JPH0721540A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To miniaturize the disk device and to reduce the price by deciding whether a magnetic head is deviated from a target track or not and changing the contents of position error signal preparation processing. CONSTITUTION:It is identified and judged whether position code information (E-H) showing the radial position of a magnetic head 3 on a magnetic disk 2 is equal with the last position or not and by detecting that the position code information (E-H) is equal with the last time, it is decided that the head 3 is not deviated from the target track of the disk 2. At a CPU 20, a position error signal is prepared based on position error signals (J and L). On the other hand, by detecting that the information (E-H) is different from the last time, it is decided that the head 3 is deviated from the target track of the disk 2. At this time, the position error signal is prepared based on both the information (E-H) and the signals (J and L) provided from a position code information detecting means and a position error information detecting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device which is an auxiliary storage device of a personal computer, and more particularly, to servo information necessary for tracking operation and seek operation.
The present invention relates to an embedded servo type magnetic disk device which is embedded in a data surface for recording data to increase the ratio of a data area on the disk surface of the entire magnetic disk device.

[0002]

2. Description of the Related Art With the recent development of computers, high-speed access to external storage devices such as magnetic disk devices,
As the demand for higher capacity, smaller size, and lower price increases,
In the magnetic disk device, the conventional dedicated head and disk surface
Embedded servo method that increases the ratio of the data area on the disk surface of the entire magnetic disk drive by embedding the servo information required for tracking operation and seek operation that occupied the (servo surface) in the data surface for recording data. Is common. FIG. 4 is a diagram showing a configuration example of an embedded servo system in a conventional magnetic disk device. Further, FIG. 5 is a time chart showing the operating states of the CPU (1) and the CPU (2) of the magnetic disk device having the conventional configuration in the case where the read / write operation is continuously performed without interposing the seek operation, FIG. 6 is a position error signal generation flowchart, and FIG. 7 is a schematic diagram showing a structural example of position code information and position error information in the servo area. In FIG. 7, a portion A is a data area in which data to be read / written exists, which corresponds to the data area 33 in FIG. 5, and B to M indicate the radial direction of the magnetic head 3 on the magnetic disk 2. Position code information indicating the position
(E-H) and position error information (J, J indicating the amount of deviation of the magnetic head 3 from the target track center line on the magnetic disk 2).
L) is included in the servo area and is represented by the servo area 34 in FIG. In FIG. 4, 1 is a spindle motor, 2
Is a magnetic disk, 3 is a magnetic head, 4 is a voice coil motor (hereinafter abbreviated as VCM), 5 is a pivot, 7 is a read / write amplifier, 9 is a pulse detector / ENDEC,
14 is a filter, 17 is an interface / hard disk controller, 19 is a system bus, 21 is a CPU
(2), 22 is RAM, 23 is ROM, 25 is a spindle driver, 28 is a servo controller, 30 is a VCM driver, 32 is a CPU (1), and other symbols are connection lines for connecting the respective components to each other. is there.

The operation of the magnetic disk device will be briefly described below with reference to FIGS. 4, 5, 6 and 7. The magnetic disk 2 receives a command from the CPU (1) 32 via the connection line 24, and is rotated at a constant speed by the spindle motor 1 driven by the operating spindle driver 25 via the connection line 26. On the other hand, the magnetic head 3 which is attached to the other end of the VCM 4 which can be swiveled around the pivot 5 and is pressed against the surface of the magnetic disk 2 with a constant weight, as described above, starts when the magnetic disk 2 starts to rotate. The surface of the magnetic disk 2 is slightly lifted from the surface of the magnetic disk 2, and the magnetic disk 2 can be smoothly moved around the pivot 5 in the radial direction. Within a data area (not shown) on the magnetic disk 2, there are a plurality of concentric tracks centered on the rotation center axis of the spindle motor 1, and there are dozens of tracks at equal angular intervals in the circumferential direction. There is a servo area (not shown), and the servo area is arranged so that the reproduction signals have the same phase between adjacent tracks as illustrated in FIG. Position code information of a track and position error information for positioning on an arbitrary track are written in advance in the servo area, and the magnetic head 3 moves directly above the servo area at a constant time interval as the magnetic disk 2 rotates. It is possible to obtain the position code information and the position error information each time the vehicle passes. On the other hand, the magnetic head 3 can move to an arbitrary position in the data area by turning around the pivot 5, and can position an arbitrary track by position error information in the servo area.

Before describing the data writing / reading operation, the reading of the position code information and the position error information, the tracking operation, and the seek operation will be described first. As described above, an arbitrary track in the data area has several tens of servo areas in one rotation. Magnetic head 3
Passes through the servo area, read / write amplifier 7, connection line 8, pulse detector / ENDEC 9, connection line 1
2. A unique reproduction signal pattern is transmitted to the servo controller 28 via the filter 14, the connection line 16, and the servo controller 28 decodes the position code information and the position error information and transmits the sample / hold operation. To start. The position code information and samples / decoded by the servo controller 28
The held position error information is transmitted to the CPU (1) 32 via the system bus 19 and the connection line 27, respectively.
The system bus 19 has an interface with a host system such as a ROM 23, a personal computer, or the like, which stores and holds the processing procedure of the CPU (1) 32, the servo controller 28, and the CPU (1) 32 in the form of microcode. Also connected are a CPU (2) 21, which has a function of managing various information inside the magnetic disk 2, an interface / hard disk controller 17, and a RAM 22 which is used as a buffer when interfacing with a host system. The CPU (1) 32 sends a VCM drive command, which will be described later, to the VC (via the connection line 29) according to the status of the tracking / seek operation.
The command value is written in the D / A converter inside the servo controller 28 so as to be given to the M driver 30. First, when tracking to an arbitrary track, the CPU (1) 32 uses the position error information (J, J in FIG. 7) in the servo area 34 of FIG.
Based on L), the position error signal which is the amount of deviation from the center line of the target track is calculated, position compensation calculation processing is performed so as to stably generate centripetal force to the center line of the target track, and the processing result is servo-processed. -Write as a command value in the D / A converter inside the controller 28. The command value converted into an analog amount by the D / A converter drives the VCM 4 so that the magnetic head 3 located at the other end across the pivot 5 is located directly above the target track. In this way C
The PU (1) 32 realizes tracking closed loop control of the magnetic head 3 with respect to a target track on the magnetic disk 2.
FIG. 6 is a flowchart briefly describing the procedure for calculating the position error signal based on the position error information (J, L in FIG. 7). This calculation is performed by the CPU (1) 32 to process the data in FIG. S11, S at the timing indicated by
12 and S13 are executed in this order to calculate the position error signal. Next, in a seek operation for moving from an arbitrary track to another target track, first, the CPU (1) 32 calculates the temporal difference of the position code information of the servo area 34 obtained at a constant time interval. The average moving speed obtained is used as the moving speed of the magnetic head 3 and is used as a feedback signal for seek closed loop control. The CPU (1) 32 servos the amount of error between the speed reference value obtained by searching the table of speed reference values stored in the ROM 23 with the number of remaining tracks up to the target track as an index for table search and the moving speed. ·controller
28. The write VCM 4 is driven to the D / A converter in the inside, and seek closed loop control is realized so that the magnetic head 3 located at the other end across the pivot 5 is moved at a speed according to a speed reference value table. Such a seek operation command is normally given from the host system as a command to the CPU (2) 21 via the host interface 18 and the interface / hard disk controller 17,
After the address calculation and the command parameters are checked, the seek operation transmitted to the CPU (1) 32 is executed as described above.

Next, an outline of the read / write operation will be described with reference to FIGS. 4, 5, 6 and 7. Lead /
Similarly to the seek operation instruction, the write operation instruction is normally given from the host system to the CPU (2) 21 via the host interface 18 and the interface / hard disk controller 17 as a command. CPU (2) 21
Check the address code and command parameters, and then position code information, that is, cylinder number,
The head number is transmitted to the CPU (1) 32, and the seek operation of moving the magnetic head 3 to the target position on the magnetic disk 2 is instructed to start, and the interface / hard disk controller 17 is read / write data. Various parameters necessary for this are set and prepared for the read / write operation after the seek operation is completed. When the seek operation for moving the magnetic head 3 to the target position on the magnetic disk 2 is completed, the CPU (1) 32 starts the tracking operation described above, and the CPU (2) 21 reads and reads data from the magnetic disk 2. Send to host system / host
Various setting operations for the interface / hard disk controller 17 necessary for receiving data from the system and writing on the magnetic disk 2 are executed at the timing shown by the servo area 34 in FIG.
As described above, the read / write operation in the embedded servo type magnetic disk device is executed by the joint work of the two CPUs because of time constraints.

[0006]

However, as described in the above-mentioned prior art, as the demand for miniaturization and cost reduction of the magnetic disk device increases, the area occupied by the control board of the device becomes smaller. The number of parts that can be mounted on the control board is naturally limited. However, in the magnetic disk device having the configuration described so far, one CPU is required to position the magnetic head at an arbitrary position on the magnetic disk, and the read / write operation is controlled for the magnetic disk. To the above C
A CPU is required separately from the PU. That is, the control board of the magnetic disk requires two CPUs, and the area occupied by the control board is not only an obstacle to the downsizing of the device, but also a disadvantageous factor in reducing the cost of the device. Has become. The present invention has been made in view of the above circumstances, and provides a compact and low-priced magnetic disk device by removing obstacles to downsizing and cost reduction of a control board and thus a magnetic disk device in an embedded servo type magnetic disk device. The purpose is to do.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems and to provide an object of providing a small-sized and low-priced magnetic disk drive, the present invention is directed to a position error signal generating process from a target track on a magnetic disk. A normal state (on-track state) is added by determining whether the head is off (off-track) and changing the content of the position error signal creation process depending on whether it is off-track or not. It is possible to simplify the position error signal creation processing in step S3.
This makes it possible to time-divisionally process the position error signal creation processing, which has conventionally been performed by occupying one CPU, in the CPU for controlling the read / write operation.

[0008]

Therefore, according to the present invention, one conventional CP
The position error signal generation processing that has been performed by occupying U can be time-divisionally processed by the CPU for controlling the read / write operation, and the control board and thus the magnetic disk in the embedded servo type magnetic disk device can be processed. It is possible to eliminate obstacles to downsizing and cost reduction of a disk device, and it is possible to provide a compact and low-priced magnetic disk device.

[0009]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3 and 7. FIG. 1 is a diagram showing a configuration example of an embedded servo system in a magnetic disk device of the present invention. Further, FIG. 2 is a time chart showing the operating condition of the CPU 20 of the magnetic disk device having a configuration in which the read / write operation is continuously performed without sandwiching the seek operation, and FIG. 3 is a position error signal generation flowchart. ,
FIG. 7 is a schematic diagram showing a structural example of the position code information and the position error information of the servo area. In FIG. 7, a portion A is a data area in which data to be read / written is present, which corresponds to the data area 33 in FIG.
Is position code information (E to H) and position error information (J, L)
2, which is represented by a servo area 34 in FIG.

In FIG. 1, the same reference numerals as those in FIG. 4 indicate the same functions, and the description thereof will be omitted. Hereinafter, the difference from the conventional example will be mainly described. In FIG. 1, a CPU 20 is a CPU (1) 32 and a CPU (2) 21 2 in the configuration diagram of the conventional magnetic disk device according to FIG. 4 described in the section of the prior art.
It is a CPU that performs processing of one CPU. Figure 2 is the CP
FIG. 3 is a time chart for explaining the processing contents of U32, and FIG. 3 is a flowchart for improving the position error signal generation processing at the time of read / write operation, which had a problem in processing time in the conventional example.

Here, FIG. 3 will be briefly described. Figure 3
, The position code information (E to H) shown at the position of the magnetic head 3 on the magnetic disk 2 in the radial direction is identified and judged, and the magnetic head 3 determines the target track of the magnetic disk 2. If it is detected that the position code information (E to H) is the same as the previous time (S1-YES), the CPU 20 detects the position error signal which is information obtained from the position error information detecting means. (J, L)
A position error signal is created based on the above (S5), and on the other hand, the fact that the magnetic head 3 is displaced from the target track of the magnetic disk 2 means that the position code information (E to H) differs from the position code information of the previous eye. When detected, (S1-NO), position code information detecting means and position code information (E-H) and position error signal obtained from the position error information detecting means.
A position error signal is created based on both information (J, L) (S2, S3, S4). In the normal state of the tracking operation in which the magnetic head 3 follows the target track on the magnetic disk 2, the magnetic disk 3 does not deviate from the target track of the magnetic disk 2. Therefore, the judgment means of S1 is added to By simplifying the position error signal generation process of step S5, the position error signal generation process time in the normal state can be shortened. When a read / write operation command given from the host system via the host interface 18 and the interface / hard disk controller 17 as a command is received, the CP
U20 first performs a seek operation for moving the magnetic head 3 to a target position on the magnetic disk 2 in the procedure as described above. When the seek operation for moving the magnetic head 3 to the target position on the magnetic disk 2 is completed, the CPU 20 creates a position error signal according to the above-described processing procedure shown in FIG. Read data from and send to host system /
Various setting operations for the interface / hard disk controller 17 necessary for receiving data from the host system and writing on the magnetic disk 2 are executed at the timing shown by the servo area 34 in FIG. As a result, the position error signal creation processing, which was conventionally performed by occupying one CPU, can be performed in a time-division manner by the CPU that has the function of managing various information inside the magnetic disk and the interface with the host system. Becomes

[0012]

According to the present invention, as is apparent from the above embodiment, the circuit of the control board, which has been an obstacle to the miniaturization and cost reduction of the magnetic disk device, can be constructed by one CPU. Therefore, it is possible to provide a small-sized and low-priced magnetic disk device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a time chart of the magnetic disk device according to the embodiment of the present invention.

FIG. 3 is a flow chart for creating a position error signal according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional magnetic disk device.

FIG. 5 is a time chart of a conventional magnetic disk device.

FIG. 6 is a flowchart of conventional position error signal generation.

FIG. 7 shows an example of an embedded servo type sabot pattern.

[Explanation of symbols]

1 ... Spindle motor, 2 ... Magnetic disk, 3 ...
Magnetic head, 4 ... VCM, 5 ... Pivot, 6,
8, 10, 11, 12, 13, 15, 15, 16, 24, 26, 27, 29, 31 ... Connection line, 7 ... Read / write amplifier, 9 ... Pulse detector / ENDEC, 14 ... Filter, 17 ... Interface / Hard disk controller, 18 ... Host interface, 19 ... System bus, 20 ... CPU,
21 ... CPU (2), 22 ... RAM, 23 ... ROM, 25
… Spindle driver, 28… Servo controller,
30 ... VCM driver, 32 ... CPU (1), 33 ... Data area, 34 ... Servo area, 35 ... Data processing, 36
... Servo processing, A ... Data area, B ... AGC burst section, C ... DC erase section, D ... Sync bit,
E, F, G, H ... Track code, I, K, M ... Pad section, J, K ... Tracking burst section, N ... Track center, T _P ... Track pitch, G _W ... Track width.

Claims (2)

[Claims] 1. A magnetic head for detecting position code information on a magnetic disk, position error information detecting means for detecting a deviation amount from a target track center line on the magnetic disk, and the position code information. The position information obtained from the means is means for determining whether or not the magnetic head is displaced from a target track on the magnetic disk, and the determining means causes the magnetic head to be displaced from the target track on the magnetic disk. When it is detected that the position error signal is not detected, a position error signal is created based on the information obtained from the position error information detecting means, and the magnetic head is controlled so as to follow the target track center line on the magnetic disk. When the judgment means detects that the magnetic head is displaced from the target track of the magnetic disk, A position error signal is generated based on the information obtained by the position code information detecting means and the position error information detecting means, and the magnetic head is controlled so as to follow the target track center line on the magnetic disk. Magnetic disk device characterized by. 2. A simplified position error signal creation process in a normal state is time-divisionally performed by a CPU having an interface with a host system and a function of managing various information inside a magnetic disk. The magnetic disk drive according to claim 1.