High-density recording method for hard disk drives and a pre-amplifier circuit suitable for use with same

Abstract

A magnetic recording method is provided where ternary data is recorded on a magnetic recording medium by forming a first area that corresponds to a first value of the data and in which a first magnetization state is continued at least during the minimum write width. A second area that corresponds to a second value of the data in which a second magnetization state is oppositely magnetized as compared with the first magnetization state is continued at least during the minimum write width. A third area that corresponds to a third value of the data in which the magnetic intensity detected by the read head corresponds to a “0.” Accordingly, the ternary data can be recorded using the characteristic that a signal having a width narrower than the detection width of the read head is not detected by the read head.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a conventional HDD;

FIG. 2 is a schematic diagram for explaining a conventional perpendicular recording method;

FIG. 3 is a graph showing a correlation between the detection width of a read head and the minimum write width;

FIGS. 4A through 4G are diagrams for explaining a write/read process in a conventional HDD;

FIGS. 5A through 5C are diagrams for explaining a recording method according to an embodiment of the present invention;

FIGS. 6A through 6F are diagrams for explaining a write current in the recording method according to an embodiment of the present invention;

FIG. 7 is a circuit diagram of a pre-amplifier suitable for the recording method according to an embodiment of the present invention; and

FIG. 8 is a block diagram of a control system for controlling an HDD according to an embodiment of the present invention.

Claims

1. A magnetic recording method for recording data on a magnetic recording medium, wherein the data has a minimum write width corresponding to at least a read detection width of a read head, said method comprising: recording ternary data in a first area on said magnetic recording medium corresponding to a first data value, said data recorded in the first area having a first magnetization state which continues at least during said minimum write width.recording ternary data in a second area on said magnetic recording medium corresponding to a second data value, said data recorded in the second area having a second magnetization state which continues at least during said minimum write width, said second magnetization state oppositely magnetized from said first magnetization state; andrecording ternary data in a third area on said magnetic recording medium corresponding to a third data value, said data recorded in said third area having a “0” value magnetic intensity detected by said read head.

2. The method of claim 1, wherein said third area is formed by alternating the first magnetization state and the second magnetization state, each of said areas having a write width narrower than the minimum write width.

3. The method of claim 1, wherein said third area is formed by alternating the first magnetization state and the second magnetization state, each having a write width narrower than ½ the minimum write width.

4. The method of claim 1, wherein said third area is formed by alternating the first magnetization state and the second magnetization state, each having a write width narrower than ¼ the minimum write width.

5. The method of claim 1, wherein the intensity of a mean magnetic flux detected by said read head in said third area is 0.

6. The method of claim 1, wherein the magnetic recording medium is a perpendicular magnetic recording medium.

7. A magnetic recording method for recording data by changing magnetization directions of a magnetic recording medium, said method comprising: recording ternary data in a first area on said recording medium magnetized for the intensity of magnetic flux detected by a read head from the magnetic recording medium to be −1;recording ternary data in a second area on said recording medium magnetized for the intensity of magnetic flux detected by the read head from the magnetic recording medium to be 1; andrecording ternary data in a third area on said recording medium magnetized for the intensity of magnetic flux detected by the read head from the magnetic recording medium to be 0.

8. A pre-amplifier circuit applying a write current to a write head to record data having a minimum write width corresponding to at least a detection width of a read head, the pre-amplifier circuit comprising: a direct current (DC) signal generator generating a DC signal having a predetermined amplitude;a first switch circuit for applying the DC signal from said DC generator to the write head in a first direction during a period in which the data to be recorded has a first value;a second switch circuit for applying the DC signal from said DC generator to the write head in a second direction opposite to the first direction during a period in which the data to be recorded has a second value;a high frequency signal generator generating a high frequency signal having a higher frequency than a write frequency corresponding to the minimum write width; anda third switch circuit for applying the high frequency signal to the write head during a period in which the data to be recorded has a third value.

9. The pre-amplifier circuit of claim 8, wherein the first, second and third switch circuits operate according to the value of the data.

10. A magnetic recording apparatus comprising: a write head generating a magnetic field for magnetizing a magnetic recording medium; anda pre-amplifier circuit having a direct current (DC) signal generator which generates a DC signal having a predetermined amplitude, and an alternative current (AC) signal generator, which generates a high frequency signal having a higher frequency than a write frequency corresponding to a write width of a read head, and supplying a write current corresponding to data to be recorded by the write head, wherein said pre-amplifier circuit applies the DC signal to the write head in a first direction during a period in which the data to be recorded on the magnetic recording medium has a first value, said pre-amplifier circuit applying the DC signal to the write head in a second direction during a period in which the data to be recorded has a second value, and said pre-amplifier circuit applying the high frequency signal to the write head during a period in which the data to be recorded has a third value.

11. The magnetic recording apparatus of claim 10, wherein said write head generates a magnetic field perpendicular to a surface of said magnetic recording medium.