XOR Buffer CRC Checking for Hard Disk Data Corruption Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing XOR buffer systems in hard disk controllers require additional space and cost due to the need for a parity bit to detect data corruption, making them larger and more expensive.
Innovation Solution
Implementing a CRC-based system within the XOR unit in the hard disk controller to detect data corruption in the XOR buffer, eliminating the need for a parity bit by using a CRC calculator to verify the integrity of the XOR result stored in the buffer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a parity bit is used to detect data corruption in the XOR buffer, then data integrity is protected, but the buffer size and cost increase
Solution Approach 1:
The patent changes the error detection parameter from a simple parity bit (1 bit) to a CRC value (typically 16 or 32 bits). Although CRC uses more bits, it provides superior error detection capability. The XOR buffer stores both the data and the CRC value, and the error detection mechanism compares the stored CRC with a recalculated CRC to detect corruption.
Solution Approach 2:
The patent introduces a CRC calculator as an intermediary component that computes the CRC of the XOR result and stores it in the XOR buffer. This intermediary mechanism enables comprehensive error detection without requiring additional buffer space beyond what is needed to store the CRC value itself, which is integrated into the buffer structure.
2Reliability
If a parity bit is added to the XOR buffer, then error detection capability is provided, but manufacturing cost increases
Solution Approach 1:
The patent transitions from using a single parity bit to using a CRC parameter set, which provides more robust error detection. The CRC calculator computes multiple bits of redundancy information that can detect a wider range of error patterns, making the system more reliable without requiring a completely different manufacturing approach.
Solution Approach 2:
The XOR buffer is designed to serve multiple functions: storing the XOR result data and storing the CRC value for error detection. This multi-functionality eliminates the need for separate dedicated error detection storage, reducing overall manufacturing cost while maintaining comprehensive error detection capability.
3Reliability
If the XOR buffer is made larger to accommodate error detection mechanisms, then data protection is improved, but device complexity increases
Solution Approach 1:
The patent merges the data storage function and the error detection storage function into a single integrated XOR buffer structure. The CRC value is stored within the same buffer that holds the XOR result, eliminating the need for separate error detection memory modules and reducing overall system complexity.
Solution Approach 2:
The XOR buffer structure is designed to be self-sufficient for error detection by including the CRC calculator and storing the CRC value within the same buffer. This self-service approach eliminates the need for external error detection hardware, simplifying the overall device architecture while maintaining robust data protection.
Data Source
AI summary
An XOR unit is provided in a hard disk controller for calculating an XOR of two operands stored in a buffer memory. The XOR unit includes an XOR calculator for calculating the XOR of the operands and a CRC of the XOR resulting from the calculation. An XOR buffer is also included in the XOR unit for storing the XOR result and the CRC of the XOR result, and a CRC calculator for calculating a CRC of the XOR result stored in the XOR buffer. The CRC calculated by the CRC calculator is compared with the CRC of the XOR result stored in the CRC buffer to determine whether the XOR result has been corrupted in the XOR buffer. The XOR result stored in the XOR buffer is determined to be corrupted if the CRC calculated by the CRC calculator and the CRC stored in the XOR buffer do not match.