Hard disk drive (HDD), method improving read hit ration in HDD, and medium recording computer program performing method

1. A method for increasing read hits to pre-fetch data stored in a memory associated with a hard disk drive (HDD), the method comprising:

receiving a read command indicating a target sector on a disk in the HDD;

obtaining a latency time (T L ) in relation to a movement time (T M ) and a search time (T S );

wherein the movement time (T M ) is defined as the time required to rotate the disk, such that the target sector moves from an initial position (P 0 ) to a target position (P 1 ), and the search time (T S ) is defined as the time required to move a magnetic head in the HDD from a current position (P C ) to the target position (P 1 ); and

during the latency time (T L ), reading pre-fetch data from the disk at the current position (P C ) and storing the pre-fetch data in the memory before executing the received read command,

wherein when T M is less than T S , obtaining the latency time (T L ) comprises subtracting the movement time (T M ) from the search time (T S ) to obtain a subtractive result, and then subtracting the subtractive result from a rotational period time (TD), the rotational period time (TD) being defined as the amount of time required for the disk to complete one full revolution.

2. The method of claim 1 , wherein when T M is greater than or equal to T S , obtaining of the latency time (T L ) comprises obtaining the movement time (T M ) and the search time (T S ), and subtracting the search time (T S ) from the movement time (T M ).

3. The method of claim 2 , wherein, the movement time (T M ) is obtained from an equation,

T

M

=

N

H

-

N

TS

N

S

⁢

T

D

,

wherein N TS is physical information data regarding the target sector, N H is physical information data regarding a sector associated with the current position (P C ) of the magnetic head, N S is the number of the sectors included in a target track associated with the target sector, and TD is a rotational period time required to complete one revolution of the disk.

4. The method of claim 2 , wherein the search time (T S ) is obtained using a search time table in relation to a number of tracks the magnetic head must move from the current position (P C ) to the target position (P 1 ).

5. A method of increasing read hits to pre-fetch data stored in a memory associated with a hard disk drive (HDD), the method comprising:

receiving a read command indicating a target sector on a disk in the HDD;

obtaining latency time (T L ) in relation to a movement time (T M ) and a search time (T S );

wherein the movement time (T M ) is defined as the time required to rotate the disk, such that the tar et sector moves from an initial position (P 0 ) to a target position (P 1 ), and the search time (T S ) is defined as the time required to move a magnetic head in the HDD from a current position (P C ) to the target position (P 1 ); and

during the latency time (T L ), reading pre-fetch data from the disk at the current position (P C ) and storing the pre-fetch data in the memory before executing the received read command,

wherein reading pre-fetch data during the latency period (TL) comprises:

comparing the latency time (TL) with a reference time (TR); and

reading pre-fetch data from the disk at the current position (P 0 ) for a period of time equal to latency time (TL) minus the reference time (TR), if (TL) is greater than (TR), else immediately moving the magnetic head to the target position (P 1 ).

6. A non-transitory computer readable recording medium for recording a computer program performing a method for increasing read hits to pre-fetch data stored in a memory associated with a hard disk drive (HDD), the method comprising:

receiving a read command indicating a target sector on a disk in the HDD;

obtaining a latency time (T L ) in relation to a movement time (T M ) and a search time (T S );

wherein the movement time (T M ) is defined as the time required to rotate the disk, such that the target sector moves from an initial position (P 0 ) to a target position (P 1 ), and the search time (T S ) is defined as the time required to move a magnetic head in the HDD from a current position (P C ) to the target position (P 1 ); and

during the latency time (T L ), reading pre-fetch data from the disk at the current position (P C ) and storing the pre-fetch data in the memory before executing the received read command,

wherein when T M is less than T S , obtaining the latency time (T L ) comprises subtracting the movement time (T M ) from the search time (T S ) to obtain a subtractive result, and then subtracting the subtractive result from a rotational period time (TD), the rotational period time (TD) being defined as the amount of time required for the disk to complete one full revolution.

7. The method of claim 6 , wherein when T M is greater than or equal to T S , obtaining of the latency time (T L ) comprises obtaining the movement time (T M ) and the search time (T S ), and subtracting the search time (T S ) from the movement time (T M ).

8. The method of claim 7 , wherein, the movement time (T M ) is obtained from an equation,

T

M

=

N

H

-

N

TS

N

S

⁢

T

D

,

wherein N TS is physical information data regarding the target sector, N H is physical information data regarding a sector associated with the current position (P C ) of the magnetic head, N S is the number of the sectors included in a target track associated with the target sector, and TD is a rotational period time required to complete one revolution of the disk.

9. The method of claim 7 , wherein the search time (T S ) is obtained using a search time table in relation to a number of tracks the magnetic head must move from the current position (P C ) to the target position (P 1 ).

10. A method of increasing read hits to pre-fetch data stored in a memory associated with a hard disk drive (HDD), the method comprising:

receiving a read command indicating a target sector on a disk in the HDD;

obtaining a latency time (T L ) in relation to a movement time (T M ) and a search time (T S );

wherein the movement time (T M ) is defined as the time required to rotate the disk such that the tar et sector moves from an initial position (P 0 ) to a target position (P 1 ), and the search time (T S ) is defined as the time required to move a magnetic head in the HDD from a current position (P C ) to the target position (P 1 ); and

during the latency time (T L ), reading pre-fetch re-fetch data from the disk at the current position (P C ) and storing the pre-fetch data in the memory before executing the received read command,

wherein reading pre-fetch data during the latency period (T L ) comprises:

comparing the latency time (T L ) with a reference time (TR); and

reading pre-fetch data from the disk at the current position (P C ) for a period of time equal to latency time (T L ) minus the reference time (TR), if (T L ) is greater than (TR), else immediately moving the magnetic head to the target position (P 1 ).

11. A hard disk drive (HDD) comprising:

a disk;

a magnetic head reading data from the disk;

a memory configured to store data read from the disk; and

a controller configured to receive a read command from a host device indicating a target sector on the disk, obtain a latency time (T L ) in relation to a movement time (T M ) and a search time (T S ), and read pre-fetch data from the disk at a current position (P C ) during the latency time (T L ) and store the pre-fetch data in the memory;

wherein the movement time (T M ) is defined as the time required to rotate the disk such that the target sector moves from an initial position (P 0 ) to a target position (P 1 ), and the search time (T S ) is defined as the time required to move a magnetic head in the HDD from the current position (P C ) to the target position (P 1 ), and

the controller is further configured to obtain the latency time (T L ) subtracting the movement time (T M ) from the search time (T S ) to obtain a subtractive result, and then subtracting the subtractive result from a rotational period time (TD), the rotational period time (TD) being defined as the amount of time required for the disk to complete one full revolution.

12. The HDD of claim 11 , wherein the controller is further configured to obtain the movement time (T M ) and the search time (T S ) and obtain the latency time (T L ) by subtracting the search time (T S ) from the movement time (T M ), where T M is greater than or equal to T S .

13. The HDD of claim 12 , wherein the search time (T S ) is obtained using a search time table in relation to a number of tracks the magnetic head must move from the current position (P C ) to the target position (P 1 ).

14. The HDD of claim 11 , wherein the controller is further configured to obtain the movement time (T M ) from an equation,

T

M

=

N

H

-

N

TS

N

S

⁢

T

D

,

wherein N TS is physical information data regarding the target sector, N H is physical information data regarding a sector associated with the current position (P C ) of the magnetic head, N S is the number of the sectors included in a target track associated with the target sector, and TD is a rotational period time required to complete one revolution of the disk.