| Summary: | 碩士 === 國立中正大學 === 通訊工程研究所 === 96 === Compare to traditional hard disks, flash memories have become storage medias on embedded device because of shock resistant and energy efficiency. For example, SD card, MMC, MemoryStickTM, CompactFlashTM and SmartMediaTM are products of flash memory.
In the flash memory management, because of the limitation of a certain number of erase operation on a block and a high locality on Garbage Collection caused by the locality (temporal & spatial) of write operation on operating system, traditional mechanisms try to reduce the locality on Garbage Collection, extending the life-time of the flash memory.
In this paper, we propose four mechanisms: Enhanced Ice-CAP algorithm, H/C Region Manager, Fast Boot and Compression. In Enhanced Ice-CAP algorithm, we use the locality on operating system to extend the life-time of flash memory. In H/C Region Manager, we use hash table to classify the user data and increase the locality on Garbage Collection. In Fast Boot, we use the result of data classification to save a part of FTL to decrease the boot-up time. Since MLC flash memories no longer support partial programming, the spare area in every page can only be written once. Therefore, the block information like “erase count” must be saved to another place or it’ll conflict the hardware property of MLC flash memory. Since the data are too large, we use Compression to reduce the utilization of flash memory space.
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