Flash-Media Controller Direct Write via Translation Cache
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Solution Overview
Problem
Current flash-memory devices face inefficiencies in data transfer due to the need for time-consuming copy operations and resource-intensive lookup tables, especially in small devices with limited storage, which hinders continuous data flow and write speed.
Innovation Solution
A flash-media controller manages non-volatile memory by deferring copy operations and using block descriptors to maintain the state of re-write operations, allowing partial completion of re-write operations without final copy phases and minimizing RAM requirements, thus reducing the need for external storage and lookup tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data is written to flash-memory devices using traditional methods with lookup tables and copy operations, then data can be stored, but write speed is reduced and time is lost due to time costly copy operations and memory intensive look-up tables
Solution Approach 1:
The patent performs preliminary actions by pre-translating logical sector addresses to physical sector addresses and pre-identifying valid blocks before the actual write operation. The flash media controller maintains a translation cache that stores logical-to-physical address mappings in advance, so when a write operation occurs, the data can be directly written to the pre-identified physical location without time-consuming lookups or copy operations during the critical write path.
Solution Approach 2:
The patent extracts and eliminates the time-consuming copy operation from the write path. Instead of copying data through intermediate buffers or performing redundant transfers, the system directly writes data to the target physical sector after address translation. The lookup table functionality is extracted and replaced with a more efficient translation cache mechanism that provides direct address mapping without requiring full sector-by-sector translation.
2Measurement precision
If memory intensive look-up tables are used to associate each logical sector with a physical sector, then address translation is accurate, but storage requirements increase significantly
Solution Approach 1:
The patent applies local quality by making the address translation mechanism adaptive and selective. Rather than maintaining a complete lookup table for all sectors, the system uses a translation cache that stores only the address mappings that are currently needed or recently used. The cache size and structure are optimized based on local access patterns, storing full translations for frequently accessed sectors while using on-demand translation for less frequently accessed sectors.
Solution Approach 2:
The patent changes the parameters of the address translation system from a static, complete lookup table to a dynamic, partial translation cache. The translation cache can be configured with different sizes and replacement policies based on available memory resources. The system transitions from storing all possible address mappings to storing only the necessary subset, with the ability to translate addresses on-demand when not cached.
3Device complexity
If contiguous physical sectors are used to store contiguous logical sectors, then lookup table size is minimized, but the flash-media controller must maintain complex translation tables for damaged blocks and updates
Solution Approach 1:
The patent introduces an intermediary translation cache layer between the logical address space and the physical flash memory. This translation cache handles the complexity of mapping logical sectors to physical sectors, including dealing with damaged blocks and updates. The translation cache absorbs the management complexity, providing a simplified interface to the rest of the system while maintaining the ability to handle bad blocks, wear leveling, and garbage collection transparently.
Data Source
AI summary
In one embodiment, the invention comprises a flash-media controller used for writing new data from an external system to a local flash-memory device. The newly written data may replace old data previously written to the flash-memory device, and may be written directly to unused locations within the flash-memory device. The flash-media controller may comprise a table of block descriptors and sector descriptors used to track specified characteristics of each block and sector of the flash-memory device, thereby allowing for write sequences to non-contiguous sectors within a block. Accordingly, copy operations may be deferred under the expectation that they will eventually become unnecessary, thereby designating old data as having become stale. Once all data within a block has been designated as being stale, the block may be marked as unused and may be made available for subsequent write operations, thereby providing fast write access to the flash-memory device, and significantly reducing the number of required copy operations during data transfer to the flash-memory device.