Flash Memory Data Maintenance via Seed Encoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flash memory devices, such as NAND Flash, suffer from data damage due to repeated access to the same page or block, necessitating a data maintenance method to prevent such damage.
Innovation Solution
A data maintenance method involving a controller that calculates an offset index based on the erase count of a block, retrieves seeds from a random seed table, and encodes data sectors using these seeds to write encoded data sectors into the pages, thereby preventing damage from repeated writes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is repeatedly written to the same page or block in flash memory, then data storage capacity is maintained, but data damage occurs due to wear
Solution Approach 1:
The flash memory is divided into multiple blocks, each block containing multiple pages. The system tracks erase counts at the block level and applies different encoding seeds to different pages within the same block based on their position. This segmentation allows data to be distributed across multiple pages, preventing any single page from being overwritten too frequently and thus extending flash memory lifespan while maintaining data integrity.
Solution Approach 2:
Before writing data to flash memory pages, the system pre-calculates an offset index based on the erase count of the containing block and retrieves appropriate encoding seeds from a random seed table. This preliminary encoding preparation ensures that each page receives uniquely encoded data before the write operation, preventing wear from repeated identical writes and extending the duration of flash memory operation.
2Reliability
If encoding is applied to data sectors using seeds from a random seed table, then page damage is reduced, but device complexity increases
Solution Approach 1:
The random seed table stores multiple pre-generated encoding seeds, and the system selects specific seeds based on the offset index derived from the block's erase count and page position. This local quality approach means that only the necessary encoding operations are performed on specific pages that need protection, rather than encoding all data uniformly. The controller maintains a compact seed table and uses simple index calculations, adding minimal complexity while effectively reducing page damage through targeted encoding.
Data Source
AI summary
A data storage device including a flash memory and a controller. The flash memory includes a plurality of blocks, and each of the blocks has a plurality of pages. The controller receives a write command which is arranged to write a plurality of data sectors into a plurality of first pages of a first block of the blocks, calculates an offset index according to a first erase count of the first block, retrieving a plurality of seeds from a random seed table according to the offset index, encodes the data sectors by using the retrieved seeds to obtain a plurality of encoded data sectors, and writes the encoded data sectors into the first pages.