SSD Media Controller Summary Page Cache for Translation Data
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Solution Overview
Problem
Current flash memory storage devices face inefficiencies in storing logical-to-physical translation data for solid state disks (SSDs), particularly in managing random access, write performance, and memory utilization due to limitations in existing logical-to-physical translation table management techniques such as direct page mapping, block mapping, and superblock mapping, which lead to excessive RAM usage, inefficient data access, and reduced flash memory capacity.
Innovation Solution
A media controller for SSDs that stores logical-to-physical address translation data in summary pages, utilizing a buffer layer module to manage a summary page cache and perform operations efficiently, allowing for sequential and random data transfers with limited RAM, and includes features like wear leveling and garbage collection to extend flash memory life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If direct page mapping is used to store logical-to-physical translation data, then random access performance is improved, but RAM usage increases excessively
Solution Approach 1:
The translation data is segmented into summary pages that map logical blocks to physical blocks, rather than storing complete page-by-page mappings. This segmentation reduces the amount of translation data that must be stored in RAM while maintaining efficient access patterns.
Solution Approach 2:
A summary page cache is introduced as an intermediary structure between the logical address space and physical address space. The summary pages store block-level mappings and are cached in RAM to facilitate quick translation lookups without requiring full page mapping tables.
2Quantity of substance
If block mapping is used to reduce RAM usage, then write performance degrades due to sequential write requirements
Solution Approach 1:
The mapping structure is segmented at the block level rather than page level, allowing the system to maintain fewer entries in RAM while still supporting efficient writes. The summary pages are updated atomically during writes, enabling both low RAM usage and good write performance.
Solution Approach 2:
The system performs preliminary actions by pre-allocating and pre-mapping blocks before actual data writes occur. This allows the translation table to be prepared in advance, enabling faster writes without requiring extensive RAM for detailed page-level mappings.
3Productivity
If superblock mapping is used to manage translation data, then data access efficiency improves, but flash memory capacity is reduced
Solution Approach 1:
The flash memory is segmented into superblocks with associated summary pages that store translation metadata. This segmentation allows efficient data access through the summary page cache while preserving the bulk of flash memory capacity for actual data storage, as only the essential block-level mapping information is stored in the summary pages.
Data Source
AI summary
Described embodiments provide a media controller for a storage device having sectors, the sectors organized into blocks and superblocks. The media controller stores, on the storage device, logical-to-physical address translation data in N summary pages, where N corresponds to the number of superblocks of the storage device. A buffer layer module of the media controller initializes a summary page cache in a buffer. The summary page cache has space for M summary page entries, where M is less than or equal to N. For operations that access a summary page, the media controller searches the summary page cache for the summary page. If the summary page is stored in the summary page cache, the buffer layer module retrieves the summary page from the summary page cache. Otherwise, the buffer layer module retrieves the summary page from the storage device and stores the retrieved summary page to the summary page cache.