JPH0352174A - magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent the step-out of a servo sector at the time of positioning heads by providing a timing adjustment area between an inner-peripheral-side recording area and an outer-peripheral-side recording area, where the number of the sectors per track differs. CONSTITUTION:(a)X(c) sectors per track are allocated to the outer-peripheral- side recording area A of the magnetic disk 1, (b)X(c) sectors in the inner- peripheral-side recording area B, and the number of the sectors of the greatest common divisor between the number of the sectors in the recording area A and that of the recording area B in the timing adjustment area C. When the heads 2a and 2b move from the recording area A to the recording area B, or in the opposite way, a control circuit 11 causes FF 10 to generate a servo sink signal with a cycle adjusted to the recording area A or the recording area B in the servo sector starting position of the timing adjustment area C. Consequently, the occurrence of the step-out of the servo sector is prevented even if the heads 2a and 2b move from the recording area A to the recording area B, or in the opposite way, and therefore stable servo control can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a magnetic disk device using a sector servo system.

``Prior Art'' Conventional magnetic disk drives include those in which the number of sectors per track is the same throughout the entire circumference of the data recording area of the magnetic disk, as shown in FIG. As shown in Figure (a), there are magnetic disks in which the number of sectors per track is different between the inner circumferential recording area and the outer circumferential recording area. In the case of Figure 4 (A), as shown in Figure 4 (B), the sector length (BL) of the inner recording area is considerably shorter than the sector length (AL) of the outer recording area. There are drawbacks. On the other hand, in the case of Figure 5 (a), the figure (
As shown in Figure 1), the sector length (AL') of the outer recording area is
) and the sector length (BL') of the inner recording area are the same.

On the other hand, there are two types of magnetic disk drives: one in which head positioning is performed using a servo control disk surface, and the other in which head positioning is performed by sector servo.

"Invention or problem to be solved" By the way, among the conventional magnetic disk devices listed above,
In the former case, since the number of sectors per track is the same in the inner and outer recording areas of the magnetic disk, the servo sectors can be synchronized well on both the inner and outer circumferences. That is, in this type of magnetic disk device, head positioning can be performed using the sector servo method.

On the other hand, in the case of the latter, the number of sectors per track differs between the inner recording area and the outer recording area of the magnetic disk, so if the sector servo method is adopted, the servo sector will change when the number of sectors changes. gets out of sync. For this reason, it is difficult to perform good servo control during head seek.

That is, this type of magnetic disk device is not suitable for head positioning using the sector servo method.

The present invention has been made in view of the above-mentioned circumstances, and has been made in view of the above-mentioned circumstances.
It is an object of the present invention to provide a magnetic disk device that can perform good servo control without losing synchronization even when the number of sectors per track is different from each other.

``Means for Solving the Problems'' A magnetic disk device of the present invention has an inner recording area and an outer recording area in which the number of sectors per track is different from each other in a magnetic disk device in which head positioning is performed by a sector servo. and a timing adjustment area between the inner recording area and the outer recording area, and when the head moves from the inner recording area to the outer recording area or in the opposite direction. The apparatus is characterized by comprising timing signal variable means for changing a timing signal for synchronizing servo sectors in the timing adjustment area.

The invention is characterized in that the greatest common divisor of the number of sectors per track in the outer circumference recording area and the inner recording area is set as the number of sectors per track in the timing adjustment area.

"Operation" In this invention, the timing for synchronizing the servo sectors when the head moves to a different recording area between the inner recording area and the outer scrap side recording area where the number of sectors per track is different from each other. A timing adjustment area is provided for changing the signal. By changing the timing signal for synchronizing the servo sectors in this timing adjustment area, the servo sectors will not become out of synchronization even if the head is moved from one recording area to the other.

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

FIG. 1 shows that a sector disk 1 of a magnetic disk 1 constituting a magnetic disk device according to an embodiment of the present invention has three recording areas A, C on the outer circumference side, the center, and the inner circumference side.
, B are allocated a different number of sectors per track. In this case, the central recording area (hereinafter referred to as
The number of sectors in the timing adjustment area) C is the greatest common divisor of the number of sectors in the outer recording area A and the number of sectors in the inner recording area B. That is, in the outer recording area A, there are ax sectors per track, and in the inner recording area B, there are bXc sectors, and the greatest common divisor C is the number of sectors in the central timing adjustment area C. Further, the relationship between each recording area is aXc<bXc<c. Here, FIG. 1(b) shows the timing of reading a sector for half a rotation of the magnetic disk 1, and the sector length is made to correspond to the time axis. In this case, since the number of sectors in the timing adjustment area C is the greatest common divisor of the number of sectors in the outer recording area A and the inner recording area B, the end of the third sector in the outer recording area A, At the end of the first sector in the timing adjustment area C, sector read timings can be matched.

Next, FIG. 2 is a block diagram showing the electrical configuration of the magnetic disk device according to this embodiment.

In this figure, 2a and 2b are heads, respectively, which are arranged with respect to the upper and lower recording surfaces of the magnetic disk l. 3
is a head switching circuit, which selectively selects one of the heads 2a and 2b based on the supplied switching signal. 4 is a read/write circuit that writes/reads data to/from the magnetic disk 1; 5 is a data control circuit, which controls writing/reading of data in the read/write circuit 4; in this case,
When reading data, control is performed so that recorded data excluding servo data from the disc recording signal is read. 6 is an interface circuit for exchanging data with Uiro equipment. A servo signal detection circuit 7 detects a servo signal from the read signal output from the read/write circuit 4. The servo signal detected by the servo signal detection circuit 7 is supplied as a trigger signal to the single yacht timer circuit 9, and is also supplied as a reset signal to the reset terminal of the flip-flop IO.

The one yacht timer circuit 9 is configured such that a timer value can be set from the outside, and outputs a set signal to the flip-flop IO immediately after the set timer value has elapsed. In this case, as will be explained below, the timer value is set corresponding to the sector length of the outer recording area A or the inner recording area B. When the set signal is supplied to the set input terminal of the flip-flop 10, the same flip-flop! 0
An "H" level servo sync signal (search timing signal) is output from the output terminal Q of the servo sync signal (search timing signal). This servo sync signal is a timing signal for synchronizing servo sectors. This servo sync signal is fed back to the servo signal detection circuit 7 and is also supplied to the servo data successive sequence circuit 8. After receiving the servo sync signal, the servo data read sequence circuit 8 performs a predetermined sequence operation, discriminates the servo data from the read signal, and supplies the servo data to the control circuit 1l.

The control circuit l1 includes a CPU central processing unit (not shown), R
It is composed of an AM (Random Access Memory), a ROM (Read Only Memory), an interface circuit, etc., and a program for controlling the CPU is written in the ROM. The control circuit 11 moves the magnetic disk l from the outer recording area A to the timing adjustment recording area C or from the timing adjustment area C to the inner recording area B based on the servo data supplied from the servo data read sequence circuit 8. The timer value setting of the one-shot timer circuit 9 is updated to that of the area to which the head has moved by determining the timing of movement of the head, and a switching signal is supplied to the head switching circuit 3 as necessary. In this case, the timer value of the outer recording area A is axe, the timer value of the inner recording area B is bXc, and C is the greatest common divisor of these. For example, if c=1 in FIG. 1 (C7),
There is a relationship of aXc=1/3 and bXc=I/2.

Next, the operation of the above structure will be explained with reference to the timing diagram shown in FIG. In this figure, (a) indicates a sector in the circumferential recording area A of the magnetic disk 1;
(b) is a sector in the timing adjustment area C, (c) is a sector in the inner recording area B, (2) is the servo sync signal output from the frib flop 10, (e) is the timer period of the one-shot timer 9 (“1 B and “11”
() and () indicate timer values set in the one-shot timer circuit 9, respectively. Hereinafter, the head 2 moves from the outer recording area A to the inner recording area B according to the illustrated trajectory.
Let's explain the seek control when moving a and 2b as an example.

When the heads 2a and 2b read servo data in the outer recording area A of the magnetic disk l as shown in FIG. A timer viaxC corresponding to the outer recording area A is set in the yacht timer circuit 9.

Now, the read signal output from the read/write circuit 4 is supplied to the servo signal detection circuit 7 and also to the servo data read sequence circuit 8. When a read signal is supplied to the servo signal detection circuit 7, the circuit 7
searches for a servo signal (not shown) among them. When the servo signal is detected, the one-shot timer circuit 9 is triggered in synchronization with the rise of the servo signal, and the flip-flop circuit 10 is reset. In this case, the servo sync signal is no longer output at the same time as the one-shot timer circuit IO is reset. Then, the one-shot timer circuit 9 sets the flip-flop IO immediately after the timer period for the outer recording area A has elapsed, as shown in FIG. 3(E). This makes the flip-flop I
A pulsed servo sync signal as shown in FIG. 3 (2) is output from the output terminal Q of O. In this way, a servo sync signal, which is a timing signal for synchronizing the servo sectors from the timing of the servo sectors in the outer recording area A, is created at the timing of the servo sectors in the outer recording area A.

Next, when the heads 2 and 2b reach the servo sector start position in the timing adjustment area C from the outer recording area A, the control circuit 11 sets a timer value corresponding to the recording area B in the one-shot/soto timer circuit 9. Then, a timer value corresponding to the inner recording area B is set in the one-shot timer circuit 9, and immediately after the time corresponding to the timer value has elapsed, a set signal is output from the one-shot timer circuit 9. , are supplied to the flip-flop 10. As a result, the flip-flop 10 outputs a servo sync signal having a pulse width as shown in FIG. 3(2).

In this case, the interval between the servo sync signals matches the interval between the servo sync signals in the inner recording area B.

Then, when the heads 2a and 2b reach the inner recording area B, the servo sync signal in the timing adjustment area C is continuous, and the servo sync signal in the same recording area B is output from the flip-flop IO at a period 1/2 of the period. be done.

In this way, the heads 2a and 2b are connected to the outer recording area A.
When moving from the inner recording area B to the inner recording area B or vice versa, a servo sync signal with a cycle corresponding to the outer recording area A or the inner recording area B is created at the servo sector start position of the timing adjustment area C. Therefore, even if the head moves from the outer recording area A to the inner recording area B or vice versa, no synchronization deviation occurs.

The above has described the case where seek control is performed from the outer recording area A to the inner recording area B, but the same applies to seek control in the opposite direction.

In addition, in the above embodiment, the timing adjustment area C is
Although the recording area is provided between the outer recording area A and the inner recording area B, a means that can simply detect the boundary between the outer recording area A and the outer recording area may be used. Electrical detection means and mechanical detection means are conceivable.

``Effects of the Invention'' As explained above, according to the magnetic disk device according to the present invention, the head can move between the inner recording area and the outer recording area where the numbers of sectors per track are different. Since a timing adjustment area is provided for changing the timing signal for synchronizing the servo sectors when the head is moved, even if the head is moved between different recording areas, only the servo sectors will be out of synchronization. Therefore, stable servo control can be achieved.

Furthermore, by using the sector servo method, it is possible to increase the storage capacity. Furthermore, compared to the case where a servo control disk surface is used, specifications for defects (scratches) on the same surface are no longer required. Further, an effect can be obtained in that a head and a circuit for continuously outputting signals from the servo control disk surface are not required.

[Brief explanation of drawings]

1 is a diagram showing the sector allocation of a magnetic disk according to an embodiment of the present invention; FIG. 2 is a block diagram showing a part of the electrical configuration of a magnetic disk device using the magnetic disk of FIG. Figure 3 is the second
FIG. 4 and FIG. 5 are diagrams showing the sector configuration of a conventional magnetic disk. ! ...Magnetic disk, A...Outer storage area, B...Inner storage area, C...Timing adjustment area, 7...
Servo signal detection circuit, 8... Servo data read sequence circuit, 9
...One-shot timer circuit, lO...
・Flip-flop, II...control circuit (7
to 11 constitute time variable means). signal

Claims (2)

[Claims] (1) A magnetic disk device that uses sector servo to position the head has an inner recording area and an outer recording area with different numbers of sectors per track, and these inner recording areas and outer recording areas a magnetic disk having a timing adjustment area therebetween; and a timing signal for synchronizing servo sectors in the timing adjustment area when the head moves from the inner recording area to the outer recording area or vice versa. What is claimed is: 1. A magnetic disk drive comprising: timing signal variable means for changing a timing signal. (2) The number of sectors per track in the timing adjustment area is set to be the greatest common divisor of the number of sectors per track in the outer recording area and the inner recording area. Magnetic disk device.