KR20090087261A - Hard disk drive and access method thereof - Google Patents

Abstract

A hard disk drive and an access method thereof are provided to keep data and recover default sector when an error occurs, by storing the same data copies in several locations on a disk. A hard disk drive(1) includes a disk(10), a head(20), and a controller(30). The head records the same data in several locations on the disk surface or reads out the same data recorded in several locations. The controller operates the head to read the recorded data in the fastest access time.

Description

Hard disk drive and access method {Hard disk drive and access method

The present invention relates to a hard disk drive and an access method thereof, and more particularly, to a hard disk drive and a method of access thereof having shortened access time.

A hard disk drive is a secondary memory device that stores and reads data while rotating a magnetic disk coated disk. Concentric circles called tracks are drawn on the disk, and data is recorded electronically in the concentric circles, and the head is used to record or read information on the track.

Hard disk drives are often used in computers because of their low cost and large storage capacity. Furthermore, hard disk drives are not only computers, but also are increasingly used in HDD recorders, mobile phones, car navigation systems, portable music players, camcoasters, and entertainment devices.

The speed of a hard disk drive is one of the important criteria that indicates the performance of a hard disk drive along with its capacity. Indicators for measuring the speed of a hard disk drive include transfer time and access time. Among them, the access time is the time required to move the position of the head of the hard disk drive to a specific track on the surface of the disk to read or write data. The faster the access time, the faster the performance of the hard disk drive and the faster the performance. It is recognized that this is excellent.

Various devices and methods have been proposed to shorten the access time. Among them, a method of increasing the rotational speed of the disk has been proposed, which may cause mechanical problems such as frequent vibration or overheating of the disk. Another method is to arrange a plurality of heads on the same surface of the disk, it is difficult to control the plurality of heads in a batch and problems such as overheating may occur.

Accordingly, an object of the present invention is to provide a hard disk drive and a method of access thereof, which have been devised to solve the above-mentioned problems of the related art.

In order to achieve the above object, the present invention proposes a hard disk drive and a method of access thereof shortened access time.

More specifically, in accordance with an aspect of the present invention, the above object is to provide a disk in which data is stored, a head for recording the same data at a plurality of locations on the surface of the disk or reading the same data recorded at the plurality of locations, and the same data. An access time of the plurality of recorded positions is achieved by a hard disk drive including a control unit for operating the head to read data recorded at the earliest position.

On the other hand, according to another aspect of the present invention, the above object is a data recording unit for storing the same data in a plurality of positions on the surface of the disk and a data read for reading the data recorded at the position of the fastest access time among the plurality of positions in which the same data is stored. It is also achieved by a hard disk drive containing a wealth.

On the other hand, according to another aspect of the present invention, the above object is to record the same data in a plurality of positions on the surface of the disc and to read the data recorded in the position with the fastest access time among the plurality of positions in which the same data is recorded. It is also achieved by a method of accessing a hard disk drive comprising the steps.

As described above, according to the present invention, a hard disk drive and a method of access thereof having shortened access time are provided.

In other words, it is possible to improve the access speed of the head by controlling the same data to be recorded at different positions on the disk surface without significantly changing the mechanical part of the hard disk drive.

Furthermore, by storing the same copy of the data in a plurality of locations on the surface of the disk, even in the case of a bad sector in which a sector fails, the copy stored in another location of the disk can be used to preserve the data or thereby recover the bad sector. It also has the effect of increasing fault tolerance (resilience).

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention; In the following description of the present invention, if it is determined that detailed descriptions of related well-known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

1 is an overview view of a hard disk drive 1 according to an embodiment of the present invention.

Referring to FIG. 1, the hard disk drive 1 includes a disk 10, a head 20, and a controller 30. Furthermore, the spindle 12 may further include an actuator 22 and an actuator motor 24.

The disk 10 stores the same data in different locations on the surface. The disk 10, also called a platter, is rotatable by a spindle 12 and data is accessed by a head 20 connected with an actuator 22 that is rotated by an actuator motor 24. do. At this time, the actuator 22 may fly the head 20 so that the data recorded on the disk 10 can be accessed.

Specifically, the hard disk drive 1 stores several identical data on one side of the disk 10. For example, the same data may be stored in two different locations on one side of the disk 10. Alternatively, the same data can be stored in three or more different locations on the disk surface. Here, the same data may be randomly stored at different locations on the disk surface, but may be stored at evenly divided locations on the disk surface. For example, the same data may be stored in a sector corresponding to a position which is divided into two parts or three parts of the disk surface.

The head 20 writes the same data at different positions on one surface of the disc 10 or reads specific data among the same data recorded at different positions. At this time, the head 20 senses a change in magnetism generated from the surface of the disk 10 and reads the information recorded on the disk 10. In addition, current is supplied to the head 20 to write data to the disk 10. The current generates a magnetic field, and the generated magnetic field magnetizes the surface of the disk 10 to record data.

Meanwhile, the controller 30 controls the head 10 to store the same data at different positions on the surface of the disk 10. Alternatively, the head 10 is controlled to read data recorded at a position where the access time is the fastest among different positions of the disc 10 on which the same data is recorded. The access time is the time taken to move the head position to the position where the specific data of the disk is stored. As access time improves, disk utilization may increase. Furthermore, even if any one of the plurality of the same data is bad, the remaining other data can be read, so that the data utilization rate can be improved since the data is preserved without being damaged. The controller 30 controls the data transmitted from the host. The host may be not only a computer but also a HDD recorder, a mobile phone, a car navigation device, a portable music player, a camcoaster, a game machine, etc., but various other electronic devices are possible.

2 is a block diagram of a control unit 30 of a hard disk drive according to an embodiment of the present invention.

Referring to FIG. 2, the control unit 30 of the hard disk drive includes a data recording unit 100 and a data reading unit 110.

The data recorder 100 stores the same data at different positions on the disk surface. The data recorder 100 may randomly store the same data on the disk surface, but may store the same data in equally divided positions on the disk surface. In this case, average access time can be reduced to one-nth, an evenly divided number. The average access time is the average time taken from the end of reading or writing specific data from the hard disk drive to the end of reading or writing the next data.

The data reading unit 110 reads the data recorded in the position where the access time is fastest among the various positions of the disk on which the same data is stored through the data recording unit 100. At this time, the data reading unit 110 reads the data stored at the position closest to the current head position among the various positions on the disk surface. Access time is the time taken to move the head position to a specific position on the disk surface.

In detail, the controller 30 selectively positions the head on a track corresponding to a position closest to the current head position among different positions where the same data on the disk is stored through a servo mechanism.

At this time, positioning the head on a specific track can be performed by two stages of servo control consisting of track seek and track following. Track search is the step of moving the head from the track in which the current head is located to the nearest track among the various positions of the disc on which the same data is stored. Track following is a step in which a head moved through track search accurately follows a track and keeps the head following the track's centerline for accurate reading or writing once the head is located on one track.

To this end, the hard disk drive 1 according to an exemplary embodiment of the present invention searches for various positions of the disk on which the same data is recorded, and calculates a distance from the found positions to the current head position. As a result of the calculation, it is controlled to position the head at the position of the nearest distance. At this time, the data reading unit 110 may control to read data of the track where the head is located.

3 is a reference diagram for describing an operation of a hard disk drive according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the data recording unit 100 of the hard disk drive records the same data at a plurality of positions on the surface of the disk 10. For example, the same data can be recorded in three different sectors of the surface track of the disk 10 as shown in FIG. In this case, the data may be distributed into multiple copies according to a write request from a host, for example, a computer, and recorded in different locations on one surface of the disk 10.

On the other hand, the data reading unit 110 reads the data recorded in the position where the access time is fastest among the various positions of the disk on which the same data is stored through the data recording unit 100. For example, as shown in FIG. 3, the head may be positioned at the position closest to the current head position to read data. In other words, among the plurality of storages recorded by the write operation, the sector of the disk which can be quickly accessed at the current head position is found and read, and then responded to a request of a host, for example, a computer.

Further, when the sector at the position with the fastest access time is bad, the data reading unit 110 may read data recorded in the sector at the position with the fastest access time from the bad sector among the various positions of the disk. Bad sectors are areas in the hard disk drive where information could not be recorded due to physical damage or magnetic defects or the storage of information became unstable, which can occur during use. In this case, when the information is stored in the bad sectors, data storage becomes unstable, which may lead to data loss.

However, since a hard disk drive according to an embodiment of the present invention includes a copy of data, even if one bad sector occurs, the hard disk drive may read or recover data through another sector in which the copy exists. That is, since there is a redundant copy, assuming that the error rate in one sector is E, the error rate of the hard disk drive according to the embodiment of the present invention can be reduced to E ⁿ .

Mean Time Between Failures (MTBF) can also be improved. Here MTBF is one of the reliability measures, which is the average of the number of hours of failure-free operation between the failure of the repairable device and the next failure, that is, from completion of the repair to the next failure. The average value can be calculated by dividing the total number of uptimes by the number of failures, and the MTBF can be extended as the bad sectors on the disk can be replaced by a surplus of other sectors.

Furthermore, fault tolerance and resilience can be increased. Fault tolerance is a computer's ability to prevent data loss or ongoing work being damaged when a power failure or hardware failure occurs that prevents normal operation. In the hard disk drive according to the exemplary embodiment of the present invention, since redundant copies of the same data are stored on the disk, the corresponding capability may be improved to increase fault tolerance.

4 is a data format diagram organized on tracks on a disc of a hard disc drive according to an embodiment of the present invention.

Referring to FIG. 4, the track corresponding to the head is alternately located between the servo sector and the data sector. The servo sector executes servo control such as track search and track following, and the data sector is provided to record data. Here, the data sector is divided into an ID field and an data field. In the ID field, header information for identifying the data sector is recorded, and data is recorded in the data field. Servo sectors are located before and after the data sectors. As shown in FIG. 4, a data sector including the same data field, for example, a first data field, may be redundantly stored in different sectors of a track.

On the other hand, data sectors are divided into logical block addresses (hereinafter referred to as LBAs) .When accessing, one sector is designated as a block unit, the first sector is serially numbered 0, and then the physical address is addressed. It is specified with the three-dimensional address of the cylinder, head, and sector. The number of cylinders, heads, and sectors represented by the LBA are all different from the actual physical numbers, and the data addresses are reconstructed in a logical way.

5 is a reference diagram illustrating an access time of a hard disk drive according to an exemplary embodiment of the present invention.

Referring to FIG. 5, as shown in FIG. 5, the data is stored in different positions 100a and 100b of the disk, thereby reducing the time for which the data reaches the head. That is, when the rotation angle of the disk is divided by the angular velocity, which is the angular displacement per unit time, as the access time, the approach time of the sector 100a far from the position of the current head 20 is located close to the position of the current head 20. Is slower than sector 100b. Therefore, when the data is read, the head 20 is located in a sector 100b located close to each other, thereby reducing the access time, thereby increasing the working speed of the hard disk drive and improving performance.

6A and 6B are reference diagrams for describing a data recording method of a hard disk drive according to various embodiments of the present disclosure.

6A and 6B, sectors in which the same data is recorded may be present in the divided portions 200a and 200b of the disc as shown in FIG. 6A. Or in three divided positions 300a, 300b, 300c of the disk. By recording data in n equal parts of the disk, redundant copies can be stored on the disk surface. However, this method is only one embodiment and various other embodiments may be implemented.

7 is a flowchart illustrating a method of accessing a hard disk drive according to an embodiment of the present invention.

Referring to FIG. 7, the hard disk drive writes the same data to a plurality of locations on the disk surface (S100). In this case, data may be recorded at different positions on the surface of the disc, for example, n equal portions of the disc.

Then, the data recorded in the position where the access time is the fastest among the plurality of positions where the same data is recorded is read. First, the head is positioned at the position where the access time is the fastest among the plurality of positions where the same data is recorded (S110). At this time, the head may be positioned at the position closest to the distance based on the distance calculation with the current head position by searching for different positions of the disc on which the same data is recorded. Further, when the sector at the position with the fastest access time is bad, data recorded in the sector at the position with the fastest access time can be read from the bad sector among the plurality of positions. Subsequently, data recorded in the sector in which the head is located is read (S120).

In summary, the hard disk drive and its access method according to an embodiment of the present invention controls the access speed of the head by controlling the same data to be written at different locations on the surface of the disk without significantly changing the mechanical part of the hard disk drive. Can improve. Furthermore, by storing copies of the same data in different locations on the surface of the disc, even in the case of bad sectors in which sectors fail, the copies stored in different locations on the disc can be used to recover or preserve bad sectors.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown not in the above description but in the claims, and all differences within the scope will be construed as being included in the present invention.

1 is an overview of a hard disk drive according to an embodiment of the present invention;

2 is a block diagram of a control unit of a hard disk drive according to an embodiment of the present invention;

3 is a reference diagram for explaining an operation of a hard disk drive according to an embodiment of the present invention;

4 is a data format diagram organized on tracks on a disc of a hard disc drive according to an embodiment of the present invention;

5 is a reference diagram for explaining an access time of a hard disk drive according to an embodiment of the present invention;

6A and 6B are reference diagrams for describing a data recording method of a hard disk drive according to various embodiments of the present disclosure;

7 is a flowchart illustrating a method of accessing a hard disk drive according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1: hard disk drive 10: disk

12: spindle 20: head

22: actuator 24: actuator motor

30 control unit 100 data recording unit

110: data reading unit

Claims (8)

A disk on which data is stored; A head for recording the same data at a plurality of positions on the surface of the disc or reading the same data recorded at the plurality of positions; And And a control unit for operating the head to read data recorded at a position where the access time is the fastest among the plurality of positions at which the same data is recorded. A data recording section for storing the same data in a plurality of positions on the surface of the disc; And And a data reading unit which reads data recorded at a position where the access time is the fastest among the plurality of positions in which the same data is stored. The method of claim 2, And the data recording section stores the same data at equally divided positions on the surface of the disk. The method of claim 2, And the data reading unit reads data stored at a position closest to a current head position among a plurality of positions on the surface of the disc. (a) recording the same data at a plurality of locations on the surface of the disc; And and (b) reading the data recorded at a position where the access time is the fastest among the plurality of positions at which the same data is recorded. The method of claim 5, wherein The step (b) is a method for accessing a hard disk drive, when the sector of the position having the earliest access time is defective, reading the data recorded at the position with the fastest access time from the bad sector among the plurality of positions. The method of claim 5, wherein step (b) (b1) positioning the head at a position where the access time is fastest among the plurality of positions at which the same data is recorded; And (b2) accessing a hard disk drive, comprising reading data recorded in a sector in which the head is located. The method of claim 7, wherein The step (b1) is a method for accessing a hard disk drive in which the head is located at the closest position based on a distance calculation with a current head position by searching the plurality of positions where the same data is recorded.

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