Magnetic Disk Drive Frequency-Varied Recording Method
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Solution Overview
Problem
Magnetic disk drives face challenges in maintaining high recording density and quality due to the deterioration of assist recording techniques, such as Microwave-Assisted Magnetic Recording (MAMR) and Thermal-Assisted Magnetic Recording (TAMR), which affect the intensity of the recording magnetic field necessary for magnetization reversal.
Innovation Solution
A magnetic disk drive configuration that includes a magnetic disk, a magnetic head, and a signal processing circuit to generate a recording magnetic field with varying frequencies, using a base-recording data pattern to improve recording quality by adjusting the frequency of the recording magnetic field and recording data over this pattern to enhance magnetization reversal and reduce errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If assist recording techniques (MAMR/TAMR) are used to achieve high recording density, then recording density is improved, but recording quality deteriorates when the assist function deteriorates
Solution Approach 1:
The patent applies preliminary action by recording a base-recording data pattern before writing the actual data. This base pattern is recorded first to prepare the magnetic layer in advance, creating a favorable state for subsequent data writing. When assist function deteriorates, this pre-recorded base pattern ensures that the magnetic layer is already in an optimal state, preventing quality deterioration during actual data recording operations.
Solution Approach 2:
The patent utilizes parameter changes by varying the frequency of the recording magnetic field. The base-recording data pattern is recorded with a first frequency, and subsequent data is written with a second frequency that is higher than the first frequency. This frequency parameter change optimizes magnetization reversal characteristics and maintains recording quality even when assist recording techniques deteriorate.
2Speed
If high-frequency magnetic field is applied for magnetization reversal, then recording speed is improved, but errors increase when assist function deteriorates
Solution Approach 1:
The base-recording data pattern is recorded in advance to prepare the magnetic layer for subsequent high-speed data writing. This preliminary action ensures that the magnetic layer is in an optimal state before high-frequency recording occurs, reducing errors even when assist function deteriorates.
Solution Approach 2:
The patent changes the frequency parameter of the recording magnetic field, using a higher second frequency for writing data over the base pattern. This frequency optimization maintains effective magnetization reversal and reduces errors during high-speed recording operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves recording quality by reducing errors and maintaining high recording density, even when the assist function is deteriorated, by using a base-recording data pattern with a lower frequency and writing data with a higher frequency over it, thus maintaining the coercivity of the magnetic layer and improving data retention.
Implementation Method 1
a magnetic head configured to read/write data from/to the magnetic disk
Implementation Method 2
Microwave-Assisted Magnetic Recording (MAMR) is an assist recording technique for lowering the intensity of a recording magnetic field necessary for magnetization reversal by applying a high-frequency magnetic field to a magnetic disk
Implementation Method 3
Thermal-Assisted Magnetic Recording (TAMR) is an assist recording technique for lowering the intensity of the recording magnetic field necessary for magnetization reversal by heating a magnetic disk
Data Source
AI summary
According to one embodiment, there is provided a magnetic disk drive comprising a magnetic disk, a magnetic head configured to read/write data from/to the magnetic disk, a signal processing circuit configured to convert data to be recorded on the magnetic disk into a write signal, and to output the write signal to the magnetic head that generates a recording magnetic field corresponding to the write signal, and a recording control circuit configured to control the signal processing circuit and the magnetic head to record, in a target recording area of the magnetic disk, first data in the target recording area with a recording magnetic field having a first frequency, and to write, second data different from the first data over the first data with a recording magnetic field having a second frequency higher than the first frequency.