Research On Boot Mechanism Of Solid State Driver Controller And Wear-leveling Algorithm

With the advent of the intelligent era,the explosive growth of data and the application requirements of different modes have put forward higher requirements on the performance and capacity of storage devices.It is difficult for traditional Hard Disk Drives to meet various low-latency application requirements.Solid-State Drives have gradually become very important storage devices due to their advantages of low power consumption and fast access etc.With the rapid development of semiconductor storage technology,the storage capacity of NAND flash has been rapidly increased,but the endurance has also been reduced,resulting in a shorter lifetime of the Solid-State Drives.The wear leveling algorithm can balance the frequency of use of each block to avoid frequent wear and tear of some blocks into bad blocks,thereby improving the overall lifespan and the write amount of NAND flash.Aiming at the problem of inaccurate selection of moving source blocks during the data writing process of the Solid-State Drives,which leads to invalid moving,this paper improves a wear leveling algorithm(BWWL)for selecting moving source blocks based on block weights.The algorithm uses update frequency,erasure times and effective pages of block as the basis for selecting the moving source block to make the selection of the moving source block more accurate,thereby reducing the cost of moving invalid data.The main work content is as follows:(1)This paper first introduces the knowledge related to SSDs,analyzes the technology involved in the flash translation layer,and the evaluation methods of SSD performance and lifetime.(2)Study the boot mechanism of the SSD controller,and combine the key technologies involved in the boot mechanism to design and test the Boot code.The algorithm code and related algorithm table data of the flash translation layer will be stored in the NAND flash according to the specified rules.After the SSD is powered on,the boot code will first load the relevant code and algorithm table data from the NAND flash to the RAM,and then switch to the flash translation layer code to run.(3)In order to improve the problem of inaccurate selection of moving source blocks in the wear leveling algorithm,the BWWL algorithm is designed.The algorithm synthesizes the three parameters of update frequency,erasure times and effective pages of block to calculate the weight of the block,and identifies the block with the lowest weight as the moving source block.Finally,the effective data of the moving source block is moved to the reclaimed block to achieve block balance.(4)Implement BWWL,PWL and PGWL algorithms on the simulation platform,and compare the performance of different algorithms.Through simulation,compared with other WL algorithms,the BWWL algorithm can obtain a larger amount of writes and prolong the lifetime of the NAND flash under the condition of less triggering wear leveling.