Dual-Read Element Shock Confirmation for Disk Drive Write Abort
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Solution Overview
Problem
Existing disk drives face challenges in accurately positioning the head over servo tracks due to corrupted servo bursts, leading to unnecessary write aborts and increased manufacturing time, especially when dealing with a large number of servo tracks.
Innovation Solution
The implementation of a dual-read element system, where a secondary read element confirms shock events and adjusts position error signals to prevent write aborts, and the use of multiple read elements with varying radial offsets to enhance servo control and multi-signal processing, allowing for more accurate head positioning and data recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single read element is used to read servo bursts for head positioning, then the device complexity is low, but measurement precision deteriorates due to corrupted servo bursts leading to inaccurate position error signals
Solution Approach 1:
The patent applies local quality by having two read elements with different radial offsets read different servo bursts locally. The first read element reads first servo bursts at one radial position while the second read element reads second servo bursts at a different radial position. This allows each read element to independently assess servo burst quality at its local position, and the system can selectively rely on readings from the element with better signal quality, thereby improving measurement precision without requiring a completely complex system architecture.
Solution Approach 2:
The patent uses an intermediary approach by introducing a secondary read element as a mediator to confirm shock events and validate position error signals. When the first read element detects a potential shock event or corrupted servo burst, the second read element acts as an intermediary to verify whether the event is real or an artifact. This intermediary validation mechanism improves measurement precision by filtering out false positives while adding only moderate system complexity.
2Reliability
If corrupted servo bursts trigger write aborts to ensure data integrity, then reliability improves, but productivity deteriorates due to increased manufacturing time and unnecessary aborts
Solution Approach 1:
The patent implements feedback by using the second read element to provide confirmation feedback before triggering a write abort. When the first read element detects a potential shock event or servo burst corruption, the system does not immediately abort the write operation. Instead, it seeks feedback from the second read element to confirm whether the event is genuine. This feedback mechanism reduces unnecessary write aborts caused by false detections, thereby improving productivity while maintaining reliability through confirmed error detection.
Solution Approach 2:
The patent applies preliminary action by performing a preliminary check with the second read element before committing to a write abort. Rather than immediately aborting when the first read element detects potential corruption, the system preliminarily validates the detection using the second read element's independent measurement. This preliminary validation action prevents premature aborts, allowing more write operations to complete successfully and improving manufacturing throughput while still ensuring data integrity when corruption is confirmed.
3Reliability
If multiple read elements with radial offsets are implemented to confirm shock events, then reliability improves by reducing false write aborts, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the shock event detection function across two separate read elements with different radial offsets. Instead of using a single complex detection mechanism, the system segments the detection task: the first read element performs initial detection while the second read element performs confirmation. This segmentation improves reliability by reducing false positives through independent verification, while the modular nature of adding separate read elements keeps the increase in device complexity manageable and structured.
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 unnecessary write aborts, improves head positioning accuracy, and decreases manufacturing time by confirming shock events and compensating for corrupted servo bursts, while maintaining multi-signal processing capabilities across different radial locations.
Implementation Method 1
a head connected to a distal end of an actuator arm which is rotated about a pivot by a voice coil motor (VCM) to position the head radially over the disk
Implementation Method 2
first servo data in a first servo track is read using a first read element to generate a first read signal
Data Source
AI summary
A data storage device is disclosed comprising a first disk surface comprising a plurality of servo tracks, a first head actuated over the first disk surface, wherein the first head comprises a first read element, and a second read element. During a write operation first servo data in a first servo track is read using the first read element to generate a first read signal, and the first head is servoed over the first servo track based on the first read signal while writing data to the first disk surface. Second servo data is read using the second read element to generate a second read signal, and the write operation is aborted when the first read signal indicates a shock event is affecting the servoing of the first head and the second read signal confirms the shock event.