Storage Controller Map Data Segmentation for Read Speed
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Solution Overview
Problem
Current storage devices face challenges in improving operating speed as the capacity of nonvolatile memory increases, due to limitations in managing map data and converting logical addresses to physical addresses efficiently.
Innovation Solution
A storage device with a controller that uses cache map data and partial map data stored in internal RAM to optimize address conversions, distinguishing between sequential and random data, and managing these data types using a set associative cache algorithm to reduce reliance on nonvolatile memory reads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If map data is stored entirely in nonvolatile memory, then data persistence is ensured, but read speed decreases due to frequent accesses
Solution Approach 1:
The patent segments map data into two categories: cache map data (for sequential data) and partial map data (for random data). Cache map data is stored in internal RAM for fast access, while partial map data remains in nonvolatile memory. This segmentation allows the system to optimize read speed for sequential operations while maintaining data persistence for random access operations.
Solution Approach 2:
The patent introduces internal RAM as an intermediary storage layer between the host device and nonvolatile memory. The controller uses this intermediary to store cache map data, reducing direct accesses to nonvolatile memory and thereby improving read speed while maintaining data persistence through the controller's management of the intermediary layer.
2Speed
If all map data is converted and stored in internal RAM, then read speed improves, but device complexity and memory usage increase
Solution Approach 1:
The patent applies local quality by treating different types of map data differently based on their access patterns. Cache map data (sequential) is stored in internal RAM with simple management, while partial map data (random) remains in nonvolatile memory with more complex management only where necessary. This localized differentiation improves read speed for sequential operations without uniformly increasing device complexity across all memory management operations.
Solution Approach 2:
The patent implements partial action by converting only the necessary portion of map data (cache map data for sequential operations) to internal RAM, rather than converting all map data. This selective conversion improves read speed for sequential operations while avoiding the unnecessary complexity and memory usage that would result from converting excessive data.
3Speed
If cache map data is used for sequential data, then read speed improves, but write operation complexity increases
Solution Approach 1:
The patent introduces dynamic management of cache map data validity through cache tags. The controller dynamically updates cache tags to reflect whether cache map data is valid or needs updating. This dynamic approach allows the system to maintain simple cache operations for sequential reads while automatically handling write operation complexity through validity tracking, rather than requiring complex predetermined write management protocols.
Solution Approach 2:
The patent implements feedback mechanisms through cache tags that provide information about the validity of cache map data. This feedback allows the controller to make informed decisions about whether to use cache map data for address conversion or to retrieve updated map data from nonvolatile memory, thereby managing write operation complexity through automated feedback-driven validation rather than complex manual management.
4Measurement precision
If logical to physical address conversion is performed for every read request, then address accuracy is maintained, but processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-converting logical addresses to physical addresses for sequential data and storing them as cache map data in internal RAM. This preliminary conversion eliminates the need to perform address conversion for every read request of sequential data, thereby maintaining address conversion accuracy through proper cache management while significantly reducing processing time for sequential operations.
Solution Approach 2:
The patent uses copying by creating cache map data as a copy of the address conversion information from map data. This copy is stored in internal RAM for rapid access during read operations. The copying mechanism maintains address conversion accuracy by ensuring the cache copy is properly validated and updated, while reducing processing time by avoiding repeated full address conversion operations.
Data Source
AI summary
A storage device including a nonvolatile memory device is provided. The storage device may include: a nonvolatile memory device; and a controller configured to control a read operation of the nonvolatile memory device according to a read request from an external host device. The controller is configured to read map data including a segment, and to store different types of map data in an internal random access memory (RAM) based on determining whether the segment corresponds to sequential data.