Data Storage Apparatus Synchronization Clock Adjustment
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Solution Overview
Problem
Conventional magnetic disk devices face challenges in achieving high synchronization accuracy during data writing on patterned media without increasing the size of the synchronization area, which compromises format efficiency.
Innovation Solution
A data storage apparatus with a medium having alternating synchronization marks and data blocks, utilizing a processor to generate a write/read clock that adjusts for speed variations by calculating time differences between data blocks, allowing for synchronized data writing and reading without increasing the number of synchronization marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the predetermined number of sequence bits is reduced to improve synchronization accuracy, then synchronization accuracy is improved, but the synchronization area is increased and format efficiency is reduced
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing timing correction values for each data block based on measured head position variations. These correction values are prepared in advance and applied during the write operation to compensate for timing deviations, eliminating the need for extensive synchronization areas while maintaining high synchronization accuracy.
Solution Approach 2:
The patent changes the parameter of write clock timing by dynamically adjusting the write timing for each data block based on measured head position variations. Instead of using a fixed write clock, the system calculates timing corrections for each block and applies them individually, achieving high synchronization accuracy without requiring a large synchronization area.
2Measurement precision
If the synchronization area is increased to improve synchronization accuracy, then synchronization accuracy is improved, but the recording capacity is reduced
Solution Approach 1:
The system performs preliminary measurement of head position variations and pre-calculates timing correction values for each data block before the actual write operation. This preliminary action enables accurate synchronization with minimal synchronization area, preserving maximum recording capacity.
Solution Approach 2:
The system uses the existing synchronization marks and head position measurement capabilities to self-correct timing deviations for each data block. By leveraging the system's own measurement resources, it achieves high synchronization accuracy without requiring additional dedicated synchronization area, thus maintaining recording capacity.
3Measurement precision
If the write clock is continuously adjusted for each data block to improve synchronization accuracy, then synchronization accuracy is improved, but the device complexity is increased
Solution Approach 1:
The patent reduces device complexity by performing all complex calculations in advance. The timing correction values for each data block are pre-calculated and stored during a measurement phase, so that during normal operation, the system only needs to retrieve and apply these pre-computed values, significantly simplifying the real-time control logic.
Solution Approach 2:
The system creates a copy of the ideal timing information by measuring actual head position variations and generating correction values that represent the deviation from ideal timing. These correction copies are then applied to the write clock for each data block, enabling accurate synchronization without requiring complex real-time calculation mechanisms.
Data Source
AI summary
A data storage apparatus includes: a medium for storing data having synchronization marks and data blocks, the synchronization mark and the data block being allocated alternately in the circumference direction of the medium; a head writing data into or reading out data from the medium; and a processor for executing a process including: reading out synchronization marks, measuring time for the head to pass through each of the data blocks based on signals read out from each of the synchronization marks in the circumference direction, generating write/read clock for each of the data blocks, which is continuously changing in speed, by calculating difference in time for the head to pass through the each one of the data blocks and its adjacent one of the blocks on the basis of the time measured, and writing data into or reading out data from the medium in synchronization with the write/read clock.