CN-121999809-A - Data storage device with auxiliary bursts in servo sectors

Abstract

The present disclosure relates to data storage devices having auxiliary bursts in servo sectors. Various illustrative aspects relate to a data storage device, a method, and one or more processing devices configured to open a servo gate in a selected head during a read operation to read a first servo burst, a sync mark, and a second servo burst in one of the servo sectors, and to determine a position error signal for the selected head based on reading the first servo burst and the second servo burst.

Inventors

• GUO GUOXIAO
• C. A. PARK
• HONG YUN
• Otell, S.A.
• HERBST GERHARD
• Shan Bencong

Assignees

• 西部数据技术公司

Dates

Publication Date

20260508

Application Date

20250616

Priority Date

20241105

Claims (20)

1. 1. A data storage device, the data storage device comprising: One or more discs each comprising a plurality of servo sectors defining a plurality of data tracks, wherein each of the servo sectors comprises a first servo burst followed by a sync mark followed by a second servo burst; an actuator mechanism configured to position a selected head of the one or more heads adjacent a corresponding disk surface of a corresponding disk of the one or more disks, and One or more processing devices configured, alone or in combination, to: Opening a servo gate in said selected head during a read operation to read said first servo burst, said sync mark, and said second servo burst in one of said servo sectors, and A position error signal for the selected head is determined based on reading the first servo burst and the second servo burst.
2. 2. The data storage device of claim 1, wherein the read operation is configured to read data stored in a data sector immediately following the one of the servo sectors.
3. 3. The data storage device of claim 1, wherein each of the servo sectors further comprises a track ID between the first servo burst and the second servo burst.
4. 4. The data storage device of claim 1, wherein each of the servo sectors lacks a preamble.
5. 5. The data storage device of claim 1, wherein each of the servo sectors further comprises a preamble between the first servo burst and the second servo burst.
6. 6. The data storage device of claim 1, wherein the position error signal comprises an average of a first position error signal determined using the first servo burst and a second position error signal determined using the second servo burst.
7. 7. The data storage device of claim 6, wherein the average is a weighted average based on a first number of burst cycles associated with reading the first servo burst and a second number of burst cycles associated with reading the second servo burst.
8. 8. The data storage device of claim 1, wherein: The first servo burst includes a first burst and a second burst; The second servo burst includes a third burst and a fourth burst; the first pulse train and the third pulse train are of a first pulse train type, and The second burst and the fourth burst are of a second burst type different from the first burst type.
9. 9. The data storage device of claim 8, wherein the position error signal is determined using a sum of values obtained by reading the first pulse train and the third pulse train and a sum of values obtained by reading the second pulse train and the fourth pulse train.
10. 10. The data storage device of claim 8, wherein determining the position error signal comprises: Performing a first asynchronous position error signal calculation using the first burst and the second burst; performing a second asynchronous position error signal calculation using the third burst and the fourth burst, and The position error signal is determined based on the first asynchronous position error signal calculation and the second asynchronous position error signal calculation.
11. 11. The data storage device of claim 1, wherein each of the servo sectors further comprises Repeatable Runout (RRO) correction data.
12. 12. The data storage device of claim 11, wherein the RRO correction data is followed by the synchronization mark.
13. 13. The data storage device of claim 1, wherein the one or more processing devices, alone or in combination, are further configured to control the position of the selected head using the position error signal.
14. 14. The data storage device of claim 1, wherein: the first servo burst comprising a first split burst servo pattern, and The second servo burst includes a second split burst servo pattern.
15. 15. A method, the method comprising: During a read operation, a servo gate in a selected head is opened to read a first servo burst followed by a second servo burst in a servo sector lacking a preamble; determining a position error signal for the selected head based on reading the first servo burst and the second servo burst, and The position error signal is used to control the position of the selected head, Wherein opening the servo gate, determining the position error signal, and controlling the position of the selected head are performed by one or more processing devices, alone or in combination.
16. 16. The method according to claim 15, wherein: The first servo burst includes a first burst and a second burst; The second servo burst includes a third burst and a fourth burst; the first pulse train and the third pulse train are of a first pulse train type, and The second burst and the fourth burst are of a second burst type different from the first burst type.
17. 17. One or more processing devices, the one or more processing devices comprising: Means for opening a servo gate in a selected head during a read operation to read Repeatable Runout (RRO) correction data in a servo sector, followed by a sync mark, followed by a servo burst; Means for generating a control signal for the selected head based on reading the RRO correction data and the servo bursts, and Means for controlling the position of the selected head using the control signal.
18. 18. The one or more processing devices of claim 17, wherein: the servo sector includes a first servo burst preceding the sync mark; the servo bursts after the sync mark include a second servo burst, and The control signal is generated based on reading the RRO correction data, the first servo burst, and the second servo burst.
19. 19. The one or more processing devices of claim 18, further comprising means for determining a position error signal using respective values obtained by reading the first and second servo bursts.
20. 20. The one or more processing devices of claim 17, wherein the servo sector comprises a preamble located between the RRO correction data and the synchronization mark.

Description

Data storage device with auxiliary bursts in servo sectors Background A data storage device, such as a disk drive, includes a disk and a magnetic head connected to a distal end of an actuator arm that is pivoted by a Voice Coil Motor (VCM) to position the magnetic head radially over the disk. The disk includes a plurality of radially-spaced concentric tracks for recording user data sectors and servo wedges or servo sectors. The servo sectors include head positioning information (e.g., track addresses) that is read by the head and processed by a servo control system to control the actuator arm as it seeks from track to track. FIG. 1 illustrates a prior art disk format 2 as including a plurality of radially-spaced concentric servo tracks 4 defined by servo wedges 6 0-6N recorded around the circumference of each servo track. A plurality of concentric data tracks are defined with respect to the servo track 4, wherein the data tracks may have the same or different radial density (e.g., track Per Inch (TPI)) as the servo track 4. Each servo wedge 6 i includes a preamble 8 for storing a periodic pattern (which allows proper gain adjustment and timing synchronization of the read signal) and a sync mark 10 for storing a special pattern for symbol synchronization to a servo data field 12. The servo data field 12 stores coarse head positioning information, such as servo track addresses, for positioning the head over the target data track during seek operations. Each servo wedge (e.g., servo wedge 6 4) also includes a plurality of sets of phase-based servo bursts 14 (e.g., N-servo bursts and Q-servo bursts) recorded at predetermined phases relative to each other and relative to the servo track centerline. The coarse head position information is processed to position the head over the target data track during seek operations, and the servo bursts 14 provide fine head position information for centerline tracking when accessing the data track during write/read operations. A Position Error Signal (PES) is generated by reading the servo bursts 14, where PES represents the measured position of the head relative to the centerline of the target servo track. The servo controller processes the PES to generate control signals that are applied to one or more head actuators to actuate the heads radially over the disk in a direction that reduces the PES. In some examples, the one or more head actuators may include a voice coil motor, and one or more fine control actuators (such as milli-actuators or micro-actuators). Disclosure of Invention Various examples disclosed herein provide a data storage device (such as a hard disk drive) having control circuitry configured to perform a novel and inventive position error signal determination using values obtained by reading respective first and second servo bursts in servo sectors lacking a preamble. In various examples, the servo sector includes a first servo burst followed by a sync mark followed by a second servo burst in a longitudinal direction of a track containing the servo sector. In some embodiments, since the servo sector does not include a preamble, the first servo burst may be written at the beginning of the servo sector where the preamble would normally be written. In an embodiment, the first servo burst written in the region of a servo sector provides an additional servo burst for the servo sector as compared to the servo sector including the preamble at the region. In an embodiment, the additional servo bursts increase the amount of servo burst information that can be used to determine the PES, which advantageously reduces the Repeatable Runout (RRO) component of the PES associated with the read operation. Various illustrative aspects relate to a data storage device that includes one or more disks that each include a plurality of servo sectors defining a plurality of data tracks, wherein each of the servo sectors includes a first servo burst followed by a sync mark followed by a second servo burst, an actuator mechanism configured to position a selected one of the one or more heads adjacent a corresponding disk surface of a corresponding one of the one or more disks, and one or more processing devices. The one or more processing devices, individually or in combination, are configured to open a servo gate in the selected head to read the first servo burst, the sync mark, and the second servo burst in one of the servo sectors during a read operation, and to determine a position error signal for the selected head based on reading the first servo burst and the second servo burst. Various illustrative aspects relate to a method that includes, during a read operation, opening a servo gate in a selected head to read a first servo burst followed by a second servo burst in a servo sector lacking a preamble, determining a position error signal for the selected head based on reading the first servo burst and the second servo burst, and controlling a position of the selected head using t