JPS6391882A - Magnetic recorder - Google Patents

Abstract

PURPOSE:To improve the accuracy by deriving a correction value derived from position information on a data face with regard to all data heads, superposing this correction value on a position signal obtained from position information on a servo-face, and positioning the head. CONSTITUTION:A second position information is read out by each data head 17 and the head output amplitude of this position information becomes a digital value by a peak holding circuit and an A/D converter and sent to a CPU 22. The CPU detects the direction of deflection and the deflected position of both data heads, and stores them in a RAM. At the time of positioning a data head 17 to a data track, the deflection of the data head 17 is corrected by superposing the deflected quantity stored in the RAM, to a position signal detected from a first position information on a servo-face. This detection is executed at a prescribed time interval and the storage in the RAM is updated. Accordingly, as for the variation of an environmental temperature, a deflection generated due to the shift of a mechanism part, etc., is obviated together with the updating of the correction quantity in the RAM.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application in Industry] The present invention is directed to an improvement in a method for determining the head position 1η of a magnetic recording device.

[Conventional technology]

The magnetic recording device is a magnetic disk (hereinafter referred to as a disk).
A head (hereinafter referred to as a head) is used to record and reproduce information on the disk, and the head is fixed to a mechanism section that moves and positions the head. A large number of concentric 1'-small recording areas called tracks are provided on the disk, and by moving the head over these tracks, information is recorded and reproduced between the disk and the hennode.

FIG. 5 shows a mechanical section of a conventional magnetic recording device.

5il of disc! One surface 32 of the recording surfaces is a dedicated surface (hereinafter referred to as a servo surface) for recording position information. The remaining surface 34 is the surface on which data is recorded (hereinafter referred to as the data surface). The disk is fixed to a main shaft motor 35 and rotates. A head 16 (
A head 17 (hereinafter referred to as a servo head) arranged in correspondence with the data surface (hereinafter referred to as a data head) is both fixed to a positioning mechanism 33 and can be moved in the radial direction of the disk by a linear motor 19. °
- Place the head on the track (hereinafter referred to as servo track) where the position information on the servo surface is recorded. When T is determined, the circular locus on the data surface where the data head is positioned is used as a trunk (hereinafter referred to as a data track) for recording data. Then, by monitoring the device information detected from the servo head and controlling the positioning mechanism so that the deviation between that position and the target position is minimized at '1δ°, the servo head is positioned on the target servo track. , the data head is secondarily positioned on the target data track.

This positioning method can accurately position one head on the servo track, but the
Additionally, thermal expansion and mounting of the disk and head support mechanisms cannot compensate for positioning errors between the target data track and the data head caused by changes in accuracy over time and the like.

Therefore, in order to solve this problem, we developed Japanese Unexamined Patent Publication No. 511 (10)
As described in 03, the correction value obtained from the second position signal of the data track "2" is added to the device signal detected from the first position information of the servo surface as follows:
A method was devised in which the data head was positioned on the data track at a single mark.

[Problem that the invention seeks to solve]

As described above, in the conventional positioning method using a servo surface, the data head cannot necessarily be accurately positioned on the target data track.

In order to overcome this drawback, it is necessary to record position information on each data surface as well.
According to method 3, each time the head is switched, the position information on the data track is rotated to the position of the data head (
Location information cannot be obtained until It is possible to reduce waiting time by placing a large number of position information on the data track in one rotation, but
This time, as can be easily imagined, the 1 m area occupied by positional information on the I-event plane becomes larger, significantly reducing the efficiency of use of the data plane. Furthermore, since data and position information coexist on the same track by dividing the area, there is no flexibility in the size of the hikta. In other words, the smallest continuous data block [one sector is called a sector, but a sector with a size larger than the interval from one position information on a data track to the next position information has position information that is not data in between. It cannot be taken because it is included. Since the required sector size varies depending on the system in which the magnetic recording device 1i' is used, fixing the sector size is extremely inconvenient because it narrows the scope of application of the magnetic recording device 15'. Furthermore, it takes a great deal of time to record position information on all data tracks, reducing the productivity of the magnetic recording device.

The present invention provides a magnetic recording device that improves the above-mentioned drawbacks.
The porpose is to do.

Means for Solving Problem C] The present invention provides a disk surface for a servo on which first position information used as a control signal for positioning a data head on a target data track is recorded, and data and first position information. 2
a data disk surface on which positional information is recorded; a servo head disposed in correspondence with the servo disk surface; a data head disposed in correspondence with the data disk surface; In a magnetic recording device comprising a control unit that controls the positioning of the data 2) on a target data track based on the first and second position information, the second position t'+' is informed; The second position information is recorded on a track different from the data track, and the second position information is recorded on a track on the servo disk surface that corresponds to the track on which the second position information is recorded. is included along with the first position information or specific information indicating that it is on the recorded track;
n' with respect to the track where the second position information is recorded.
11 based on the device signal detected from the first position information
After performing proper positioning and confirming the specific information, the positional deviation between the data head and the y'-ta track is detected for each data head by referring to the second position information written in t'jl. The position deviation 7.1 is stored and superimposed on the device signal detected from the first position information to position each data head.

〔Example〕

The present invention will be described in detail below with reference to Examples. 1st
Figure a shows the magnetization pattern recorded on the servo surface. This is a magnetization pattern that generally corresponds to the well-known Modified Guibit. The dashed-dotted line in the figure shows the center of the track, and the solid line shows the magnetization reversal. The periodicity of

That is, when the tracks are numbered sequentially, there are 4 gi magnetization patterns of ns n+1, n+2, and n+3, where n is an integer. When the gap l of the servo head is at the position shown in the figure and a track runs under it, the read waveform of the magnetic head will be as shown in the 11th RIC. The magnetization pattern also has periodicity with respect to the track running direction, and this fundamental period is the servo cell 2. Therefore, the readout waveform shown in FIG. 3C is also periodically repeated. In one servo cell, there are four types of magnetization reversal, which are indicated by broken lines in the figure, and these are the first position information in this embodiment. The height of vl: peak 3.4.5 of the protruding waveform caused by four types of magnetization reversal, and the height of G are the gears of the servo head, 1
- Depends on which track the knob is on. When the servo head's v-tube is at position 1, the peak at 6 does not occur. To position the servo head on the n+1 track, the position of the servo head is controlled so that peak 3 and peak 4 are at the same height. Since the magnetization reversal that causes peak 7.8 is normally written continuously across all tracks, peak 7.8 exists in the readout waveform of any track, but the peak 7.8 in the figure is 00. Since this magnetization reversal is not present at this position, peak 7.8 is missing at this position. In other words, the readout waveform when the servo head is at position 10 is shown in FIG. 1d, but no peak appears at position 11. The magnetization reversal that causes peaks 7 and 8 is called a sync pattern, but by missing the sync pattern at specific intervals in a specific track, it is possible to detect that the servo head is positioned on this track. Can be done.

In this way, when the servo head is positioned on a servo track that can be identified by specific information with a missing sync pattern, a magnetization pattern as shown in Figure 2 is recorded on the data track on the data surface where the data head is located. . In FIG. 2, small arrows indicate the direction of magnetization. 12
is the center line of this track, and the magnetization patterns 13 and 14 are deviated from the center of this track by the same amount ff1J toward the inner circumference and the outer circumference, respectively. If the amplitudes of the read waveform of the magnetization pattern 13 and the read waveform of the magnetization pattern 14 are equal, it means that the gap 15 of the data head is set to this track by 1δ.

The mechanical section of the magnetic recording apparatus of this embodiment is the same as that shown in FIG. A block diagram showing circuit detection is not shown in FIG. The servo circuit 18 is a circuit that controls the linear motor 18 so that the servo head 16 is positioned on the first servo track based on the first position information read from the servo head 1G. It is used in magnetic recording devices that strike a surface. However, the servo circuit of this embodiment receives the digital signal output from C1) U22 and controls the servo head by the amount corresponding to this digital signal.
It can be offset from a single servo truck. Since the servo circuit has traditionally had the function of making the servo head follow the target position, in order to achieve the above-mentioned function 1, it is only necessary to add an adder circuit using an A converter and an operational amplifier to offset the target position. The recording and reproducing control circuit 20 converts the output of the data head 17 into digital data and transmits it to the interface circuit 21.
It is also a circuit that converts the code of data transmitted from the host system via the interface circuit 21 and sends it to the data head. Further, the recording/reproducing circuit is located at the second position ti? in FIG. 2 mentioned above. Read the information and detect the amplitude. The interface circuit transfers data and commands to and from the host system.

Furthermore, the servo circuit includes a circuit (not shown in FIG. 4) for detecting a lack of sync pulses, and can detect the above-mentioned specific information. In FIG. 71 [Δ], the output waveform of the servo head as shown at 30 in FIG. 4 (1', ) (b) is applied to the signal line 23. A voltage at a level shown in 31 in the figure is applied to the signal line 24, and the output of the comparator 25 is as shown in C in the figure. 2G is a monostable multivibrator, and the input of C in the figure produces the output of (1) in the figure.The time when the output of the monostable multivibrator 26 becomes high is two pulses of the sink butter
A is shorter than the interval between the four peaks that are the first position information. Therefore, only the subsequent pulses of the sync butter are outputted from the AND circuit 28, as shown in FIG. 10. This output is input to the monostable multi-by-break 29. The monostable multi-by break is retriggerable, and the time it goes high is set to be slightly longer than the time for one servo cell.Therefore, the output of the mono-stable multi-by break 20 becomes low level only when the sync pulse is missing.

A method for positioning the data head in the magnetic recording device of this embodiment will be described. First, using the first position information written on the servo surface, the head is moved and positioned to the track containing the aforementioned specific information in the same manner as in conventional magnetic recording devices. Next, after the specific information is confirmed by the circuit shown in FIG. 4, the '2nd position tn information is read out by each data head. The head output horn amplitude of the position information shown in FIGS. 13 and 14 is converted into a digital value by the peak hold circuit and the AI converter and sent to the CPU. C
The PU detects the direction of deviation of the data head based on the magnitude of the two amplitudes, and detects the deviation position of the data head based on the ratio of the two amplitudes, and stores this in the RAM. To position the data head on the data track, the deviation position recorded in the RAM is added to the device signal detected from the first position information on the servo surface to correct the deviation of the data head. .

” - The above-mentioned offset position detection is performed at fixed time intervals! 2 A Note in M? 5 is updated. Therefore, the deviation of the front part caused by changes in environmental temperature, misalignment of mechanical parts, etc.
This problem is resolved when the correction claw in A is updated.

In addition, since the second position information is located on the data surface "2", there is a risk that it will be inadvertently erased by the data head that cuts the old data t-11m. However, in the magnetic recording device of this embodiment, the specific information A hardware function is added to prohibit writing of the data head when detected, so there is no need to worry about the second position information being erased.

〔Effect of the invention〕

As described above, according to the present invention, the correction value obtained from the second position information on the data surface is determined and recorded for all data heads, and this correction value is recorded on the first position information on the servo surface. By positioning the heads with a 4° angle overlap with the position signal obtained from the position information, all heads are positioned correctly on the target data track and with a short distance of 11'. It is possible to position between 1 iu.

Further, since the track where the second position information is old is separated from the data track, the sector size can be changed flexibly and the second position information can be old in a short time.

Furthermore, since the specific information that specifies the second position information is written on the - side, the signal that is not the second position information is ¥J2
This prevents the second location information from being mistaken for the second location information, and prevents the accident of accidentally erasing the second location information.

FIG. 3 is a diagram showing a magnetization button and its readout waveform.

FIG. 2 is a diagram showing magnetization buttons for second position information in the embodiment of the present invention.

FIG. 3 is a block diagram showing circuit detection according to an embodiment of the present invention.

FIG. 4(A) is a circuit for detecting specific information in an embodiment of the present invention, and FIG. 4(n) is a diagram explaining its function.

FIG. 5 is a diagram illustrating a conventional magnetic recording device and a magnetic recording device of the present invention.

Applicants: Seiko Epson Corporation representative PI Patent attorney Tsutomu Mogami and 1 other person r-r/7b
Bodou Figure 1 Figure 5 Figure 3

Claims (1)

[Claims] A servo disk surface on which first position information used as a control signal for positioning the data head on the target data track is recorded, and a data disk surface on which data and second position information are recorded. , a servo head arranged in correspondence with the servo disk surface, a data head arranged in correspondence with the data disk surface, and the data head according to the first and second position information. In a magnetic recording device having a control unit that controls positioning on a target data track, the second position information is recorded on a track different from the data track, and corresponds to the track on which the second position information is recorded. The track on the servo disk surface includes specific information indicating that the data head is on the track on which the second position information is recorded, together with the first position information, and For the track where position information is recorded, positioning is performed appropriately based on the position signal detected from the first position information, and after confirming the specific information, data is determined by referring to the position information in Collection 2. Detecting and storing a positional deviation between the head and the data track for each data head, and positioning each data head by superimposing the positional deviation on a position signal detected from the first position information. A magnetic recording device characterized by: