Research And Implemention Of Fast Boot Technique Based On Android Platform

With completely features of free and open source, Android is sweeping the mobileterminal market. According to the latest figures, Android dominates the globalintelligent mobile phone operating system market share of more than70%. In the nearfuture, Android may also be applied to the medical, industrial control, environmentalprotection, transportation and other more complex domain.With the popularity of Android system, the optimization of Android system hasattracted many domestic and foreign researchers and manufacturers. Android is an opensource operating system, with universal and huge framework design, however, makesthe booting speed slow. We improve the boot speed to achieve a good user experience,and provide different fast-booting solutions to meet the needs of different users.Two sorts of fast-booting techniques are presented in this dissertation，one issuspend-based fast-booting technique, and the other is hibernation-based fast-bootingtechnique. Both techniques have the same basic principles, by restoring the machine to aknown running state from saved system state. The dissertation firstly introducesAndroid architecture, power management, the normal boot-up procedure of Android;Secondly, the dissertation introduces the basic principles and the design architecture;Then, the dissertation introduces the experimental platform, debugging techniques,analyzes the procedure of fast-booting technique; Finally, we evaluate the performanceof our implementation.The suspend-based fast-booting technique saves the system state to RAM, so thetime of restoring system to working state is very short, only0.127seconds; whilehibernation-based fast-booting technique saves the system state in external non-volatilestorage, the system state is copied to RAM firstly at startup, and then restores thesystem to working state. The whole process takes about10seconds, accounting for24%of Android startup time.We also optimize hibernation-based fast-booting techniqueusing several other techniques: shrinking the hibernation image technique makesreading the hibernation image time reduced by63.19%, compressing the hibernationimage technique makes saving the hibernation image time reduced by23.81%, the way of the hibernation image coped by uboot makes the start-up time reduced by41.12%,achieving the start-up time about5seconds. Therefore, these Android fast-bootingtechniques can effectively achieve the fast boot, and different fast-booting solutions canmeet the needs of different users.