Wear leveling method and device for Nand Flash

Abstract

The invention discloses a wear leveling method and device for Nand Flash, and the method comprises the steps: detecting a writing operation instruction, and obtaining to-be-written target data; judging whether the target data needs to be allocated with a new idle physical block or not; if a new idle physical block needs to be allocated, obtaining the idle physical block with the smallest erasure frequency in the idle queue, writing the target data into the idle physical block, and generating a data physical block; judging whether all the physical blocks meet a preset wear leveling condition ornot; if the preset wear leveling condition is met, migrating the data of the data physical block with the minimum erasure frequency into the idle block with the maximum erasure frequency in the idlequeue to generate a target data block; and repeating the operation until all the physical blocks meet the preset wear leveling condition. According to the embodiment of the invention, the service lifeof the flash memory can be maximized, the influence of data randomness on the service life of the flash memory is solved, and the erasure frequency of each physical block is recorded under the condition of not consuming a large amount of memory resources.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a wear leveling method and device for Nand Flash. Background technique [0002] Nand Flash memory is a kind of flash memory. It adopts nonlinear macro-cell mode inside, which provides a cheap and effective solution for the realization of solid-state large-capacity memory. Nand flash memory has the advantages of large capacity and fast rewriting speed, and is suitable for storing large amounts of data, so it has been more and more widely used in the industry. [0003] Since Nand flash has no rewriting mechanism, after a block is full of data, the data in the block needs to be erased before new data can be written. When the data is updated, rewrite the new data, mark the original data as invalid, and enter the state to be erased. The physical characteristics of solid-state drives determine that their rewritable times are limited. In order to improve the service lif...

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Problems solved by technology

[0007] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a wear leveling method and device for Nand Flash, aiming to solve the problem that the effect of the wear leveling algorithm in the prior art is greatly affected by random factors. I don't know the situation of each block being erased, and at the same time, the randomness request for the logical page cannot be completely equal, so the number of erasures of each block cannot reach an equal probability distribution, and a good wear leveling effect cannot be achieved. technical issues

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