Reader Failover for TDMR Magnetic Storage Systems
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Solution Overview
Problem
Magnetic storage systems face challenges in maintaining performance and storage capacity due to increased track density and inter-track noise, where a single reader element failure can lead to loss of entire media surface, especially under varying environmental conditions.
Innovation Solution
A reader failover apparatus and method that employs two reader systems, where the second reader system takes over when the first reader system fails or performs substandardly, ensuring continued data access and improved signal-to-noise ratio by utilizing a buffer to store signals and control circuitry to switch between reader elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If track density is increased to improve storage capacity, then storage capacity is improved, but inter-track noise increases causing reading performance to deteriorate
Solution Approach 1:
The reading function is segmented across multiple independent reader elements (first reader element, second reader element) positioned at different locations. Each reader element reads the same data track independently, allowing the system to process multiple signals and combine them to improve signal-to-noise ratio while maintaining high storage capacity
Solution Approach 2:
Signals from multiple reader elements are merged and combined through signal processing. The control circuitry combines the read signals from the first and second reader elements to produce an enhanced output signal with improved signal-to-noise ratio, effectively reducing the impact of inter-track noise while preserving high storage capacity
2Device complexity
If a single reader element is used to simplify the system, then device complexity is reduced, but reliability deteriorates because failure of one reader element causes loss of entire media surface
Solution Approach 1:
Different reader elements are positioned at different local locations on the head assembly, allowing each to have specialized characteristics optimized for its position. The first reader element and second reader element are located at different radial positions, enabling them to read the same track with different signal characteristics, providing redundancy and improved reliability
Solution Approach 2:
The system is designed with redundant reader elements before any failure occurs. The control circuitry is pre-configured to switch between reader elements and combine their signals, providing a cushion against potential failures. This failover capability ensures that if one reader element fails, the system can continue operating using the remaining reader element(s), preventing loss of media accessibility
3Reliability
If multiple reader elements are used to improve reliability, then reliability is improved, but device complexity increases
Solution Approach 1:
Multiple reader elements serve multiple functions: they simultaneously provide redundant reading capability, enable signal combination for improved signal-to-noise ratio, and offer failover capability. The same reader elements and control circuitry that provide reliability also improve reading performance in high-density environments, reducing the need for separate systems for each function
Solution Approach 2:
The control circuitry automatically manages the complexity of coordinating multiple reader elements through self-service mechanisms. The system automatically switches between reader elements based on signal quality and combines their outputs without requiring external intervention, making the complexity management transparent and reducing the practical burden of the increased system complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that all or most of the magnetic recording media remains readable even when a reader element fails, unlike conventional systems where some media becomes inaccessible, thereby enhancing the robustness and reliability of the data storage system.
Implementation Method 1
magnetic read heads may detect more inter-track noise
Data Source
AI summary
A reader failover system and method are described for a data storage system. At least two reader systems, including a first reader element and a second reader element, situated on the same head, are employed to read a magnetic storage medium. In an aspect, the head is a two-dimensional magnetic recording (TDMR) head. Control circuitry detects when the first reader system provides less than a predetermined performance or fails, and thereafter causes the second reader system, but not the first reader system, to read the magnetic storage medium. In an aspect, a buffer stores a first reader element signal until the control circuitry detects whether or not the first reader element provides less than a predetermined performance or fails. In an aspect, when a reader element fails, data recovery is performed, and all of, or a majority of, the media continues to be readable, improving the data storage system robustness.