Magnetic Disk Drive Data Refresh Using Adjacent Spare Tracks
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Solution Overview
Problem
Magnetic disk drives face efficiency issues during data refreshment due to power interruptions, which can lead to data loss and increased operation time when using a spare track on the disk instead of RAM, as it requires additional seek operations and longer write times.
Innovation Solution
Implementing a data refreshment process where data from a target track is written to an adjacent spare track, allowing for high-speed movement and reducing the need for intermediate write operations, thus minimizing the impact of power interruptions and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is written to a spare track on the disk instead of RAM during refreshment, then data loss is prevented during power interruptions, but operation time increases due to additional seek operations and longer write times
Solution Approach 1:
The patent introduces an intermediary storage area (spare track) on the disk to temporarily hold data during the refreshment process. This mediator allows the system to complete the write operation to the target track even if power is interrupted, preventing data loss while managing the performance overhead through careful track selection and operation optimization.
2Quantity of substance
If track pitch is reduced to increase track density, then storage capacity per disk surface is increased, but data write operations increasingly degrade adjacent track data due to leakage fields
Solution Approach 1:
The patent converts the harmful leakage field effect into a beneficial refreshment opportunity. By monitoring write operations and identifying tracks that have accumulated sufficient write counts, the system proactively refreshes these tracks by rewriting their data, thereby correcting degradation caused by leakage fields from adjacent tracks and maintaining data integrity despite high track density.
3Reliability
If data is read from target track and written back to the same track for refreshment, then data degradation is recovered, but data loss occurs if power is interrupted during the write operation
Solution Approach 1:
The patent performs a preliminary write operation to a spare track before completing the refreshment to the target track. This preliminary action creates a safety checkpoint: if power is interrupted during the subsequent write to the target track, the data can be recovered from the spare track, preventing data loss while ensuring successful refreshment.
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 prevents data loss during power interruptions and reduces the refreshment process's efficiency degradation by allowing high-speed head movement and eliminating the need for intermediate write operations, thereby maintaining data integrity and reducing operational time.
Implementation Method 1
the width of distribution of write magnetic fields generated by the head during the data write
Data Source
AI summary
According to one embodiment, a disk has a set of tracks thereon. A controller performs refresh control for reading data by a head from a track on the disk to be refreshed and for writing the read data by the head to a spare track adjacent to the track from which the data has been read. The controller switches the track from which the data has been read to a new spare track after the writing.