NAND Flash Memory Redundant Boot Block Controller
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Solution Overview
Problem
NAND-type flash memory systems face reliability issues due to data damage during reading operations, leading to potential boot failures when data in primary blocks cannot be read, as they lack redundant storage for critical boot programs.
Innovation Solution
Implementing a memory system with dual blocks (BLK0 and BLK1) for storing boot programs, where if data in BLK0 is damaged or unreadable, the system automatically retrieves and transmits the boot program from BLK1, ensuring continuous system operation without requiring explicit read commands from the host apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is stored only in a primary block without redundancy, then the storage structure remains simple, but the system reliability deteriorates due to potential boot failures when primary block data is damaged
Solution Approach 1:
The patent implements a backup block that stores a copy of the boot program data. When the primary block data is damaged or unreadable, the system automatically retrieves the boot program from the backup block, ensuring continuous system operation without requiring explicit read commands from the host apparatus
Solution Approach 2:
The system proactively stores redundant boot program data in a backup block before any data damage occurs. This preliminary redundancy preparation ensures that when primary block data becomes damaged, the system can immediately switch to the backup block without experiencing boot failures, thus cushioning against potential reliability issues
2Reliability
If redundant backup blocks are implemented, then the reliability improves by ensuring boot capability, but the memory device capacity is reduced due to duplicated data storage
Solution Approach 1:
The backup block is specifically dedicated to storing boot program data, while the primary block can store both boot program and general data. This localized redundancy approach ensures that the backup functionality is targeted and efficient, minimizing the impact on overall usable capacity by not requiring complete duplication of all data
3Ease of operation
If the system automatically retrieves data from backup block without host command, then the boot sequence is simplified, but the control complexity increases due to automatic detection and switching logic
Solution Approach 1:
The memory device performs automatic detection of primary block data validity and self-initiated retrieval from the backup block when needed. This self-service mechanism eliminates the need for the host apparatus to implement complex detection and switching logic, simplifying the overall system operation while the memory device handles the complexity internally
Data Source
AI summary
A memory system includes a semiconductor memory device including a plurality of memory blocks, including a first block storing data and a second block storing backup data, a plurality of pins, and a controller configured to output a control signal to the semiconductor memory in accordance with the command. When the controller receives from outside of the memory system, a read command for the data in the first block, and the data in the first block are available, the controller is configured to transmit the data in the first block to the outside of the memory system. When the controller receives from outside of the memory system, a read command for the data in the first block, and the data in the first block are not available, the controller is configured to transmit the backup data in the second block to the outside of the memory system.