 31). These are performed within 200 [μs] time,
When 200 [μs] elapses from the timer start (step 29) (step 32), the head 4 detects a signal state (signal data B) after the signal data A (FIGS. 1 and 3 (A)). This output signal is similarly transmitted to the A / D converter 8a of the microprocessor 8 through the amplifier 6 and the servo data detector 7.
Supplied to The A / D converter 8a converts the analog signal into a digital signal (step 33) and stores it in the storage circuit 8c (step 34). As shown in FIG. 3B, the signal data A and the signal data C and D are distinguished by their levels.

Next, a storage circuit 8c to the stored signal data A pulse width tau ₁ of high level microprocessor 8 (being written detecting signal data), and the signal data B
There (detected that nothing is written) width tau ₂ of the low level when the (step 35), the track 0 location is determined to be located in 2-track direction than the track 2. Then, the head 4 is moved in two tracks inward by the step motor 11 via the D / A converter 9 and the amplifier 10 based on the servo data of the signal data C and D (FIGS. 1 and 3A). (Step 37). As a result, the head 4 is positioned on the track 0 of the disk 1, and the microprocessor 8 outputs a track 00 signal to that effect to an interface (for example, a disk controller) (step S1).
38).

On the other hand, if the signal data A is at the low level or the signal data B is at the high level in steps 35 and 36, the head 4 is not at the position of the track-2, and the track 00 signal data is detected. The operation is re-started (step 39).

As described above, since the detection by the photointerrupter serving as the sensor 13 is not a factor for determining the position of the track 0, it is possible to prevent the position of the track 0 from fluctuating due to the position of the photointerrupter fluctuating due to an impact on the apparatus. . Further, it is not necessary to adjust a sensor (photointerrupter) necessary for preventing a thermal off track (track 0 position shift) caused by a temperature change.

As described above, according to the track positioning method of the magnetic disk of the present invention, the position of the track 0 is determined by the track 00 signal data written in advance on the magnetic disk, so that the position of the track 0 is accurately determined. It is possible,
The displacement of the track 0 due to an impact or a change in temperature can be prevented, which is extremely useful in practice.

Also, a track-track is located between track 0 and track-2.
Since track 1 is present, track-1 magnetically defines track 0 and track-2, so that track 00 signal data (magnetic recording data) written to track-2 is written to track 0. Data can be prevented from being affected.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a state in which track 00 signal data is previously written on a magnetic disk, FIG. 2 is a block diagram of an embodiment of a magnetic disk device to which the method of the present invention is applied, and FIG. FIG. 4 is a diagram for explaining detection of track 00 signal data in the head, and FIG. 4 is a flowchart of a track 0 positioning operation executed by the microprocessor. 1 ... Disc, 4 ... Head, 7 ... Servo data detector, 8 ... Microprocessor, 11 ... Step motor, 12 ... Rotation detector, 20-39 ... Step, A, B ...
Track 00 signal data.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 21/08

Claims (1)

(57) [Claims] 1. A magnetic disk on which servo data for positioning a head is written on an outermost track and an outermost track of a data area, wherein the head is located on a track 0 which is an outermost track of the data area of the magnetic disk. In the track positioning method of the magnetic disk for determining the position of the track 0, the track 1 and the track 2 are sequentially formed from the inner side outside the track 0 position of the data area of the magnetic disk. And at the center position of the track-2, first signal data A as an output signal and second signal data B as a non-output signal after the first signal data A. Track 00 for determining the track 0 position
When the head detects the track 00 signal data, the magnetic head is moved inward by two tracks with reference to the detection position of the track 00 signal data, thereby moving the magnetic head to the track 0. A track positioning method for a magnetic disk, comprising: