Auxiliary Read Head for Write Synchronization in Bit Patterned Media
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Solution Overview
Problem
Magnetic recording systems face challenges in maintaining precise synchronization and registration during the write process, particularly with bit patterned media, where missynchronization can lead to incorrect magnetization of data islands and potential data loss.
Innovation Solution
A method is introduced where sync information is read from a second magnetic disk surface using a read head on a different slider, allowing the write clock of the first slider to be adjusted based on this data, thereby ensuring accurate synchronization and inhibiting the write process if misregistration or off-track excursions exceed acceptable limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a read head on the same slider is used to read sync information during writing, then synchronization can be maintained, but noise from the write head interferes with the reading process
Solution Approach 1:
The system divides the read/write function into separate heads: a write head for writing data and a separate read head for reading sync information. This segmentation allows the read head to operate independently from the write head, avoiding noise interference while maintaining synchronization capability.
Solution Approach 2:
The patent uses an intermediary read head that reads sync information from the disk surface without being affected by write head noise. This intermediary component transfers synchronization data to the control system, enabling accurate timing reference without direct exposure to write head interference.
2Quantity of substance
If bit patterned media is used to increase data density, then higher data capacity is achieved, but precise registration and timing are required to prevent incorrect magnetization
Solution Approach 1:
The system continuously reads sync information from the disk using the read head and uses this feedback to adjust the write clock frequency and phase in real-time. This closed-loop feedback ensures precise registration between the write head and bit patterns, preventing incorrect magnetization while maintaining high data density.
Solution Approach 2:
The patent dynamically adjusts write clock parameters (frequency and phase) based on read sync information to maintain precise timing alignment. This parameter adjustment ensures that write pulses are applied at the correct moments to magnetize individual bits accurately on bit patterned media.
3Reliability
If the write clock is updated frequently to maintain synchronization, then data integrity is improved, but the system complexity increases
Solution Approach 1:
The system uses the disk surface itself to store sync information that automatically provides timing reference for write operations. The read head continuously reads this self-generated sync information, and the control system automatically adjusts the write clock without external intervention, maintaining data integrity through self-servicing synchronization.
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 enables frequent updating of the write clock frequency and phase without noise interference, enhancing data integrity and preventing data loss in bit patterned media systems by maintaining precise synchronization and preventing off-track excursions.
Implementation Method 1
A magnetoresistive sensor such as a GMR or TMR sensor can be employed for sensing magnetic fields from the rotating magnetic disk
Implementation Method 2
An electrically conductive write coil is wrapped around the write pole and induces a magnetic flux that magnetizes the write pole when a current is passed through the coil
Implementation Method 3
The slider flies over the surface of the disk on a cushion of this moving air
Data Source
AI summary
A method for recording data to a magnetic media while simultaneously reading sync and or servo data with reduced noise from the write head affecting the reading of the sync and or servo data. The invention records data using a write head of a first slider and reads the sync and or servo data from a read head located on a different slider that is facing a different disk surface than the first slider. In this way, magnetic or thermal noise from the write head does not affect the reading of the sync and or servo data.