Abstract
The major source of mobile weight is batteries, thus reducing the size of battery allows reducing mobile weight, but it will cause also reducing the time of using mobile until it is discharged. On the other hand, by minimizing Mobile power consumption, the batteries size can be reduced because the energy needed will be less. Therefore, it is very important that the operating system use its resources sparingly, to prolong the life of the batteries. This report will explain how operating systems affect power consumption and performance in mobile devices. First, the report will present some arguments about how operating systems play a critical role in mobile design. Second, it will outline some approaches and techniques that operating systems use to reduce power consumption. Finally, it will focus on some mobile OSs, including Windows, Palm, Symbian and Android, how they manage the power and affect mobile performance.