SMR HDD Write Head Overwrite Threshold Control
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Solution Overview
Problem
Existing methods for wiping out sensitive data from large capacity hard disk drives (HDDs) are time-consuming, as they require multiple passes of the write head, especially in Shingled Magnetic Recording (SMR) HDDs where the larger write head can inadvertently overwrite adjacent tracks, leading to inefficiencies.
Innovation Solution
A method and device that control the write head to overwrite a threshold number of tracks simultaneously, skipping over adjacent tracks that have already been overwritten, thereby reducing the number of passes needed to completely overwrite the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the write head overwrites tracks one at a time in SMR HDDs, then data security is ensured, but the overwrite process takes substantially long time
Solution Approach 1:
The patent segments the overwrite process into multiple passes, where each pass overwrites a portion of tracks. By dividing the medium into different track groups and performing sequential passes with different starting positions, the system achieves complete overwriting while maintaining data security through controlled write head positioning.
Solution Approach 2:
The patent implements periodic action by repeating the overwrite process multiple times with different starting track positions. Each pass overwrites tracks starting from a different position, and by periodically repeating this process with offset starting points, the system ensures all tracks are eventually overwritten without requiring the write head to cover every single track in each pass.
2Productivity
If the write head covers multiple tracks simultaneously in SMR HDDs, then overwrite speed increases, but adjacent tracks may be inadvertently overwritten causing data loss
Solution Approach 1:
The patent applies dynamics by making the write head position and track selection dynamic rather than static. The system adjusts which tracks are overwritten in each pass based on the starting position and uses multiple dynamic passes to cover all tracks. This dynamic approach allows the write head to efficiently cover multiple tracks per pass while ensuring complete coverage through adaptive positioning across multiple operations.
3Reliability
If multiple passes are performed to overwrite the entire medium, then complete data wiping is achieved, but the process becomes time-consuming and inefficient
Solution Approach 1:
The patent segments the medium into different track groups and divides the overwrite process into multiple passes, each handling a specific segment. By organizing tracks into groups and systematically working through them in sequential passes with different starting positions, the system achieves complete data wiping while optimizing the number of passes required compared to traditional methods.
Solution Approach 2:
The patent uses periodic action by repeating the overwrite process multiple times with different starting track positions. Each periodic pass overwrites a portion of the tracks, and by systematically repeating this process with offset starting points, the system ensures complete coverage of all tracks while reducing the total number of passes needed compared to conventional single-pass-per-track methods.
Data Source
AI summary
A command is received to overwrite a medium. A threshold number of tracks is overwritten using a write head, in response to the command. The write head is then moved based on the threshold number. The threshold number is greater than one.