JPH02278579A - Servo correcting method - Google Patents

Abstract

PURPOSE:To wholly shorten a seek time by executing a head change and updating a servo table concerning the other head when there is an waiting time until a correspondent sector is reached after seeking is completed. CONSTITUTION:After the seeking is completed in accordance with a seek instruction from a host computer 11, when it is judged that there is an enough time until the seeking of the sector to be the next purpose is started, the head is switched to a magnetic head 2 corresponding to a recorded track, which is next read, and servo information are read. Then, the servo table is updated. Thus, when the head change is continuously executed after the sector, which is the purpose, is read, the exact positioning of the head 2 to the recorded track can be executed as it is based on the updated servo table.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a disk drive device, and in particular,
The present invention relates to a servo correction method suitable for an embedded type hard disk drive device with a built-in controller.

[Conventional technology]

There are various types of external storage devices such as computers, but one of them is one with large storage capacity and quick access.
Furthermore, there are hard disk drives that are characterized by their small size. This hard disk drive rotates a magnetic disk in which a magnetic recording layer is formed on the surface of a hard disc made of aluminum or the like at a high speed (for example, about 2600 rpm), and attaches a magnetic head to the surface of the magnetic disk at minute intervals (for example, 0.000 rpm). Signals are written/read in a floating state (approximately .2 to 0.5 μm).

FIG. 2 shows an example of this type of hard disk drive. In FIG. 2, the magnetic head 2 is arranged so as to be accessible to each of the front and back surfaces of a plurality of magnetic disks 1 on which information is recorded. magnetic disk 1
Each of the is a direct drive motor (Direct
Drive Motor (hereinafter referred to as DD motor) 3 rotates as a drive source. Further, the number of magnetic heads 2 is usually twice as many as the number of magnetic disks 1, each of which is integrally attached to a swing arm 4, and a voice coil motor connected to the swing arm 4. (Voice Co11 Motor - hereinafter referred to as VCM) 5 allows movement in the radial direction of the magnetic disk 1.

The magnetic heads 2 are each connected to a node amplifier 6, and servo information etc. from the magnetic heads 2 are amplified.

Further, a servo circuit 7 that performs servo control of the VCM 5 using this servo information and a drive circuit 8 that drives each of the DD motor 3/VCM 5 are provided. Here, the servo circuit 7 is in a relationship to control the drive circuit 8. Drive circuit 8
is provided with a controller 9 for controlling the drive circuit 8 and for enabling data transmission and reception from the magnetic head 2. An external host computer 11 is connected to the controller 9 via a signal line 12. has been done.

The area within the dashed line frame consisting of the reference numerals 1 to 9 constitutes an enhead type hard disk drive (a type in which the controller is integrated into the disk drive).

FIG. 3 is a plan view showing details of the embedded hard disk drive device 10. As shown in the figure, a magnetic head 2 is arranged so that each pair of heads faces each other across each surface of a plurality of (for example, two) magnetic disks J, and drives a swing arm 4 to the outside of the magnetic disk 1. A head drive mechanism 13 is provided. The DD motor 3, swing arm 4, VCMS, and head drive device 13 are attached to a base plate 14 that serves as the base of a casing that holds each member in a sealed state from the outside.

A printed circuit board (not shown) on which a motor drive circuit, a control circuit, etc. are mounted is attached to the base plate 14. The head drive mechanism 13 holds the swing arm 4 and a magnet (not shown), and the swing arm 4
A yoke 15 rotatably supports the coil 1, which is held by the swing arm 4 and is movably disposed within the yoke 15.
G, a bearing part 17 that supports the swing arm 4, a shaft 18 that rotatably fixes the hair ring part 17 to the base plate 14, and a shaft 18 that is connected to the swing arm 4 at one end;
It consists of a regulating arm 19 that holds the PC, and a solenoid 20 that engages the other end of the regulating arm 19 depending on the operation mode to regulate the rotation of the swing arm 4.

The casing that accommodates each of the above-mentioned members includes a base plate 14 and a top cover (not shown), as well as a contact area between the base plate 14 and the top cover and a VCM to maintain airtightness.
A gasket is used in the mounting portion 5, and the shaft portion of the DD motor 3 shown in FIG. 2 is filled with magnetic fluid. Next, the operation of the hard disk drive device with the above configuration will be explained.

This type of disk drive has a recording trunk and VC in advance.
A drive circuit S in which the excitation condition of M5 includes a CPU
It is stored in the internal memory (servo table), and V
The magnetic head 2 can be positioned depending on the driving condition of the CM 5.

Therefore, during operation, the drive circuit 8 selects any recording trunk to be recorded or reproduced in response to a command from the host computer 11.

In the process of tracking this recording trunk, when the gap of the magnetic head 2 is located at a servo sector, a pair of servo signals formed in a staggered manner on the magnetic disk 1 are read out. The read servo signal is amplified by the head amplifier 6, and based on the servo signal output from the head amplifier 6, the drive circuit 8 controls the VCM 5 to move the magnetic head 2 in the radial direction of the magnetic disk 1. . By this control, the gap of the magnetic head 2 is positioned on the center of the track width of the recording trunk. Thereafter, each time a servo signal is detected, the VCM5 is driven as necessary.
The magnetic head 2 is controlled so that it is always located at an appropriate position on the recording track. This allows data to be read or written stably.

By the way, since an embedded type disk drive device has a built-in controller, it is possible to perform interleafing. Interleaf is a system that changes the order of sectors, that is, the skew factor, depending on the difference in transfer time, and aims to shorten the access time to the disk.

[Problem to be solved by the invention]

However, depending on the number of sectors to be read, one magnetic head may not be enough and it may be necessary to change to another magnetic head. In this case, the previous head may not be accurately positioned with respect to the recording trunk. However, if there is a head change, it is necessary to perform servo control again for the recording track where the head change was performed.

Therefore, when a head change is involved, it takes the same amount of time as before. Further, even if a seek is performed based on an instruction from the host computer, it may take a waiting time until the corresponding sector is reached after the seek is completed. Therefore, in conventional seek and servo correction, 2
This means that there are different types of wasted time.

The present invention has been made in view of the actual state of seek and servo correction in the prior art as described above, and an object thereof is to provide a servo correction method that can further shorten the overall access time.

[Means to solve the problem]

The above purpose is to prepare interleave information in advance in a servo correction method for a magnetic disk drive device that has a built-in controller and positions a magnetic head at a predetermined position on a recording track on a magnetic disk by reading servo information assigned to each sector. The interleave information is written in a predetermined position on the magnetic disk, and at least the interleave information is read before a seek command is received from the host computer side. When there is a seek command, the ID of the sector after the seek is completed is read, and the target sector is determined from that ID. The time required to reach the target sector is calculated based on the above interleave information, and when it is determined that the time required to reach the target sector is sufficient, switch to another head, read out the servo information corresponding to the other head, and read the servo information corresponding to the other head. This is accomplished by updating the servo table for the head, then switching to the original head and reading the information written to the desired sector.

[Effect]

According to the above means, even if a seek is performed in response to an instruction from the host computer, if it is determined that there is sufficient waiting time until reaching the corresponding sector after the seek is completed, the head is changed to the head scheduled for the head change. The servo information is read out for the recording track to be recorded by that head, and the servo table for the corresponding recording track for that head is updated. Next, the head is switched to the original head and the information of the target sector is read.

As a result, the next time the head is switched, the head is immediately controlled to an appropriate position and positioning is performed based on the positioning information written in the updated servo table.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a flowchart showing the procedure of servo correction control in a disk drive device according to an embodiment. It should be noted that the hardware configuration of the disk drive device is the same as the disk drive device shown in FIGS. 2 and 3 described above, so a redundant explanation will be omitted.

First, when the disk drive device is turned on, the interleaf information previously recorded on the disk in the form of an interleaf table during logical formatting is read out by the magnetic head 2 (step 21), and the interleaf information that has been read out is read out. , the disk drive is activated (step 22) and following the seek command (step 23).
Perform the seek to its completion (steps 24..25
). During this time, it is determined from the seek command and the interleaf information how many sectors need to be read, and during this series of reads, it is determined whether or not there is a head change. Then, when the above seek is completed, the current ID (Identification) is read out, the target ID that should not be read out first is read out (step 26), and the ID (identification) at the current time is read out (step 26). It is determined whether there is time (step 27).
). In other words, if there is no time, there is no waiting time due to a head change, so there is no need for the processing according to the present invention that utilizes the waiting time.

On the other hand, if there is time to reach the target sector, perform a head change of the head corresponding to the recording trunk to be read next (step 29), read out the servo information of the change destination (step 30), and based on the read servo information. , updates the servo table that stores servo correction information for the target recording track (step 3).
1).

If there is still time left, the process returns to step 29 and repeats the subsequent processes, and if there is no time left, the process moves to the next step 33 (step 32). In step 33, in order to start seeking the target sector, the magnetic head 2 is switched to the original head, and the process moves to step 28, where information recorded in the target sector is read. Note that these processes are performed via the controller 9 and the CPU in the drive circuit 8.

With this processing, when a seek command is received and a seek is completed, if there is enough time to wait for rotation from the read ID to the target sector, the magnetic head 2 is switched to another magnetic head 2, that is, a head change is performed. , reads the positioning information (servo information) for the recording track of the magnetic head whose head was changed, and reads the servo table of the magnetic head and its corresponding recording trunk.
Update based on the read servo information.

In this way, if a head change continues after reading the target sector, the magnetic head 2 can be accurately positioned with respect to the recording track based on the updated servo table.

Therefore, if the servo table is updated during the above-mentioned waiting time for the next magnetic node 2 when the sector length is already specified to have a head change, then the servo correction will be corrected after the head change. A fine track can be achieved without repeating the steps, and the overall seek time can be shortened.

In addition, not only when it is known in advance that a head change will be performed as described above, but also when a head change is not performed, if there is a waiting time, switch to another head and update the servo table. It is also possible to wait for the next head change, and even in this case,
Although not directly, it can contribute to shortening the average seek time.

〔Effect of the invention〕

As is clear from the previous explanation, interleaf information is written in advance to a predetermined location on the magnetic disk, and at least that interleaf information is read before a seek command is received from the host computer, and when a seek command is received, the interleaf information is read out. Read the TD of the sector after completion and write its I
The time required from D to the target sector is calculated based on the above interleaf information, and when it is determined that there is sufficient time required to reach the target sector, the switch is made to another head and the servo information corresponding to that other head is calculated. According to this invention, after reading out the servo table for the other head and updating the servo table for the other head, switching to the original head and reading out the information written in the target sector. Since the head is changed and the servo table is updated in advance, if you return to the original head and then change to the head with the updated servo table, you can immediately achieve fine tracking, reducing wasted time and improving overall performance. Seek time can be reduced.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the procedure of servo correction control in a hard disk drive device according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a control system of a conventional hard disk drive, and FIG. 3 is a plan view showing the internal structure of an example of a hard disk drive. 1... Magnetic disk, 2... Magnetic head, 7... Servo circuit, 8... Drive circuit, 9
. . . Controller, 10 . . . Hard disk drive.

Claims (1)

[Claims] In a servo correction method for a magnetic disk drive device that has a built-in controller and reads out servo information given to each sector to position the magnetic head at a predetermined position on a recording track on a magnetic disk, interleaf information is stored in advance on the magnetic disk. Write it in a predetermined location, read the interleaf information at least before receiving a seek command from the host computer, and when there is a seek command, read the ID of the sector after the seek is completed, and from that ID to the target sector. The time required is calculated based on the interleaf information, and when it is determined that the time required to reach the target sector is sufficient, the controller switches to another head and reads out the servo information corresponding to the other head.
A servo correction method characterized in that after updating a servo table regarding the other head, switching to the original head and reading information written in a target sector.