Flash Memory Controller Suspension Handling
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Solution Overview
Problem
Existing recording devices using NAND flash memory face challenges in achieving high-speed real-time recording and efficient area use due to the need for entrainment saving processing, which slows down data recording when writing in smaller units than physical block size, leading to potential stopping of real-time recording and inefficient use of storage space.
Innovation Solution
A recording system comprising a recording device and an access device that manages nonvolatile memory by dividing it into predetermined block length units, allowing for unrecorded blocks to be identified and used for data recording, and includes a memory controller that stores suspension information when recording is paused, enabling high-speed recording and efficient area use by avoiding unnecessary data copying during suspension and resumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If entrainment saving processing is performed to copy valid data when writing in smaller units than physical block size, then data integrity is maintained, but recording speed decreases
Solution Approach 1:
The system performs preliminary actions by pre-allocating entire physical blocks for logical units and maintaining a mapping table that tracks which logical units correspond to which physical blocks. This preliminary organization eliminates the need for entrainment saving processing during normal write operations, as data can be directly written to the designated physical block without copying existing valid data.
Solution Approach 2:
The patent uses a mapping table as a copy of the logical-to-physical address relationship. This mapping structure allows the system to track valid data locations without physically copying data between blocks during write operations, thereby maintaining data integrity while avoiding the speed penalty of entrainment saving processing.
2Quantity of substance
If fixed-length blocks are used for data storage management, then area use efficiency improves, but recording speed decreases due to overhead of entrainment saving processing
Solution Approach 1:
The patent segments the storage hierarchy into logical units (smallest addressable unit), logical blocks (collection of logical units), and physical blocks (erasure unit). This segmentation allows the system to manage data at different granularities: logical units for efficient addressing, logical blocks for flexible allocation, and physical blocks for NAND flash erasure operations. The mapping table bridges these segments, enabling efficient area utilization without requiring entrainment saving processing.
Solution Approach 2:
The system performs preliminary block allocation and maintains a mapping table that pre-establishes the relationship between logical and physical blocks. This preliminary action eliminates the need for runtime data copying during write operations, allowing the system to achieve both high area efficiency and recording speed by directly writing to pre-allocated physical blocks.
3Productivity
If real-time recording is performed at high speed, then recording continuity is maintained, but area use efficiency decreases due to need for frequent entrainment saving processing
Solution Approach 1:
The system performs preliminary allocation of physical blocks for logical units and maintains a mapping table that tracks valid data locations. This preliminary organization allows real-time recording to proceed at high speed without interrupting entrainment saving processing, as data can be directly written to the mapped physical blocks. The mapping table enables efficient area utilization by tracking which physical blocks contain valid data, avoiding wasted space while maintaining recording continuity.
4Adaptability or versatility
If data is written in smaller units than physical block size, then flexibility in data management is improved, but recording speed decreases due to necessary data copying
Solution Approach 1:
The patent implements a three-level segmentation: logical units (smallest addressable unit with 512-byte granularity), logical blocks (collection of logical units), and physical blocks (NAND flash erasure unit). This segmentation enables flexible data management at the logical unit level while avoiding speed penalties by using a mapping table to directly locate the corresponding physical block for each write operation, eliminating the need for data copying between blocks.
Solution Approach 2:
The mapping table serves as an intermediary structure that bridges logical units and physical blocks. It stores the correspondence relationships without requiring physical data movement. When data needs to be written to a logical unit, the mapping table quickly identifies the target physical block, enabling flexible data management at the logical level while maintaining high recording speed by avoiding intermediate data copying operations.
Data Source
AI summary
A recording device operates in accordance with an instruction from an access device. The recording device comprising a nonvolatile memory that stores data, a communication unit that receives an instruction issued by the access device, and a memory controller that controls the nonvolatile memory. When a recording instruction for recording data into the nonvolatile memory is received from the access device, the memory controller starts recording of data into the nonvolatile memory. When the memory controller receives from the access device a suspension instruction for suspending the recording of data, the memory controller stores suspension information into the nonvolatile memory, the suspension information indicating a suspended position as a position in a recording area of the nonvolatile memory at which the data is being recorded upon reception of the suspension instruction.