1. Define multiprogramming.

2. In the following picture of a multiprogrammed, multi-user computer system where are the controllers?

3. In the same picture, in which memory region would the OS code usually be put?

4. What is another name for controller?

5. When a device (the main CPU or a controller) wants to access main memory, it must temporarily control it. What do we call the role that this device temporarily takes on?

6. The huge disparity in speeds of which devices in a computer systems makes multiprogramming feasible?

7. Fill in the following table:

              To read from a ...                 It takes _____ nanoseconds
              ------------------                 --------------------------
                 register
                 main memory cell
                 hard disk sector

8. Explain how an interrupt can be used to coordinate the activities of an I/O controller and the main CPU.

9. What happens if several user jobs finish and collectively there is enough memory to start a new job, but it is broken into several noncontiguous pieces?