Ammonite Servo Pattern Writing in Heat-Assisted Magnetic Recording
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Solution Overview
Problem
The existing offline ammonite servo track writers exceed the continuous write time limit in heat-assisted magnetic recording (HAMR) technology due to the linear length of ammonite reference patterns, which can result in thermal changes to the disk surface during lengthy write times, necessitating a new pattern writing method that divides patterns into segments within the HAMR continuous write time limit.
Innovation Solution
An intermittent signal is applied to the write gate between the read/write channel and the read/write head, allowing the ammonite reference patterns to be written in segments that do not exceed the HAMR continuous write time, using a processor-executable instruction to generate a recording signal and move the read/write head across the disk in a spiral pattern, thereby avoiding adverse thermal effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If continuous writing is used to write the entire ammonite reference pattern, then writing completeness is achieved, but thermal changes occur on the disk surface due to exceeding the continuous write time limit
Solution Approach 1:
The continuous ammonite reference pattern writing is divided into multiple segments, each within the HAMR continuous write time limit. The write gate signal is modulated to enable writing only during specific time windows when the laser is off, creating discrete writing segments rather than continuous writing.
Solution Approach 2:
The write gate signal is applied periodically with a frequency that allows the laser to be off during writing intervals. This periodic modulation of the write gate creates alternating periods of writing and non-writing, ensuring the disk surface returns to ambient temperature between writing segments.
2Productivity
If the write gate is continuously enabled, then writing speed is maximized, but the HAMR continuous write time limit is exceeded causing thermal distortion
Solution Approach 1:
The write gate signal transitions from a static continuous state to a dynamic time-varying state. The write gate is dynamically enabled and disabled according to the laser's on/off cycles, optimizing the writing process to occur only during safe thermal conditions while maintaining overall writing efficiency.
3Device complexity
If the ammonite pattern is written in a single continuous pass, then manufacturing complexity is minimized, but the write time exceeds the HAMR limit requiring thermal management
Solution Approach 1:
The writing process maintains continuity by immediately resuming writing after each segment completes, without full stops. The write gate simply pauses during laser-on periods and resumes when the laser is off, keeping the writing action continuous from the perspective of the overall process while respecting thermal constraints.
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 method allows for the accurate and efficient writing of ammonite servo reference patterns within the HAMR continuous write time limit, ensuring precise placement and compatibility with existing hardware, enhancing areal density capacity without thermal distortion.
Implementation Method 1
heat-assisted magnetic recording
Data Source
AI summary
Technologies are described herein for writing servo reference patterns in a storage device implementing heat-assisted magnetic recording. A recording signal for the servo reference patterns is generated through a read/write channel to a read/write head of the storage device. The read/write head is moved across a recording surface of a disk in the storage device as the disk is rotated and an intermittent signal is applied to a write gate interposed between the read/write channel and the read/write head so that a maximum continuous writing time of the recording signal does not exceed a continuous write time limit of the storage device.