Disk Drive Defect Margining via Extended Lists
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Solution Overview
Problem
Current disk drive manufacturing processes do not adequately account for defects during the verification testing, leading to potential failure in data storage devices due to insufficient margining around detected defects, which can result in reliability issues during usage.
Innovation Solution
The implementation of extended defect margining during burn-in testing, where a processor generates an extended defect list that includes detected media defects and additional margins, allowing user data areas to be shifted into a spare area to compensate for potential defect growth, thereby increasing disk drive reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If minimal area corresponding to each detected defect is removed from data storage, then manufacturing cost is reduced, but disk drive reliability deteriorates due to potential defect spread during usage
Solution Approach 1:
The patent applies preliminary action by performing defect margining during burn-in testing before the disk drive is deployed. The system proactively identifies potential defect locations and creates margin zones in advance, preventing future defects from compromising data integrity. This early intervention allows minimal defect removal during manufacturing while ensuring reliability through pre-established safety margins.
Solution Approach 2:
The patent implements beforehand cushioning by creating extended margin zones around detected defects during burn-in testing. These margin zones act as protective buffers that prevent potential defect spread to adjacent data areas. The system establishes these protective zones in advance, allowing the use of minimal defect removal during manufacturing while guaranteeing reliability through pre-created protective barriers.
2Reliability
If extended defect margining is implemented during burn-in testing, then disk drive reliability is improved, but data storage capacity is reduced due to additional margin areas
Solution Approach 1:
The patent applies partial action by implementing defect margining selectively during burn-in testing only for disks that exhibit actual defects. Rather than applying extensive margining to all disks, the system performs targeted margining based on actual defect detection, creating margin zones only where necessary. This approach improves reliability through selective margining while minimizing the impact on overall storage capacity.
3Reliability
If disk defects are margined during verification testing, then disk drive reliability is improved, but testing time and complexity increase
Solution Approach 1:
The patent integrates defect margining into the burn-in testing process, performing margining operations during the existing burn-in period rather than adding separate testing phases. The system utilizes the burn-in testing time to scan for defects, generate margin lists, and create protective margin zones, thereby improving reliability without significantly extending the overall testing timeline.
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 enhances disk drive reliability by accounting for potential defect growth and ensuring that the disk drive can maintain data storage capacity and performance by utilizing spare areas to extend user data areas beyond initial defect margins.
Implementation Method 1
a head connected to a distal end of an actuator arm which is rotated by a pivot by a voice coil motor (VCM) to position the head radially over the disk
Implementation Method 2
Data is typically written to the disk by modulating a write current in an inductive coil to record magnetic transitions onto the disk surface
Implementation Method 3
the magnetic transitions are sensed by a read element (e.g., a magnetoresistive element) and the resulting read signal demodulated by a suitable read channel
Data Source
AI summary
A disk drive is disclosed that enables defect margining during disk drive burn-in testing. The disk drive comprises: a disk comprising a plurality of tracks; a head actuated over the disk; and a processor. The processor is configured to: perform disk drive burn-in testing to detect media defects; generate an initial defect list based upon detected media defects for sectors; generate an extended defect list that includes detected media defects and extended defect margins from the detected media defects; and utilize the extended defect list for burn-in, wherein a spare area of the disk allows for the detected media defects and the extended defect margins.