Hard Disk Drive Servo Wedge Data Storage Capacity
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Solution Overview
Problem
The increasing number of servo wedges on magnetic recording media reduces the available area for user data, as more space is dedicated to servo data, leading to a decrease in storage capacity in data storage devices like hard disk drives.
Innovation Solution
Overwriting servo data with user data in multiple servo wedges within a first data track on a magnetic recording medium, allowing for increased storage capacity by utilizing firmware to control the magnetic writer to write user data in servo sectors, thereby optimizing the use of space on the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of servo wedges on magnetic recording media is increased to improve positioning accuracy, then positioning precision is improved, but the available area for user data is reduced
Solution Approach 1:
The patent applies multi-functionality by enabling servo wedges to serve dual purposes: maintaining their original positioning function while simultaneously storing user data. The system identifies and utilizes unused or underutilized servo wedge regions to store additional user data, allowing the same physical space to fulfill both servo control and data storage functions, thereby resolving the contradiction between positioning accuracy and storage capacity
Solution Approach 2:
The patent changes the parameter of data density in servo wedge regions by implementing write-once-read-many (WORM) data storage. By modifying the recording characteristics and utilizing previously unused servo wedge capacity, the system increases the effective storage density without altering the physical structure or reducing positioning accuracy, thus resolving the space allocation conflict
2Quantity of substance
If user data is written in servo wedges to increase storage capacity, then storage capacity is improved, but the ability to position read/write heads accurately is impaired
Solution Approach 1:
The patent applies segmentation by dividing the servo wedge structure into distinct functional zones: critical servo data regions that maintain positioning accuracy and unused or underutilized regions that store user data. By segmenting the servo wedge functionality and selectively writing user data only to appropriate regions, the system preserves positioning accuracy while increasing storage capacity
Solution Approach 2:
The patent applies local quality by assigning different functions to different parts of the servo wedge structure. Critical servo sectors maintain their original positioning function with high-quality recording, while other portions of the servo wedges are designated for user data storage with appropriate WORM characteristics, allowing each region to optimize its specific function without compromising the other
3Extent of automation
If firmware is used to control the magnetic writer to write user data in servo sectors, then device complexity is improved through software control, but manufacturing complexity increases
Solution Approach 1:
The patent applies self-service by implementing a firmware-based system that automatically identifies suitable servo wedge regions for user data storage and manages the writing process. The firmware autonomously handles the complexity of determining which servo wedges can accommodate user data without compromising positioning, eliminating the need for complex manufacturing process modifications and simplifying production
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 effectively increases the storage capacity of data storage devices by reallocating space from servo data to user data, while maintaining the ability to position read/write heads accurately, albeit with potential impairments in writing data within desired tracks.
Implementation Method 1
an integrated circuit includes firmware for causing a magnetic writer to write, via emitted magnetic fields, non-servo data in multiple servo wedges within a first data track on a magnetic recording medium
Data Source
AI summary
A hard disk drive includes a magnetic writer and a magnetic recording medium, which includes data tracks with user data sections positioned between servo wedges. The servo wedges each can include multiple servo sectors. The hard disk drive also includes circuitry programmed to cause the magnetic writer to write user data to the multiple servo sectors in multiple servo wedges.