LDPC Manufacturing Test Iterations for Storage Media Error Screening
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Solution Overview
Problem
Current methods for testing 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 manufacturing defects are below acceptable levels, particularly in balancing error rate reduction with processing resources and test time.
Innovation Solution
A manufacturing test system that uses LDPC codes to encode data written to storage media, performs iterative decoding to determine an error rate function, and sets a passing error rate based on this function, allowing for optimized test iterations and time allocation to ensure media quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If iterative decoding is performed to determine error rate function, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent performs preliminary actions by generating an error rate function through iterative decoding during manufacturing testing before product deployment. This preliminary characterization of error rates under various conditions allows the system to establish baseline performance metrics and confidence levels in advance, eliminating the need for extensive iterative decoding during operational testing.
Solution Approach 2:
The patent applies partial action by performing a limited number of iterative decoding operations (e.g., 3 iterations) during manufacturing testing to generate the error rate function, rather than performing exhaustive iterative decoding. This partial action is sufficient to capture the essential error rate characteristics while significantly reducing test time compared to complete iterative decoding.
2Reliability
If number of test iterations is increased to reduce error rate, then reliability is improved, but productivity decreases
Solution Approach 1:
The patent performs a limited number of test iterations (partial action) to generate the error rate function during manufacturing testing. By performing only 3 iterations rather than exhaustive decoding, the system achieves sufficient reliability assessment to distinguish functional from non-functional media while maintaining high test throughput and productivity.
Solution Approach 2:
The error rate function is generated as a preliminary action during manufacturing testing, establishing reliability metrics in advance. This preliminary reliability characterization allows the system to make confident pass/fail decisions without requiring additional iterative decoding, thus maintaining high productivity while ensuring reliability.
3Reliability
If manufacturing testing is performed to ensure defect levels, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent performs a limited number of writing and reading operations (partial action) during manufacturing testing to generate the error rate function. By performing only 3 iterations of encode-write-read operations, the system achieves sufficient defect detection capability to identify non-functional media while significantly reducing testing duration compared to exhaustive testing methods.
Solution Approach 2:
The error rate function generation is performed as a preliminary action during manufacturing testing, establishing defect detection capabilities in advance. This preliminary testing approach allows the system to identify non-functional media with high confidence while minimizing testing time, as the error rate function captures the essential reliability characteristics.
Data Source
AI summary
A technique for tested is disclosed herein. A low-density parity-check (LDPC) code is received. For the received LDPC code, an error rate function is generated that is a function of a number of iterations. A number of test iterations and a passing error rate are determined using the error rate function. One or more storage media are tested using the LDPC code, the number of test iterations, and the passing error rate.