Dual-Surface RRO Write Using Parallel Read Channels
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Solution Overview
Problem
The existing methods for writing repeatable run-out (RRO) data to multiple surfaces of a magnetic storage device are time-consuming and costly, as they typically require days or weeks due to the limitations of single read-data and write-data channels operating on one surface at a time, which is inefficient for manufacturing high-performance disk drives.
Innovation Solution
Implementing a method that uses two read channels to detect servo signals on multiple surfaces and generate positioning signals for writing RRO data using a single write data channel, allowing concurrent writing on both surfaces, thereby reducing the time and cost by leveraging two-dimensional magnetic recording technology and micro-actuators for precise head positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single read-data and write-data channels are used to operate on one surface at a time, then device complexity is reduced, but productivity deteriorates due to time-consuming operations spanning days or weeks
Solution Approach 1:
The patent divides the read channel resources into multiple independent read channels (first read channel and second read channel), allowing simultaneous operation on different surfaces. This segmentation enables parallel processing of servo signal detection and RRO data writing across multiple surfaces, directly resolving the productivity-device complexity contradiction by trading controlled channel multiplication for significant speed improvement.
Solution Approach 2:
The patent transitions from single-surface sequential operation to multi-surface parallel operation by adding the surface dimension to the operation space. By utilizing multiple read channels that can simultaneously access different surfaces while sharing a common write channel, the system expands from one-dimensional sequential processing to multi-dimensional parallel processing, achieving near-doubling of writing speed.
2Productivity
If multiple read channels are implemented for concurrent surface operation, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent merges the write channel resources by implementing a single shared write channel that serves multiple surfaces, while maintaining separate read channels for each surface. This merging approach reduces device complexity by consolidating write resources while preserving read parallelism, effectively resolving the productivity-complexity contradiction through asymmetric resource sharing.
Solution Approach 2:
The write channel is designed with multi-functionality to serve multiple surfaces sequentially, while read channels maintain dedicated surface access. This universality in the write channel allows it to be shared across surfaces without compromising the parallel read operations, enabling productivity improvement with minimal complexity increase.
3Loss of time
If RRO data is written to multiple surfaces sequentially, then device complexity is minimized, but loss of time increases to days or weeks
Solution Approach 1:
The patent implements preliminary action by having multiple read channels simultaneously detect servo signals and prepare positioning information for multiple surfaces before the actual RRO data writing begins. This preliminary parallel preparation phase enables the subsequent write phase to proceed much faster, as the write channel receives pre-processed data from multiple surfaces concurrently rather than sequentially.
Solution Approach 2:
The patent maintains continuity of useful action by enabling both read channels to operate continuously and simultaneously on different surfaces throughout the servo signal detection phase. This continuous parallel operation eliminates idle time between surfaces that would exist in sequential operations, directly reducing the total operation duration from days or weeks to a fraction of that time.
4Productivity
If concurrent writing on multiple surfaces is enabled, then productivity is enhanced, but manufacturing precision requirements increase for head positioning
Solution Approach 1:
The patent implements feedback mechanisms where each read channel detects servo signals from its respective surface and generates positioning signals that are processed to determine precise head position. This feedback loop for each surface allows the system to maintain high manufacturing precision during concurrent operations by continuously monitoring and adjusting head positions based on actual servo signal readings from each surface.
Solution Approach 2:
The patent introduces positioning signal processing as an intermediary step between servo signal detection and RRO data writing. The positioning signals generated from servo signal processing act as mediators that translate raw servo data into precise head position information, enabling the system to maintain manufacturing precision while operating multiple surfaces concurrently through the intermediary positioning calculation layer.
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 nearly halves the time required for self-servo-write and RRO-write operations, enhancing manufacturing efficiency and reducing costs by enabling simultaneous writing on multiple surfaces with improved precision and alignment of read/write heads.
Implementation Method 1
detecting, with a first read head of the storage device, using a first read channel, a servo sync mark on a first track on a first storage medium surface of the storage device
Implementation Method 2
writing first repeatable run-out data to servo wedges of the first track according to the first positioning signals, and second repeatable run-out data to servo wedges of a second track
Data Source
AI summary
A method for writing repeatable run-out (RRO) data, to surfaces of a rotating magnetic storage medium in a storage device having two read channels, includes detecting, with a first head, using a first read channel, a servo sync mark (SSM) on a first track on a first surface, establishing a recurring servo-gating signal at a successive fixed interval from the SSM, detecting, with the first head, servo signals from the first track on occurrence of the recurring servo-gating signal, processing the servo signals from the first track, to generate first positioning signals for positioning the first head relative to the first track, following a similar procedure with a second read channel having a second head to generate second positioning signals for the second read head, and writing first and second RRO data to servo wedges of the first and second tracks according to the respective positioning signals.