HDD LBA Remapping Initialization Using On-the-Fly Mapping Units
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Solution Overview
Problem
The conventional initialization process following an LBA remapping operation in hard disk drives (HDDs) is time-consuming, taking days to complete due to the need to write a background data pattern to every remapped LBA, which does not keep pace with increasing HDD storage capacities.
Innovation Solution
A method that initializes aggregated groups of LBAs, known as mapping units, 'on the fly' by writing data to physical locations and generating background data patterns as needed, eliminating the need for a full HDD pack write, and using validity bits to track initialization status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full pack write is performed to initialize all remapped LBAs, then data integrity is ensured, but initialization time becomes excessively long
Solution Approach 1:
The patent applies preliminary action by pre-writing background data patterns to physical locations before LBA remapping operations. When LBAs are remapped, the controller checks whether the target physical location has been pre-initialized. If yes, the LBA is immediately available without requiring a full pack write, thus ensuring data integrity while dramatically reducing initialization time.
Solution Approach 2:
The patent implements partial action by performing pack write operations only on portions of the media that will be affected by remapping, rather than writing to every LBA. The controller identifies which physical locations need initialization based on the remapping operation, and only pre-writes background patterns to those specific locations, reducing overall initialization time while maintaining data integrity for remapped LBAs.
2Reliability
If conventional initialization procedures are used after LBA remapping, then all remapped LBAs are properly initialized, but the process takes days to complete
Solution Approach 1:
The system performs preliminary initialization of physical locations before remapping operations occur. The controller pre-writes background data patterns to physical sectors that are anticipated to be remapped, so when the remapping occurs, these LBAs are already initialized and immediately available for use, eliminating the need for lengthy post-remapping pack writes.
Solution Approach 2:
The patent segments the initialization process by dividing the media into regions that will be affected by remapping and those that won't. The controller identifies and separates these regions, applying pack write operations only to the affected segments. This segmentation allows the system to maintain complete initialization of remapped LBAs while avoiding unnecessary writes to unaffected areas, thereby improving initialization speed.
3Reliability
If the host system waits for full initialization after LBA remapping, then data access reliability is ensured, but system productivity is reduced
Solution Approach 1:
The controller performs preliminary initialization of physical locations before the host system needs to access remapped LBAs. By pre-writing background patterns to anticipated remap targets, the system ensures that when remapping occurs, the host can immediately access initialized LBAs without waiting for post-remapping pack writes, thus maintaining reliability while improving system throughput.
Solution Approach 2:
The controller acts as an intermediary between the host system and the storage media during remapping operations. It manages the initialization process independently by pre-writing to physical locations, then coordinates with the host to ensure reliable data access. This intermediary role allows the host to maintain productivity while the controller ensures data access reliability through proactive initialization management.
Data Source
AI summary
A data storage device comprises recording heads and magnetic recording media. An initialization process is performed following a logical block address (LBA) remapping operation that remaps LBAs to physical locations on the media. The initialization process comprises initializing a write target LBA in response to a write command by writing data to a physical location on the media that is mapped to the write target LBA, receiving a read command to read data from a read target LBA, reading and returning data from the physical location on the magnetic recording media that is mapped to the read target LBA if the read target LBA has been initialized, and generating and returning a background data pattern if the read target LBA has not been initialized.