JPH061616B2 - Servo signal recording / playback method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo signal storage / reproduction system in a magnetic disk device, and more particularly to a spiral servo track and concentric servo track switching means.

In recent years, the technical progress of magnetic disk devices has been remarkable, and attention has been paid to the improvement of storage density and high-speed processing function, and they have become important as input / output devices in computer systems. In this disk device, however, shortening the access time for positioning the magnetic head is an important issue, and the development of means capable of higher speed processing is desired.

[Conventional technology]

3 (a) and 3 (b) show a schematic view and a developed view of a conventional concentric servo track surface. Fig. 3 (a) shows the concentric servo tracks of apparently cut in a certain radial direction and unfolded at the same time.
As shown in (b), the numbers for each servo track are the same on the left and right. FIGS. 4 (a) and 4 (b) show a schematic view and a development view of a conventional spiral servo track surface. This track is apparently cut in a radial direction of a concentric servo track of FIG. 3 (a). This is the same as the case where the tracks are connected by shifting one track in the radial direction, and therefore the left and right track numbers in the development view are shown shifted by one.

FIG. 5 shows a magnetization pattern of a two-phase servo signal recorded across adjacent tracks of the servo tracks of FIG. 3 (a) or FIG. 4 (a), that is, two tracks, and The relative positional relationship with the track position on the corresponding data surface is shown. In the figure, T indicates the track width of one servo track. 51 is the core of the servo head that reproduces the servo signal, W ₁ is the core width, and 52 is the core of the magnetic head that records and reproduces information on the data track, and W ₂ is the core. It indicates the width, and each size has a relation that W ₁ ≈ 2T ≈ 2W ₂ . 1 to 7 are boundary lines of the servo tracks, which are apparently arranged so as to coincide with the center lines of the data tracks # 1 to # 7, respectively.

Further, the core 51 of the servo head and the core 52 of the magnetic head are both supported by the same actuator (not shown), and are structured to be integrally driven on the servo track or the data track.

A to C are positioning signal demodulation indexes that divide the circumference of the servo track into several thousand, and form, for example, two magnetization patterns in the radial direction. There are four regions for writing the phase signals between the adjacent positioning indexes, which are called 01, 02, E1 and E2, respectively. In the phase signal writing areas 01, 02, E1, and E2, as shown in the figure, the magnetization patterns of two tracks in length are regularly arranged by shifting by one track, and the writing of the phase signals in the same radial direction is performed. Area 0
Magnetization patterns are arranged every two tracks on 1,02, E1, and E2. The patterns of the same track have the same shape.

In the figure, the symbol Pn indicates a reference magnetization mark that is a starting point at one position on each circumference of each servo track, the subscript n indicates the boundary line number of each servo track, and is arranged on the same radius line of the magnetic disk surface. It is one of the positioning indexes A to C and the like formed on the servo track.

For example, when the servo head core 51 moves from A to B with the boundary line 2 as the center position on the servo track thus formed, the servo head core passing through one of 02 and E2.
51 outputs a pulse waveform of the same signal level, and when the center position is deviated, the signal level of the pulse waveform at the positions of 02 and E2 can be varied in proportion to the length of the magnetization pattern traversed by the core 51. Therefore, by controlling so that 02 = E2, the servo head can seek the boundary line 2 of the servo track, that is, the data track # 2, by the core 52 of the magnetic head.

Similarly, if 01 = E1 is controlled, the boundary 52 of the servo track, that is, the data track # 3 can be sought by the core 52 of the magnetic head.

As described above, the positioning means uses the two-phase servo signal to position the head by selecting the phase signal that can detect 01 = E1 and 02 = E2. Although the circuit configuration for selecting the two transfer servo signals is a known technique, description thereof will be omitted. However, the sector pattern formed by the magnetic pattern is decoded by using a decoding circuit and a microprocessor or the like to convert the position information. .

FIG. 6 shows the principle of the spiral servo track writing means. At the time of servo track writing, one reference magnetization mark P ₁ and a servo signal writing reference clock Ck are prepared for _one track. Assuming that the number of pulses of the servo signal writing reference clock Ck in one round is n and one track width is T, the target position signal Xm is ± m when the number of pulses of the reference clock Ck is counted and m.
× T / n correction (whether positive or negative spread spiral clockwise,
Select according to whether it spreads counterclockwise).

FIG. 7 shows a block diagram of a spiral track servo track writing means. In the figure, a counter 62 synchronizes the reference magnetization mark P ₁ with the reference clock signal Ck by a circuit 61.
To enter. Then, the output of the counter 62 and the initial target position signal X are combined by a combining circuit 63 to calculate a positioning target position signal Xm.

The count value m is cleared in the reference magnetization mark Pn, counted within one cycle, and the initial target position signal X is set for each track. Ck may be counted continuously. The servo writing pattern is switched by the reference magnetization mark Pn.

In the conventional magnetic disk device, since the servo tracks are concentrically formed, in recording / reproducing data continuously recorded over multiple tracks, the time required for head movement and settling is set each time the head moves one track. In addition, since the servo index portion is detected, the time corresponding to one rotation of the spindle is wasted.

[Problems to be solved by the invention]

If one of the ways to overcome this problem is to simply form the servo track in a spiral pattern, and if the servo head continues to seek the servo track, the disadvantage of jumping out of the area at the end of the servo track will occur. However, there was a drawback that extra control was required for that.

In view of the above-mentioned conventional drawbacks, the present invention relates to a servo signal recording / reproducing system in which spiral servo tracks are connected to start and end concentric servo tracks and switching control is performed between the spiral servo tracks and the concentric servo tracks. The purpose is to provide.

[Means for solving problems]

The servo track of the magnetic disk is formed in a spiral shape, and each of the reference magnetization marks Pn for switching to the next phase mode only once in one turn on the spiral servo track is provided on the same radial line of the magnetic disk, and the reference In a servo pattern formed by recording a two-phase servo signal with the magnetization mark Pn as the starting point of the one round, the start end Ps and the end Pe of the spiral servo track are aligned on the same radial line, and the two-phase servo signal Several tracks of concentric servo tracks continuously having two-phase servo signals of the same format are respectively provided at the start end Ps and the end end.
When the magnetic head for detecting the two-phase servo signal is formed by connecting to the Pe so that the developed view of one track of the connecting portion becomes a triangular shape, the reference magnetic mark at the start end Ps or the end Pe. It is achieved by providing the servo signal recording / reproducing system of the present invention, characterized in that the tracking control of the phase mode of the spiral servo track or the concentric circular servo track is switched by detecting.

[Action]

That is, according to the present invention, in a magnetic disk device, a servo track is formed in a spiral shape by using a phase servo signal, and concentric circular servo tracks are connected to a start end and an end thereof, and a spiral shape is formed at the connection point. Reference magnetization mark for switching each concentric servo track
Provide Ps (for start edge) and reference magnetization mark Pe (for end edge) 2
The magnetic head that detects the phase signal has the reference magnetization mark Ps.
Alternatively, the tracking control of the phase mode of the spiral servo track or concentric servo track is switched by detecting Pe, and the servo signal can be continuously recorded and reproduced at high speed over several tracks in the spiral servo track. In addition, in the concentric servo track, the head can be maintained in a fixed state by facing the disk radial direction.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a signal magnetization pattern development view of the servo track of the present invention, and FIG. 2 shows a signal reproduction waveform thereof. In addition,
To facilitate understanding of the configuration and operation, the same parts as those in the previous figure are denoted by the same reference numerals and the number of servo patterns in the circumferential direction is reduced.

In FIG. 1, a region B is a spiral servo track, a region A is a concentric servo track, and a region line 12-12 of the region B indicates a connecting portion between the start end of the region B and the region A.
Further, the region C is also a concentric servo track, and the boundary line 34-34 with the region B indicates the connecting portion between the end of the region B and the region C. The numbers on the left and right in the figure are boundary line numbers when the servo tracks are cut in the radial direction, and the same numbers on the left and right correspond to the servo tracks as in FIG.

The start point Ps and the end point that are the branch points of the concentric circle part and the spiral part
Both Pe are provided so as to coincide with each other on the same radial line of the magnetic disk on which the reference magnetization mark Pn serving as the starting point of each servo track is arranged. That is, the reference magnetization mark P ₁₂ located on the boundary line 12-12 coincides with the position of the start end Ps, and the reference magnetization mark P ₃₄ located on the boundary line 34-34 coincides with the position of the end end Ps. In the writing areas 01, 02, E1, E2 of the phase signal, the same magnetization pattern of the two-phase servo signal as in FIG. 5 is recorded.

Servo positioning control may be performed by a known method within the concentric servo track portion (areas A and C) or within the spiral servo track portion (area B).

There are two types of position control on the boundary between the concentric circle part and the spiral part. That is, in the control of the portion that shifts from the first area A to the area B, the output signal level of the core 51 of the servo head (see FIG. 2) is first detected by detecting the reference magnetization mark Pe = P ₁₁ of the concentric servo track. ) Is controlled so that 01 = E1, and the servo head is fixed to the concentric circle portion of the track boundary line 12-12 (see FIG. 2). Then the starting point Ps = P
_{When the} phase selection is switched so that the output signal level of the core 51 becomes 02 = E2 upon detection of ₁₂ (reference magnetization mark), the servo is generated in the spiral part of the boundary line 12-13 (see FIG. 2). The head starts moving.

At the portion where the second region B is shifted to the region C, the output signal level of the core 51 is controlled to 01 = E1 at the spiral boundary line 32-33 (see FIG. 2), and then the termination Pe = P. ₃₄
If the phase selection is switched so that the output signal level of the core 51 becomes 02 = E2 upon detection of the (reference magnetization mark), the boundary line
The servo head begins to move to the concentric circles 34-34 (see Fig. 2).

The determination as to whether the position of the servo magnetic head is on the concentric servo track or on the spiral servo track can be easily recognized by decoding the output of the magnetic head by a decoder circuit (not shown). , Starting point Ps
Alternatively, the detection of the end Pe may be performed by detection means including decoding of the sector index patterns before and after the end Pe. In addition, when a concentric circle portion is provided in an arbitrary spiral area, it suffices to connect the changing portion of area B → area C (area A) → area B, and to detect the pulse pattern (01,02, E).
1, E2) is not limited to the example shown.

In this embodiment, by using the spiral servo track, data can be read / written over several tracks without waiting for track movement. In order to make the effect stronger, it is better to operate all the data heads in the actuator at the same time, and wait for the data to be in a parallel state until the head section. For example, in the case of 8-bit data, bit 1 corresponds to data head 1 and bit 2 corresponds to data head 2. According to this, it is considered that effects such as image storage are exhibited.

In addition, by providing the concentric circle regions in a linked manner, a region in which the head can be fixed in the radial direction is provided, and particularly in the spiral portion, it jumps out of the servo track region, but this can be prevented. it can. Moreover, since the phase selection is used for the switching, the control is simple.

〔The invention's effect〕

As described above in detail, according to the servo signal recording / reproducing method of the present invention, by forming the servo tracks in a spiral shape, there is an effect that data over a large number of tracks can be recorded / reproduced in a shorter time than in the conventional case, and concentric circles can be formed. By interposing the servo track, the head fixing region in the radial direction can be provided.

[Brief description of drawings]

1 is a development view of a signal magnetization pattern of a servo track of the present invention, FIG. 2 is a signal reproduction waveform of FIG. 1, FIG. 3 is a schematic view and development view of a conventional concentric servo track surface, and FIG. Is a schematic view of a conventional spiral servo track surface and its development view. FIG. 5 is a relative positional relationship diagram between the magnetization pattern of a two-phase servo signal recorded on the servo track surface and the corresponding track position on the data surface. FIG. 6 is a diagram for explaining the principle of the spiral servo track writing means, and FIG. 7 is a block diagram of the spiral servo track writing means. In the figure, areas A and C are concentric servo tracks, area B is a spiral servo track, 01, 02, E1, E2 are 2
The phase signal writing area of the phase servo signal is shown respectively.

Claims (1)

[Claims] 1. A servo track of a magnetic disk is formed in a spiral shape, and each reference magnetization mark Pn for switching to the next phase mode at only one position on the circumference of the spiral servo track is on the same radial line of the magnetic disk. In preparation for this, the reference magnetization mark Pn is used as the starting point of the one round.
In the servo pattern that records the phase servo signal, the start (Ps) and end (Pe) of the spiral servo track
And are aligned on the same radius line, and several tracks of concentric circular servo tracks continuously having a two-phase servo signal of the same format as the two-phase servo signal are set as the start end (Ps) and the end (Pe), respectively. A magnetic head that forms a development view of one track of the connecting portion in a triangular shape by connecting the magnetic heads and detects the two-phase servo signal is
A servo signal recording / reproducing method characterized in that the tracking control of the phase mode of the spiral servo track or the concentric servo track is switched by detecting the reference magnetization mark at the start end (Ps) or the end (Pe). .