Method for forming elastic corresponding of logic area and physic area

Abstract

The invention is a method for forming logic block-physical block elastic corresponding relationship, firstly calculating total number of good and bad physical blocks in flash memory, then allocating according to area number the flash memory has, where each area is provided with fixed number of blocks as register block to make total number of its logic and register blocks in it just equal to that of its physical blocks, and information after allocation is recorded in a good physical block so that at flash memory initialization, a control chip can find the block recording the information and reads the information to store into static random memory in the control chip, and makes a corresponding list of blocks in corresponding areas according to the stored information so as to be able to makelogic and physical blocks in each area correspond in unfixed proportion, i.e. when making bad physical blocks centralized in one or several areas in flash memory, still able to effectively manage internal memory.

Description

technical field [0001] The present invention relates to a management method for flash memory blocks, in particular to a method for making logical blocks and physical blocks form elastic correspondences, so that logical blocks and physical blocks are managed in an unfixed ratio, even if bad physical blocks When the blocks are concentrated in one or several areas in the flash memory, the flash memory can still be effectively managed. Background technique [0002] The evolution of non-volatile memory, from Mask-ROM, OTP ROM, EPROM, EEPROM to flash memory, and flash memory has the traditional advantages of non-volatile memory, and the reading speed is fast, and data can be saved without power consumption, making flash memory It has become a fast-growing product in the semiconductor industry, and related companies use control chips to combine flash memory to make a new storage device such as a flash drive and memory card. Because flash memory has low power consumption, non-volati...

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Problems solved by technology

[0003] However, the current development of high-capacity flash memory has reached a single flash memory with a capacity of 512MB, and its physical block (Block) number is as high as 4096, and due to the static random access memory (SRAM, Static Random Access Memory) on the control chip ) is limited, therefore, the blocks in the flash memory are managed in different regions, and then through the action of swap (swap) to achieve the purpose of the whole region management, and the selection of each region adopts the method of even distribution, for example, with 4096 blocks If the flash memory is divided into four areas, each area will have 1024 blocks. This way of management is quite simple. When the flash memory is evenly distributed with good physical blocks and bad physical blocks, logical blocks and physical blocks Blocks can be in a fixed ratio, but if the bad physical blocks are concentrated in a certain number of areas and not evenly distributed in the flash memory, it will make it impossible to form a fixed ratio between logical blocks and physical blocks Correspondingly, in the process of writing data into this area, there will be no replaceable blocks in this area, and no access to the flash memory will be possible, making the storage device made of this flash memory unusable, making consumer The user must purchase a new storage device, which increases the cost of use

[0004] For a single 512MB flash memory, the total number of physical blocks is 4096, and the total number of logical blocks is 3968. If it is assumed that it is divided into 4 areas, and the total number of bad physical blocks is 80, When the bad physical blocks are evenly distributed in the flash memory, according to the principle that the logical block and the physical block can form a fixed ratio, the number of physical blocks in each area is 1024, and the number of logical blocks is 992. The number of physical blocks is 1004, and the number of redundant temporary storage blocks is 12, so the flash memory can be managed normally, so that the flash memory can be accessed normally; but if the bad physical blocks are concentrated in one or several areas, Then the number of good physical blocks in some areas may be less than 992 logical blocks, resulting in insufficient temporary storage blocks. At this time, there is no way to form a fixed ratio between logical blocks and physical blocks, resulting in Flash cannot be managed properly

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