KR100312103B1 - Method and apparatus for rewriting servo information on disk in hard disk drive assembly - Google Patents

Abstract

The present invention provides a method and apparatus for rewriting servo information on a disk of a hard disk drive. The scene servo pattern is recorded on a track on the head or side of the disc pack using the staggered wedge method. When the read / write head reaches a first track located beyond the inner circumference crash stop of the disc pack, the first read / write head starts recording to record data in each sector of the entire track after writing the new servo information. While the other read / write heads remain disabled. The data is overwritten on any existing servo information on the track. Then, the second read / write head is started to record the new servo information and then write data to each sector of the complete track, while the other read / write heads remain inactive. During a power-on sequence operation, the read / write heads are directed to a portion of the disk beyond the inner crash stop where the new servo pattern and new data are written to read the new servo pattern.

Description

Method and apparatus for rewriting servo information on disk in hard disk drive assembly

The present invention relates to a disk storage system, and more particularly to a method and apparatus for rewriting servo information on a disk in a hard disk drive assembly.

Disk drives are magnetic recording devices used for storing information. Such information is typically recorded on concentric tracks formed on one or more magnetic recording disks. To facilitate the storage and retrieval of data, discs are organized into blocks called sectors. These sectors are placed on the disc by a series of specific elements called cylinders (or tracks), heads (or sides) and sector numbers. The disks are rotatably mounted to the spindle motor and the information is accessed by read / write heads mounted to the actuator arm that is rotated by the voice coil motor. The voice coil motor is excited by a current to rotate the actuator to move the head.

The movement of the actuator is controlled by the servo system using servo information recorded on one or more magnetic recording disks. By reading this servo information, the actual radial position of the heads is determined, compared with the radial position of the desired head, and then a control signal is sent to move the actuator. Servo information is typically stored on disk in one of two ways. In the first method, the dedicated servo system, the entire disk surface or a plurality of tracks of the disk are set to store only information related to a specific drive characteristic. The information includes servo parameters and read / write parameters. The servo head reads this information and provides a continuous signal indicating the position of the servo head relative to the servo disk. In the case of an embedded servo system in the second method, the sectors of the servo information are intermingled with the sectors of data on the respective disk surface. The read head follows the data tracks so that the read head regularly reads new samples of servo information from each servo sector in order to control its position.

Due to the power consumption, cost and throughput relationship, the "stagger wedge" servo method is well known in the disc drive industry as a special form of the embedded servo method. In the staggered wedge servo system, the servo information recorded on the side of each head or disk is not aligned. Instead, the servo information is staggered. As shown in Fig. 1, the servo information stored on the track of one disk head is phase-shifted from the servo information stored on the same track of another disk head.

For example, in writing a servo pattern on a staggered wedge hard disk drive having four heads (R / W heads 1 to R / W head 4), read / write (hereinafter referred to as "R / W"). Head 1 is activated for the first time to write a specific servo pattern to sector 1, head (or side 0) H0, track 1 of the disk pack of the hard disk drive assembly. When the servo writing process is completed, the R / W head 1 is stopped. Then, the R / W head 2 is activated to record the servo pattern in sector 1, head (or side) H1, track 1 of the disc pack. When the servo writing process is completed, the R / W head 2 is stopped. The same process is applied to the sector 1, head (or side) H2, track 1 and sector 1, head (or side) H3, and track 1 of the disc pack, respectively, for the R / W head 3 and the R / W head 4. Continues. Therefore, the servo pattern is written to all four disk heads of the disk pack during a particular sector cycle.

By operating one R / W head at a time, the staggered wedge servo recording method can efficiently complete servo recording of the entire cylinder with minimal power consumption. However, such a servo recording method causes a serious problem when used for the purpose of rewriting servo information on a disk pack of a hard disk drive assembly. In particular, since only one R / W head (e.g., R / W head HO) is activated at a particular time, the remaining heads (e.g., R / W heads H1-3) are in a down state. As a result, the data fields of the heads H1 to 3, sector 1 of the disk pack will not have any data recorded. When a new servo pattern is written on the disk pack, two servo patterns, that is, an old servo pattern and a new servo pattern, will coexist on the disk pack as shown in Fig. 2, and as a result, to read the reworked disk. It will cause confusion while trying.

One way to solve this problem is to erase the previous servo information on the entire disk pack before rewriting the servo pattern on the disk pack. However, this method significantly reduces the throughput, and thus results in a significant decrease in the manufacturing productivity of the hard disk drive.

Accordingly, it is an object of the present invention to provide a method and apparatus for rewriting servo information on a disk pack of a hard disk drive assembly without preferentially erasing previous servo information on the entire disk pack.

In order to achieve the above object, the present invention provides a method for rewriting servo information on a disc of a hard disk drive, comprising the steps of: (a) providing a disc defined by a plurality of tracks each having existing servo information; ; (b) recording servo information and data on at least one track of the disc.

The present invention provides a method and apparatus for rewriting servo information on a disk of a hard disk drive. The new servo pattern is recorded in the track on the head or side of the disc pack using the staggered wedge method. When the read / write head reaches the first track located beyond the inner circumference crash stop of the disc pack, the first read / write head starts to record the new servo information and then write data to each sector of the entire track, while The other read / write heads will remain inactive. The data is overwritten on any existing servo information on the track. Then, the second read / write head is started to record the new servo information and then write data to each sector of the complete track, while the other read / write heads remain inactive. During a power-on sequence operation, the read / write heads are directed to a portion of the disk beyond the inner crash stop where the new servo pattern and new data are written to read the new servo pattern.

1 illustrates a servo pattern on a disk pack of a hard disk drive assembly recorded using a stagger wedge servo writing system according to the prior art.

FIG. 2 illustrates a state in which old and new servo patterns coexist on a disc pack using a staggered wedge servo recording method according to the prior art. FIG.

3A illustrates a servo recording system for implementing a method according to an embodiment of the present invention.

FIG. 3B is a perspective view of some components of the servo recording system of FIG. 3A; FIG.

4 illustrates a hard disk drive using one aspect of a method according to an embodiment of the invention.

5A shows sector 1, head 0 of the disk pack.

Fig. 5B shows a data sector of a disc of a disc pack having four heads and servo information recorded using a staggered wedge servo recording method.

FIG. 6 is a plan view of a re-servo written disk pack according to one embodiment of the present invention. FIG.

7A and 7B are flowcharts illustrating a rewriting process of servo information according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same parts throughout the drawings. In addition, detailed descriptions of well-known functions and components that may obscure the gist of the present invention will be omitted herein.

FIG. 3A is a schematic diagram showing the configuration of a servo recording system 10 for performing a re-servo writing process of the present invention. Referring to FIG. 3A, the servo recording system 10 enters the re-servo recording process by positioning the R / W head in the magnetic disk drive from the master arm and the motor. The servo recording system 10 includes a mast drive assembly 12 comprising a master arm 14 having a master voice coil motor (hereinafter referred to as "master arm motor") 16. It also includes a hard drive assembly 18 that includes a hard drive arm 20 having a hard drive voice coil motor (hereinafter referred to as a "hard drive arm motor").

In order to ensure accurate positioning of the master arm 14, a laser interferometer 24 is used to measure the position of the master arm 14. This information is conveyed to the master arm servo controller 26 which moves the master arm 14 to the desired track of the data storage disk to be recorded. The laser interferometer 24 detects the position of the master arm 14 by monitoring the light reflected by the reflector 28 mounted on the master arm 14. This information is passed to the master arm servo controller 26. The mast arm servo controller 26 also receives a position command signal provided from an external source such as a computer programmed to adjust the servo write operation.

The mechanical connection between the master arm 14 and the hard drive arm 20 is established using a mechanical push-pin 30 as shown in FIGS. 3A and 3B. One end of the push-pin 30 is mounted to the master arm 14 and extends to the hard drive through an access slot. Hard drive arm 20 is biased by hard drive arm motor 22 to press and follow the master arm 14 through the side of the push-pin 30. This mechanical positioning system enables the hard drive arm 20 to track the movement of the master arm 14, thus ensuring the recording of servo information at the appropriate radius of the hard drive assembly 18.

4 shows the hard disk drive assembly 18 of FIG. 3A. Referring to FIG. 4, the hard disk drive assembly 18 includes a disk pack 100 having a plurality of disks 102 that are collectively rotated by a spin motor 104. The spin motor 104 corresponds to the hard drive arm motor 22 of FIG. 3A. The spin motor 104 is mounted to the base plate 106. An actuator arm assembly 108 is also mounted to the base plate 106. The actuator arm assembly 108 corresponds to the hard drive arm 20 of FIG. 3A. The actuator arm assembly 108 includes a plurality of R / W heads 110a-d mounted to a corresponding flexure arm 112. The flexure arm 112 is attached to an actuator arm 114 that rotates around the bearing assembly 116. The actuator arm assembly 108 also includes a voice coil motor 118 that collectively moves the heads 110a-d relative to the disk 102. A single R / W head 110a, 110b, 110c or 110d is correspondingly present for the disc head side H0, H1, H2 or H3 (not shown) of the disc pack 100, respectively. The spin motor 104, voice coil motor 118 and R / W heads 110a-d are connected to a number of electronic circuits 120 mounted on a printed circuit board 122. The electronic circuit 120 typically includes a read channel chip, a microprocessor-based controller, and a random access memory (RAM) device.

As shown in FIG. 5A, data is stored in sectors of a radial concentric track located across one of the disk heads H 0 -H 3 of the disc pack 100. A typical sector is a preamble field 150 containing Automatic Gain Control (AGC) information and synchronization information, an address mark 152 indicating the beginning of the sector, and an index field indicating the beginning of the first sector of the track. 154, with gray code field 156 identifying the particular cylinders (tracks) of the sector, servo field 158 with multiple servo bits A, B, C and D and data field 160 containing data have. Electronic circuit 120 uses the servo bits A, B, C and D to hold the heads 110a-d on the centerline CL of the corresponding track. The heads 110a-d magnetize and sense the magnetic field of the disk heads H0-H3.

FIG. 5B shows a sector of the disc 102 of the disc pack 100 having the servo information recorded using the staggered wedge servo recording method and four disc heads H0, H1, H2 and H3. 5B, each of the disk heads H0, H1, H2 and H3 has a servo field 148 and a data field 160 as described above. In recording the servo pattern on the four head disk pack 100 planes, each of the R / W heads 110a, 110b, 110c or 110d is operated individually, so that the head (or side) of the disk pack 100 H0, H1, H2. Or go to a specific sector such as H3 and sector 1 and record a specific servo pattern. When the servo write operation is completed, the operation of the specific R / W head 110a, 110b, 110c or 110d is stopped. As a result, the servo patterns for all four heads H0-H3 of the disk pack 100 are recorded during a particular sector cycle.

6 is a plan view showing a re-servo written disc pack according to a preferred embodiment of the present invention. Referring to FIG. 6, in recording a servo pattern of a rework disk, in the re-servo recording process according to an embodiment of the present invention, the master is to first mechanically position the disk drive arm 20 on the outermost track. Directed to Cancer 14. Then, the R / W heads 110a-d are instructed to record the servo pattern according to the staggered wedge method as described above. In particular, the R / W head 110a is first operated to instruct the R / W head 110a to write a specific servo pattern in the head (or side) H0 and sector 1 of the disc pack 100. When the servo recording process is completed, the R / W head 110a is stopped. Then, the R / W head 110b is operated to instruct the R / W head 110b to write a specific servo pattern in the head H1, sector 1 of the disc pack 100. When the servo writing process is completed, the R / W head 110b is stopped. The same process as described above continues for the head pack H2, sector 1 and the head H3, sector 1 of the disc pack 100 even in the case of the R / W head 110c and the R / W head 110d.

Upon reaching the first track, such as track 200, just beyond the inner crash stop, a re-servo recording process in accordance with an embodiment of the present invention, in one of the heads 110a-d, Instructs to record the servo pattern and data for one complete track regardless. By recording the data on the track after the new servo pattern is recorded, redundancy on any existing servo pattern is guaranteed. This re-servo recording process is achieved, for example, by first instructing the R / W head 110a to record the servo pattern and data for one complete track. Once this is done, it instructs the second R / W head 110b to record the servo pattern and data for the corresponding complete track. Next, the third R / W head 110c is instructed to record the servo pattern and data for the corresponding complete track. Finally, the fourth R / W head 110d is instructed to record the servo pattern and data for the corresponding complete track. This process is performed from the first track to the fiftyth track located beyond the inner crash stop.

During the power-up sequence, actuator arm assembly 108 is biased beyond the inner circumferential crash stop where only a new servo pattern is present. The R / W heads 110a-d are then positioned at the beginning of the new servo pattern and instructed to synchronize the reading of the new servo pattern. Once this is done, the calibration process begins.

7A illustrates a flowchart for describing a process of rewriting servo information according to an exemplary embodiment of the present invention. Referring to FIG. 7A, starting from the start state, the process S200 of the present invention proceeds to step S202 of the process to position the disc drive arm 20 as the outermost track of the disc 102 of the disc pack. (FIG. 3A). The process S200 then starts recording of the servo pattern for each head H0-H3 of the disc pack 100 using a staggered wedge method, as shown in step S204 of the process. tell -d. In particular, the current drive R / W head 110a is first activated, and the servo controller 132 (FIG. 5) instructs the R / W head 110a to write the new servo pattern to the head H0 of the disc pack 100. When this operation is completed, the R / W head 110a is stopped while the R / W head 110b is operated. The servo controller 132 then instructs the R / W head 110b to write a new servo pattern on the head H1 of the disk pack 100. When this operation is completed, the R / W head 110b is stopped while the R / W head 110c is operated. At this time, the servo controller 132 instructs the R / W head 110c to write the new servo pattern to the head H2 of the disk pack 100. When the recording operation of the scene servo pattern by the R / W head 110c is completed, the R / W head 110c is stopped, while the R / W head 110d is activated and the head H3 of the disk pack 100 is operated. The R / W head 110d is instructed to record the servo pattern.

In decision step S206 of step S200, it is determined whether the disk drive arm 108 has reached the inner circumferential crash stop of the hard disk drive assembly 18. If the inner crash stop has not been reached, the process S200 proceeds to step S208 to continuously perform the operation of writing a new servo pattern to each head H0-H3 of the disk pack 100 using a staggered wedge method. The heads 110a-d are instructed. The position of the disk drive arm 108 is continuously monitored to determine whether the disk drive arm 108 has reached the inner circumferential crash stop.

If it is determined in step S206 that the disk drive arm 108 has reached the inner crash stop, process S200 proceeds to step S210 to record the new servo pattern and new data on all sectors of one complete track. To each R / W head 110a-d. This is accomplished by operating each R / W head 110a, 110b, 110c or 110d for one complete track at a time. For example, the R / W head 110a is turned on while the R / W head 110b-d is turned off. The R / W head 110a is instructed to write the new servo pattern and new data on all sectors of one complete track 200. By performing this operation, old servo patterns will be overwritten by the new servo pattern and new data. Once this is done, the R / W head 110a will be turned off, but the R / W head 110b will be turned on. The R / W head 110b is instructed to write the new pattern and new data on all sectors of the same complete track 200 located on head H1. This step S214 is continuously performed for a preset number of tracks, for example 50 tracks.

Subsequently, the process S200 proceeds to the determination step S212 to determine whether the new servo pattern and the new data have been recorded on a predetermined number of tracks over each head H0-H3. If it is determined in step S212 that the new servo pattern and new data are not recorded on the preset number of tracks, the process S200 proceeds to step S214 where one head H0, H1, H2 is at a time. Or instructs the R / W heads 110a-d to continue the operation of recording the new servo pattern and new data for H3. Then, the process proceeds to the determination step S214 in step S212 to determine whether the new servo pattern and the new data have been recorded on the predetermined number of tracks.

If it is determined in step S212 that the new servo pattern and new data are recorded on the predetermined number of tracks, the process S200 ends.

7B is a flowchart for describing a process S250 of reading the scene servo pattern according to an exemplary embodiment of the present invention. When the re-servo recording process S200 is completed, the reading process of the new servo pattern may be started. This process S250 is performed under the control of the servo controller 132 of the disk drive assembly when the disk drive assembly is removed from the servo writer.

Starting from the start state, the process 250 may be arranged in step S252, for example, to position the disk drive arm 108 into an area of the disk pack 100 where the new servo pattern and new data are recorded on the track 200 (FIG. 6). Instruct on. The process S250 then proceeds to step S254 to instruct the heads 110a-d to be positioned at the beginning of the new servo pattern. Subsequently, the process S250 proceeds to step S256 to instruct the heads 110a-d to perform a calibration process on the disk pack 100 based on the new servo pattern. The process S250 then proceeds to decision step S258 to determine whether the calibration process has been completed. If it is determined in step S258 that the calibration process is not completed, the process S250 proceeds to step S260 to continue the calibration process. Then, the process S250 returns to the determination step S258. If the calibration process is completed in the determination step S258, the process S250 is terminated.

It will be appreciated that the present invention can be used to rewrite servo information on a disc using any other servo write technique. For example, the present invention can also be used to rewrite servo information using an aligned servo writing scheme instead of a staggered wedge approach. The present invention may also be used to record servo information on a first plurality of tracks and then record servo information and data on a second plurality of tracks that are complete tracks. In this way, new servo information can be recorded on the disc without extending beyond the inner circumference crash stop of the disc pack.

While the invention has been described with reference to specific embodiments so far, the disclosure of the invention is merely an application of the invention and is limited to the specific embodiments disclosed herein as the best mode for carrying out the invention. It is not. In addition, while the invention has been shown and described with reference to certain preferred embodiments, it will be understood that the invention can be variously modified and modified without departing from the spirit or scope of the invention as set forth in the claims below. It will be apparent to those skilled in the art.

According to the present invention as described above, by implementing the technique of the present invention, it is possible to rewrite the servo information on the disk head of the disk pack without first erasing the previous information of the entire disk pack, and as a result, the hard disk drive While the manufacturing productivity of the disk pack can be greatly improved, the cost of reworking such a disk pack is reduced.

Claims (8)

A method for rewriting servo information on a disk of a hard disk drive, comprising: (a) providing a disk defined by a plurality of tracks each having existing servo information; (b) recording servo information and data on at least one track of the disc. The method of claim 1, (c) reading the servo information from at least one track of the disc; and (d) providing calibration information for the disk based on the servo information. The method of claim 1, wherein in step (b), at least one track is disposed beyond an inner circumferential crash stop position of the disc. 2. The method of claim 1, wherein in the step (a), the plurality of tracks comprises a first plurality of tracks and a second plurality of tracks, and in step (b), at least one track is the first plurality of tracks. Located within the track, The method further comprising recording servo information in the second plurality of tracks prior to performing step (b). For disks for hard disk drives: A disk having a first plurality of tracks and a second plurality of tracks disposed beyond an inner circumferential crash stop position of the disk, the disk having a first servo field formed on each track of the first plurality of tracks. And a second servo burst of the second servo field and a first burst of the first servo field and a data burst of the data field formed on each track of the second plurality of tracks. Disk for the disk drive. 6. The hard disk of claim 5, wherein the first servo burst of the first plurality of tracks and the second plurality of tracks is a newly recorded servo burst, and the second servo burst is a previously recorded servo burst. Disk for drive. For hard disk drives: A housing; A spin motor mounted to the housing; An actuator arm mounted to the spin motor; A disk attached to the spin motor; A read / write head mounted to the actuator arm for reading at least one side of the disc, The disk has a first plurality of tracks and a second plurality of tracks disposed beyond an inner crash stop position of the disk, the disk having a first servo of a first servo field formed on each track of the first plurality of tracks. A hard disk having a burst and a second servo burst of a second servo field, and having a first servo burst of a first servo field and a data burst of a data field formed on each track of the second plurality of tracks. drive. 8. The hard disk drive of claim 7, wherein the first servo burst of the first multitrack and the second multitrack is a newly recorded servo burst and the second servo burst is a previously recorded servo burst.