Exam

 

1. Describe with the aid of a diagram the structure of the Windows XP operating system. Sketch the functions of each component, and clearly indicate which parts execute in kernel mode and which in user mode.

2. Contrast UNIX pipes with a general, asynchronous message-passing facility as a basis for inter-process communication between processes which run in separate address spaces.

3. An operating system supports multi-threaded processes. Within a given user-level address-space two threads cooperate by means of a shared, circular, N-slot buffer. Semaphores are supported by the language system.

a. Outline programs that may be executed by the thread which writes data into the buffer and the thread which reads data from it.

b. How would you ensure that several threads could write to, and read from, the buffer?

c. Explain how the semaphore implementation in the language system uses the thread implementation in the operating system.

4. Describe the various functions involved in interrupt handling. Indicate the hardware and software that might be involved in their implementation.

a. Discuss the interaction of interrupt driven software and process scheduling in an operating system.

b. Compare and contrast interrupt handling in the Windows XP and UNIX Operating Systems.

5. In relation to scheduling of processes, describe the concept of a working set and briefly outline how it can be used within an operating system.

a. Briefly explain why context switching between processes is inherently more costly than switching between threads of a process.

b. Give two reasons why operating system designers often choose to make code in the kernel non-preemptive.