28 May '15, 3pm
Using an MMU:
A common use of an MMU is to implement an operating system using process model – like Linux. In this case, each task has one or more dedicated areas of memory for its code and data. When a task is made current by the scheduler, the MMU maps these physical addresses onto a logical address area starting from 0. All the physical memory belonging to other tasks (processes) and to the OS itself is hidden from view and, thus, protected. Each process behaves as if it has free use of the entire CPU. Although this mechanism is safe and elegant, it has the drawback that there is an overhead – the MMU remapping – on every context switch.