Distributed Track Checksums for Reliable Data Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In digital data storage (DDS) formats, double C3 error correction is unreliable when both tracks of a frame are completely unreadable, as track checksum information is lost, preventing verification and leading to potential mis-correction during data recovery.
Innovation Solution
Storing track checksums in multiple tracks across the data group, rather than just within the same frame, ensures that checksum verification can occur even if one or both tracks in a frame are unreadable, by distributing checksum data throughout the group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If track checksums are stored only in the same frame's sub code, then storage space is optimized, but data integrity verification fails when both tracks of a frame are unreadable
Solution Approach 1:
The patent extends the storage location of checksums from a single frame (two-dimensional constraint) to multiple frames across the data group (three-dimensional distribution). By storing checksums in tracks belonging to different frames rather than confining them to the same frame, the system creates redundancy across multiple dimensions of the data structure, ensuring that checksum information remains accessible even when individual frames are corrupted.
Solution Approach 2:
The patent applies different storage strategies to different types of data within the data group. Checksum information is distributed to specific tracks in different frames based on their reliability and positional characteristics, rather than uniformly storing all checksums in the same location. This localized quality approach ensures that critical verification data is placed in positions most likely to survive corruption events.
2Reliability
If checksums are replicated across multiple frames, then verification reliability improves, but storage overhead increases
Solution Approach 1:
The patent makes the data group structure multi-functional by serving dual purposes: the primary function of storing user data and the secondary function of distributing checksum information for verification. The same data group that contains the original data also contains the checksum information needed for verification, eliminating the need for separate dedicated checksum storage areas and achieving space efficiency through functional consolidation.
Solution Approach 2:
The patent merges the data storage function and checksum storage function into a unified data group structure. Instead of separating checksum information into dedicated overhead areas, the system combines both functions within the same data group, allowing checksums to be stored in tracks that are part of the normal data group composition rather than requiring additional separate storage resources.
3Productivity
If double C3 correction is applied to correct unreadable tracks, then data recovery capability improves, but mis-correction risk increases without verified checksums
Solution Approach 1:
The patent implements a feedback mechanism where checksum information from different frames is used to verify the accuracy of C3 correction operations. After attempting to correct unreadable tracks, the system retrieves checksums from tracks in different frames and compares them against the corrected data. This feedback loop ensures that corrections are validated before accepting the recovered data, preventing mis-correction from propagating undetected errors.
Solution Approach 2:
The patent performs preliminary retrieval of checksum information from different frames before attempting C3 correction. By having the verification checksums ready in advance from alternative locations, the system can immediately verify correction results without delay, ensuring that the correction process is both efficient and accurate. This preliminary preparation of verification data enables rapid validation of correction outcomes.
Data Source
AI summary
A method of processing data comprising arranging data into a data group comprising a plurality of sub groups each said subgroup comprising a plurality of columns; for each column, determining at least one checksum data of said column; and for each column, storing the checksum data of that column within at least one said subgroup of the group, other than the subgroup to which said column belongs.