Midterm, CM*C 4000, Spring 2024

Name ______________________________________

• The weight for each question is given.
• Use as much paper as you wish, but make your answers are legible.
• Please label your answers with the question number.
• Please answer each question thoughtfully and carefully.
• Please staple this page on top of your answers.
• Answer should reflect the material presented in class.

1. [6 points] What is an operating system? Provide at least two definitions from different perspectives.

2. Kernels
   1. [4 points] What is kernel? (Answer with respect to operating systems.)
   2. [4 points] Name/describe four services provided by a traditional kernel.
   3. [4 points] When does the Linux kernel run? Describe at least two unique/distinct instances.

3. Modern operating systems take advantage multiple modes of operation in a CPU.
   1. [4 points] Name two modes required and discuss the difference between these modes.
   2. [6 points] Why are the two modes needed? Provide an example of a task that should be run in a mode other than user/general. Explain what would happen if this protection were not available.
   3. [2 points] How does the Linux operating system transition into a CPU mode other than user/general mode?

4. Kernel design
   1. [6 points] Compare and contrast micro kernels to monolithic kernels, include a discussion of advantages and disadvantages.
   2. [4 points] How does a module based kernel blend the best of both of the above?

5. System Services
   1. [4 points] What is a loader?
   2. [4 points] Why do different operating systems required different loaders?
   3. [2 points] Where is the Linux loader? (The answer should be a system program or a systems call).