Self-Servo Write Process for Discrete Track Media
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Solution Overview
Problem
The existing servo writing process for disk drives is inefficient and costly due to the need for large, expensive servo writers, which increases manufacturing time as track density increases, creating a bottleneck in the disk drive manufacturing process.
Innovation Solution
A self-servo write process that enables a disk drive to write servo patterns independently using pre-printed position marks, allowing the drive to synchronize clocks and write servo data directly to the disk surface without an external servo writer, leveraging discrete track media to improve head positioning and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dedicated servo writer is used to write servo information to each concentric data track, then servo writing accuracy is improved, but manufacturing time increases and productivity decreases
Solution Approach 1:
The patent implements self-servo writing where the disk drive itself writes servo information to its own disk surfaces using its integrated write head, eliminating the need for external servo writers. The drive reads pre-formed position marks, processes this position information, and autonomously writes the servo wedges at the correct locations and orientations, enabling the system to serve its own servo writing needs
Solution Approach 2:
The patent makes the disk drive's write head perform multiple functions: it writes both user data and servo information, and the same head assembly performs both reading position marks and writing servo wedges. This multi-functionality eliminates dedicated servo writing equipment and integrates the servo writing capability into the standard disk drive operation
2Quantity of substance
If track density is increased to improve storage capacity, then data storage capability is improved, but servo writing time increases creating a manufacturing bottleneck
Solution Approach 1:
The patent uses pre-formed position marks that are created on the disk surface before the disk is installed in the drive. These position marks serve as pre-prepared reference information that the drive uses to determine where to write servo wedges, eliminating the time-consuming process of writing servo information track-by-track at high densities
3Stability of the object's composition
If a large, massive granite base and precision fixtures are used in the servo writer, then servo writing stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The disk drive uses its own integrated read-write head assembly to perform servo writing, eliminating the need for external servo writers with granite bases and precision fixtures. The drive's existing positioning and control systems are leveraged to achieve the necessary stability and precision for servo writing
Solution Approach 2:
The patent combines the servo writing function with the disk drive's existing read-write head and control systems. The same actuator arm, voice coil motor, and control electronics that position the head for data operations are used to position the head for servo writing, merging multiple functions into a single integrated system
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 reduces manufacturing time and costs by enabling the disk drive to perform self-servo writing, improving head positioning accuracy and tolerance, and extending magnetic recording capabilities beyond continuous media.
Implementation Method 1
a read-write head, such as a read-write head, retrieves and records data on a magnetic layer of a rotating disk
Implementation Method 2
When retrieving data, magnetic field variations are converted into an analog electrical signal
Data Source
AI summary
Systems and techniques relating to control of magnetic devices are disclosed. A described technique includes receiving a waveform via a head about a recording medium which includes data tracks and servo regions, detecting a servo region based on the waveform becoming an alternating signal, which is indicative of the head's path over discrete radially arranged magnetic strips in the servo region; performing a frequency synchronization of a read clock based on the detection to establish a frequency lock; performing a phase synchronization of the read clock to align a phase of the read clock with respect to acquired samples of the alternating signal; performing a synchronization of a write clock based on a write of a test sequence to the medium, the write clock being responsive to the frequency lock and the read clock; and writing, using the synchronized write clock, data to the medium for servo control.