Tape Drive Data Recovery via Multi-Read ECC Accumulation
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Solution Overview
Problem
Conventional tape drive systems face challenges in timely data retrieval due to incomplete data recovery during error correction processes, where ECC methods fail to recover data blocks with missing bytes, leading to unrecoverable data.
Innovation Solution
A method and apparatus that perform multiple read operations to accumulate a minimum number of data bytes necessary for ECC, combining recovered data from each attempt to ensure successful error correction, using a read/write controller with a data protect component to manage and combine data bytes across multiple reads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ECC error correction is performed on tape data, then data errors can be corrected, but data blocks with missing bytes cannot be recovered
Solution Approach 1:
The system performs preliminary read operations to accumulate sufficient data bytes before attempting ECC correction. By preparing the minimum required data bytes in advance through multiple read attempts, the system ensures that ECC correction can be successfully applied when sufficient data is available, preventing data loss that would occur with incomplete data blocks.
Solution Approach 2:
The patent transitions from a single-dimension approach (single read operation) to a multi-dimensional approach (multiple read operations accumulating data across different attempts). By gathering data bytes across multiple read operations, the system creates additional opportunities to recover complete data blocks that failed in individual read attempts, thereby improving overall data recovery capability.
2Reliability
If multiple read operations are performed to accumulate data bytes, then data recovery success rate improves, but data retrieval time increases
Solution Approach 1:
The system implements self-service by automatically performing multiple read operations and accumulating data bytes without external intervention. The read/write controller autonomously manages the accumulation process, monitoring when sufficient data bytes are available for ECC correction, and executing the necessary read operations to achieve successful data recovery, thereby balancing reliability improvement with time efficiency.
Solution Approach 2:
The patent replaces the mechanical tape movement system with an intelligent data accumulation and processing system. Instead of relying solely on physical tape repositioning and single-pass reading, the system uses software-controlled data byte accumulation across multiple reads, substituting mechanical operations with intelligent data processing to achieve both high recovery success rates and efficient time management.
3Reliability
If data bytes are accumulated across multiple read operations, then sufficient data for ECC is obtained, but system complexity increases
Solution Approach 1:
The read/write controller serves as an intermediary between the tape drive hardware and the ECC correction process. It manages the accumulation of data bytes across multiple read operations, tracking which bytes have been successfully read and determining when sufficient data is available for ECC correction. This intermediary layer simplifies the overall system by centralizing the complexity of multi-read coordination within a single controller component.
Data Source
AI summary
A method is disclosed. The method includes performing a first read operation at a tape drive, determining if a minimum number of data bytes have been recovered in the first read operation to perform error correcting codes (ECC), performing a second read operation if the minimum number of data bytes to perform ECC have not been recovered, determining if a minimum number of data bytes have been recovered in the second read operation to perform ECC, combining the recovered data bytes from the first read operation and the second read operation to form combined recovered data bytes, determining if a minimum number of data bytes are included in the combined recovered data bytes to perform ECC and performing ECC if the minimum number of data bytes are included in the combined recovered data bytes.