Research And Improvements Of Embedded Linux File System Based On 910GML Platform

With the developing of computing and internet, the text information has not met the demands of users. At the same time, more and more images, animation and video resources appear on the internet. Driven by the schedule of integration telecom, broadcasting and internet works from government, the traditional internet would expand into a comprehensive platform oriented multi-media business that contains images, voice and data applications. Neither the hardware performance nor the software of traditional net terminal would meet the new requirements from users yet. Simultaneously, the challenge raised by huge quantities of information has appeared. The e-boat, which is the one product of 863 subject research from our lab, has not met the requirements from new applications. Also, flash memories, used as the main storage device of e-boat, always are worn out prematurely which has serious effect on the usage of e-boat.Due to the features of low cost, low energy consumption, high integrity, high access speed, high shock resistance and so on, flash memory has become the main storage device of embedded system. However, each physical erase block (PEB) needs be erased before writing data and no more than 100,000 erase cycles are guaranteed for each PEB. In purpose to extending the expected lifetime of the flash memory, it has becomes one of the basic functionality of flash file system that through wear leveling algorithm which would distribute the eraser operations to all blocks averagely to avoid some PEB reaches the max eraser operations prematurely.The work done by the paper could be listed as follow:①Replacing the motherboard of e-boat with the one that contains the Intel 910GML as its core which has made great improvements on the performance of hardware.②Based on the wear leveling subsystem, the paper summaries the results of previous peers and proposes a new wear leveling algorithm which combines the garbage collection and wearing leveling appropriately.③Developing the strategies of temperature evaluation. Based on the schema that is responsible to identify the process (I/O occupation or processor consumption) of Linux kernel, the new strategies ensure that the results are more close to the facts.④By defining over-age (erasure count) area to protect those high-age PEB temporarily, the new algorithm reduces the times of valid data transporting at a large extent. Also, the new algorithm adopts wear leveling strategies that removes protecting measures to new allocated blocks to avoid PEBs'over-load of wear out.The system reaches the using balance among all the PEBs of the flash storage through these measures above. Results of comparative experiments prove that the new algorithm has improved the performance of UBI wear leveling subsystem in PEBs'age standard deviation and system consumption. Transporting the improved system to the 910GML motherboard not only expands the lifetime of flash memories, but also slows down the consumption of embedded system. Enhancing the reliability and durability of e-boat by the methods above, the advantages in software and hardware of embedded system could be raised at some extents, which has improved the practicability and marketability.