Explain the two main functions of an Operating System. [2Marks] 2. Which of the following statements is TRUE about CPU scheduling? [5Marks] Select one or more options: A. A scheduling algorithm for processes is preemptive if a process can be forced to give up access to the CPU. B. Time-sharing systems generally use a preemptive CPU scheduler. C. Response time is more predictable in preemptive systems than in non-interruptible systems. D. CPU scheduling is not required in multi-user systems. E. Scheduling in popular operating systems such as Linux and Windows gives the same priority to all processes. F. For jobs that require a lot of processing, short time periods ("time slices") are most effective. G. Compared to FIFO, Round-Robin is better for interactive jobs. H. By using a priority scheduler, all processes will always have an equal share of time on the CPU. I. The CPU scheduler must run / execute when a process terminates. 3. Could adding more memory to a computer make it run faster? [2Marks] 4. Explain the difference between mode switch and context switch? [2Marks] 5. An application is to be coded using threads. Describe condition under which you would recommend use of (a) kernel-level threads, (b) user-level threads [2Marks] 6. What are the differences between deadlock, livelock, and starvation? [2marks] 7. A machine has 48-bit virtual addresses and 32-bit physical addresses. Pages are 8 KB. How many entries are needed for a single-level linear page table? [2Marks]

8. The readers and writers problem can be formulated in several ways with regard to which category of processes can be started when. Carefully describe three different variations of the problem, each one favouring (or not favouring) some category of processes. For each variation, specify what happens when a reader or a writer becomes ready to access the database, and what happens when a process is finished. [3Marks]

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