Semi-Autonomous Memory Modules for SSD Controller Complexity
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Solution Overview
Problem
Existing solid-state drives (SSDs) face challenges with large capacity configurations due to increased complexity in controlling numerous flash memory devices, signal connection burdens, and inflexible block-oriented non-volatile memory allocation, leading to inefficiencies and reliability issues.
Innovation Solution
The implementation of semi-autonomous memory modules with a dedicated module interface and a simplified SSD controller, allowing for point-to-point connections and distributed management functions such as wear leveling, garbage collection, and ECC, reducing the burden on the main controller and enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a controller directly controls a large number of individual flash memory devices in parallel, then storage capacity increases, but device complexity and signal connection requirements increase proportionally
Solution Approach 1:
The system divides the flash storage system into multiple semi-autonomous modules, where each module contains multiple flash memory devices and a dedicated module interface controller. This segmentation allows the main SSD controller to manage modules rather than individual devices, reducing controller complexity while maintaining high storage capacity through parallel module operations.
Solution Approach 2:
Module interface controllers serve as intermediaries between the main SSD controller and the flash memory devices within each module. These intermediaries handle device-level control, signal routing, and management functions, allowing the main controller to operate with fewer direct connections while still managing large numbers of devices through the modular architecture.
2Reliability
If a controller manages all management functions (wear leveling, garbage collection) for numerous memory devices, then comprehensive control is achieved, but interface traffic burden increases
Solution Approach 1:
Management functions such as wear leveling and garbage collection are distributed to individual modules, with each module's controller handling management for its own flash devices. This segmentation of management responsibilities reduces the traffic burden on the main controller interface while maintaining comprehensive memory management through coordinated module-level operations.
Solution Approach 2:
Each module is designed to be semi-autonomous, with its controller capable of independently performing management functions like wear leveling and garbage collection for its own flash memory devices. This self-service capability reduces dependency on the main controller for routine management tasks, thereby reducing interface traffic while ensuring reliable memory management.
3Ease of manufacture
If block-oriented non-volatile memory uses fixed page-size allocation, then simplicity is maintained, but storage efficiency decreases when user data blocks do not match page length
Solution Approach 1:
The system implements dynamic block allocation that allows user data blocks of varying lengths to be efficiently mapped to physical pages. Rather than forcing fixed page-size allocation, the module interface controllers dynamically manage the mapping between variable-length logical blocks and fixed-size physical pages, improving storage efficiency while maintaining allocation simplicity through automated management.
Solution Approach 2:
The system changes the allocation parameter from fixed page-size to variable block-size mapping, where logical block lengths can differ from physical page lengths. The module interface controllers handle the parameter transformation and mapping, allowing efficient utilization of storage space for various data block sizes while maintaining the simplicity of page-based physical memory management.
4Reliability
If the controller directly tests and monitors all memory devices, then system reliability is maintained, but testing and monitoring complexity increases
Solution Approach 1:
Testing and monitoring functions are segmented and distributed to module-level controllers, which independently test and monitor the flash memory devices within their respective modules. This segmentation reduces the complexity of system-wide testing and monitoring while maintaining reliability through comprehensive local oversight, with results aggregated to the main controller.
Solution Approach 2:
Each module performs self-testing and self-monitoring of its own flash memory devices through its dedicated controller, reducing the burden on the main SSD controller. This self-service approach maintains system reliability through continuous local monitoring while simplifying the overall testing and monitoring architecture by distributing these functions across multiple independent module controllers.
Data Source
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AI summary
A memory system for digital data communication with a host device is described to provide data storage capacity. The system can include a controller and a plurality of modules, each module including a nonvolatile memory device wherein the module is configured to perform a management function with respect to the module at least partially based on a parameter. The parameter is provided by the controller and/or the module. The system and modules, in one feature, can support multiple forms of concurrency with respect to data accesses involving the modules.