The Design And Implement Of USB Flash Disk System Based On Android Mobile Terminal

For Android’s disk management, it is ruled that all the applications couldinstalled only in the master storage and the mapping relationship is fixed. Due tosmall internal space, the low-end mobile phones regularly used he extensivestorage(named Secure Digital Card, SD) as the master one to support moreapplications installed which means SD is not allowed to remove or change at randomfor users. Otherwise, the system would not work normally, let alone installing newapplications.To solve the problem above, this paper has proposed and designed a systembased on USB flash drive that switches the master storage dynamically, whichmeans the users could decide who is mapped as the master storage. While SDdevice is installed on the mobile phone, it is mapped as the master storage toensure a large number of different applications installed on low-cost andhigh-capacity mobile phone. On the other hand, once SD device is removed theinternal storage of the mobile phone could be switched to the master oneautomatically to avoid unavailability for new applications installing caused bythe master storage mapping failure.The detailed content in this paper contains as follows:1. The analyst and design of the mechanism that dynamically switching themaster storage. Firstly it analyzes the current reseach status both in domest andoverseas for Android storage space in which indicated the issue the fixedmapping master storage might lead to the applications installing failure. Thencombined with the original design of the disk storage framework for Androidsystem, from the hardware, the driver, the file system and the system management, it designs the mechanism based on USB flash drive that switches the masterstorage dynamically.2. The development and implementation of the dynamic switching technologyincluding system management, file system, driver programming and spacemanagement. It begins with that the internal storage exists in a built-in USBmanner, which means restructuring the partition table of EMMC and increasingthe built-in partition space to connect to PC terminal. Secondly, the node of thekernel USB driver is to be adjusted for improving the ability to access the filesystem of both the built-in USB and SD device. Thirdly, the ability of switchingthe master storage is to be improved. The disk management for Android is torefactor the policy of Vold and Framework, dynamically distributes fstab partitiontable and storage_list file and decide the mapping space of the master storage forusers.3. The validation and testing of the system. This part contains designing the testcases to cover all the functions to verify the success for the proposal. Besides,it takes compatibility testing and performance testing to ensure the program’sstability and robustness.The proposal that switching technology dynamically has been implemented onAndroid4.2and Leadcore L1813platform and tested on the main softwareapplications relying on high capacity storage. The final experiment has proved thatthe design behaved well in the system functions, performance, stability and etc.