LDPC Manufacturing Test Iteration Selection for Storage Media
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Solution Overview
Problem
Current methods for manufacturing testing of low-density parity-check (LDPC) codes in storage media, such as hard disk drives and Flash drives, face challenges in efficiently determining error rates and ensuring defect levels, particularly in balancing error rate reduction with processing resources and test time.
Innovation Solution
A manufacturing test system and process that uses LDPC codes to encode data written to storage media, with an error rate function generated to determine the number of test iterations and a passing error rate, allowing for effective testing and defect detection while optimizing test time and resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of test iterations is increased to reduce error rates, then reliability is improved, but test time increases
Solution Approach 1:
The patent applies partial action by performing a limited number of test iterations (e.g., 3 iterations) rather than exhaustive testing. This partial approach achieves sufficient error rate reduction for manufacturing decisions without incurring the full time cost of maximum iterations, resolving the contradiction between reliability and test time.
Solution Approach 2:
The patent changes the parameter of iteration count from a fixed maximum value to a variable parameter that can be optimized. By determining an optimal number of iterations based on error rate functions and manufacturing requirements, the system achieves the desired reliability threshold with minimal test time, balancing both contradictory requirements.
2Measurement precision
If the number of test iterations is increased to improve error rate detection, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent performs only the necessary number of iterations (partial action) to achieve sufficient error rate detection precision for manufacturing decisions. This avoids the productivity loss that would result from performing maximum or excessive iterations, maintaining high testing throughput while achieving adequate measurement precision.
Solution Approach 2:
The patent performs preliminary analysis to determine the optimal number of iterations needed before conducting the actual manufacturing tests. This preliminary determination of iteration count ensures that subsequent testing achieves the required precision without unnecessary iterations, thereby maintaining high productivity.
3Reliability
If manufacturing testing is performed with sufficient iterations to ensure quality standards, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent transforms the iteration count from a fixed parameter to an optimized parameter determined by error rate functions. This allows the system to achieve quality standard compliance with the minimum necessary iterations, reducing manufacturing test time while maintaining reliability.
Solution Approach 2:
The patent applies partial action by performing only the sufficient number of iterations needed to meet quality standards rather than performing maximum iterations. This partial approach ensures quality compliance while minimizing the time loss in manufacturing testing.
Data Source
AI summary
An amount of time and an error rate function are received, where the error rate function defines a relationship between a number of iterations associated with iterative decoding and an error rate. A testing error rate is determined based at least in part on the amount of time. The number of iterations which corresponds to the testing error rate in the error rate function is selected to be a testing number of iterations; the testing error rate and the testing number of iterations are associated with testing storage media using iterative decoding.