Read Channel Memory Selective Access for Disk Controller
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Solution Overview
Problem
Conventional hard disk drives (HDDs) face increased costs and complexity due to the growing need for larger read channel memory to support higher storage densities, as the memory required for error correction processes increases with storage density, limiting performance and efficiency.
Innovation Solution
The HDDs are designed to allow selective access to the read channel memory by the disk controller during non-read operations, enabling memory transfers to utilize the read channel memory and reducing the overall memory requirements by sharing resources between the read channel and disk controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the storage capacity of HDD is increased by shrinking track dimensions, then more tracks can be fitted onto each storage disk, but inter-track interference becomes an important performance issue and read channel memory requirements increase
Solution Approach 1:
The read channel memory is made accessible to multiple components (read channel circuitry and disk controller) for different functions. The disk controller can access the read channel memory for memory transfers during non-read operations, allowing the same memory resource to serve both error correction and data transfer purposes, thereby reducing overall memory requirements in the system
Solution Approach 2:
The memory access permissions are made dynamic rather than static. The read channel memory is selectively accessible to the disk controller based on the operational state of the read channel circuitry. When the read channel is not performing read operations, the disk controller is permitted to access the memory, creating a dynamic sharing arrangement that adapts to system needs
2Reliability
If the read channel memory size is increased to support higher storage densities, then error correction processing can be maintained, but the cost and complexity of the HDD significantly increase
Solution Approach 1:
The read channel memory serves dual purposes: it maintains error correction capability for the read channel while also being accessible to the disk controller for memory transfers. This multi-functional use allows the system to maintain reliability for error correction without proportionally increasing overall system complexity and cost
Solution Approach 2:
The system recovers unused memory capacity by allowing the disk controller to utilize the read channel memory during non-read operations. When the read channel is idle, the memory capacity that would otherwise be idle is recovered and put to productive use for disk controller memory transfers, effectively increasing system efficiency without additional hardware
3Reliability
If the read channel memory is exclusively used by the read channel for error correction, then error correction processing is ensured, but the disk controller requires separate memory resources increasing overall memory requirements
Solution Approach 1:
The read channel memory is designed to be universally accessible to both the read channel circuitry and the disk controller. This allows the same memory resource to be shared for different functions: error correction when the read channel is active, and memory transfers when the disk controller needs access, thereby reducing the total memory required in the system
Solution Approach 2:
The patent merges the read channel memory with the disk controller memory space by allowing the disk controller to access the read channel memory as if it were part of its own address space. This consolidation eliminates the need for separate memory resources for both components, reducing overall memory requirements while maintaining both error correction and data transfer capabilities
Data Source
AI summary
A hard disk drive or other disk-based storage device comprises a storage disk, a read/write head configured to read data from and write data to the storage disk, and control circuitry coupled to the read/write head and configured to process data received from and supplied to the read/write head and to control positioning of the read/write head relative to the storage disk. The control circuitry comprises a disk controller and read channel circuitry, with the read channel circuitry comprising a read channel memory. The control circuitry is further configured to selectively permit the disk controller to access the read channel memory. For example, the disk controller may be permitted to access the read channel memory only when the read channel circuitry is not performing a read operation.