Parallel Self-Servo Write Circuitry for Faster HDD Servo Writing
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Solution Overview
Problem
The existing self-servo writing process in hard disk drives (HDDs) is inefficient and costly due to the lack of onboard hardware circuitry capable of supporting parallel self-servo writing with multiple read/write heads, leading to prolonged manufacturing times and increased costs.
Innovation Solution
A data storage device with control circuitry that enables parallel self-servo writing using two heads, each with multiple read elements, allowing simultaneous servo pattern writing on multiple storage medium surfaces by processing read signals in parallel and adjusting head positions based on error signals to meet tolerance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If specialized control circuitry is added to support parallel self-servo writing, then productivity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The control circuitry is designed to perform multiple functions: it controls both parallel self-servo writing operations and normal data read/write operations. The same read channels, write channels, and controller resources are shared between these two modes of operation, eliminating the need for dedicated specialized circuitry and reducing overall device complexity while maintaining improved productivity during self-servo writing
Solution Approach 2:
The patent merges the self-servo writing control functions with the existing data read/write control circuitry. By combining these functions into a unified control system that can operate in different modes, the patent avoids duplicating hardware resources and reduces the overall complexity of the control circuitry while still enabling parallel self-servo writing capability
2Loss of time
If parallel self-servo writing with multiple heads is implemented, then manufacturing time is reduced, but hardware cost increases
Solution Approach 1:
The existing read/write heads and their associated read channels and write channels are made multi-functional, serving both normal data operations and self-servo writing operations. This eliminates the need for separate dedicated hardware for self-servo writing, reducing hardware cost while still enabling parallel processing that reduces manufacturing time
Solution Approach 2:
The system uses its own existing hardware resources (read/write heads, channels, and controller) to perform self-servo writing without requiring external specialized equipment. The controller intelligently manages the self-servo writing process using available internal resources, reducing hardware costs while maintaining improved manufacturing efficiency
3Productivity
If onboard hardware circuitry for parallel self-servo writing is added, then productivity is improved, but manufacturing cost increases
Solution Approach 1:
The control circuitry is designed to perform multiple functions: it controls both parallel self-servo writing operations and normal data read/write operations. The same read channels, write channels, and controller resources are shared between these two modes of operation, eliminating the need for dedicated specialized circuitry and reducing overall device complexity while maintaining improved productivity during self-servo writing
Solution Approach 2:
The patent merges the self-servo writing control functions with the existing data read/write control circuitry. By combining these functions into a unified control system that can operate in different modes, the patent avoids duplicating hardware resources and reduces the overall complexity of the control circuitry while still enabling parallel self-servo writing capability
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 improving hardware efficiency, enabling faster and more reliable servo track writing on multiple surfaces, thus enhancing the overall performance and reliability of data storage devices.
Implementation Method 1
a first plurality of read elements, and each read element of the first plurality of read elements is configured to generate a corresponding read signal responsive to the first storage medium surface
Implementation Method 2
write, responsive to the first position relative to a first self-servo write reference spiral being within a first error tolerance value, a servo pattern at the first head
Data Source
AI summary
Example circuits, data storage devices, and methods to provide parallel self-servo write in a data storage device are described. The data storage device may include multiple heads actuated over respective surfaces of storage media and at least two preamplifiers and read paths to a channel circuit. Control circuitry may select heads connected through different preamplifiers for parallel self-servo write and receive read signals from the selected heads in parallel. These read signals, which may be based on self-servo write reference spirals previously written to the storage media, may be used to determine respective position error signals for the two heads and control their respective positions with corresponding control signals to a shared voice control motor and respective micro and/or milli actuators on the arms supporting the heads.