Research On Storage Management Algorithm For Flash Memory

Because Flash memory has the advantages of small size, light weight, low-cost, high-integration, anti-vibration, it is widely used in MP3, MP4, mobile phones and other mobile devices. Best practices in the Flash memory used in embedded systems are in Flash memory to construct a file system, applying the file code in Flash memory when storing and managing the file. Flash memory cannot be unlimited erased, namely it has a limited life. The maximum range of the erasing time each memory block is generally in the range of105to106times. Therefore in the file storage process a special mechanism must be applied to balance each memory block avoiding certain blocks in advance to damage, finally affecting the entire Flash memory.Continuous space and equal probability store algorithm defines the same writing time and continuous memory block as continuous space, which leads to find that the continuous space is not great, thus affecting the speed of finding and reading the file. In fact in the huge file storage process, the system is not sensitive to the certain fluctuation range writing times and continuous memory block. The first algorithm is proposed in this article. The main idea is to join a dynamic range on the basis of continuous space and equal probability store algorithm, in order to expand the continuous space, making the files stored greater continuous space in file storage process, further solving the problem of uneven use of storage space.In the algorithm simulation result, the space utilization is increased by several times after adding the dynamic range. At the same time, this algorithm only focuses on the constantly erasing files. In fact in the file storage process, not only the constantly erasing files are included, but also the not erasing files stored in the memory block for a long time are included, which led to a part of flash memory is made full use of, the other part is not used. As a whole that results in flash memory storage space is not balanced use. In order to solve the problem of uneven utilization of flash memory storage space, Based on static data load balancing store algorithm is also proposed in the paper. The not erasing files for a long time are moved the memory block of the often erasing and the large writing times to ensure that the degree of utilization of the flash memory storage space is maximized, optimize the overall storage performance and prolong the life of flash memory.The two algorithms are designed in the paper on the basis of continuous space and equal probability store file management system, and are simulated through the C++program. The experimental results are shown that in the same condition continuous space and equal probability store algorithm defines the same writing time and continuous memory block as continuous space. The first algorithm is proposed-although dynamic and continuous space and equal probability store algorithm in terms of the total writing times is slightly inferior to continuous space and equal probability store algorithm, in the average disconnected number of the files is significantly less than continuous space and equal probability store algorithm, improve the continuity of the files and reduce the time of finding and reading the files. The second algorithm is proposed-based on static data load balancing store algorithm. The unmoved files for a long time are moved to memory block of the higher writing times in order to avoid that a part of flash memory is not made full use of due to storing the unmoved files for a long time, the other part reach the damage in advance due to the constantly erasing. Finally extend the life of Flash memory.