1. When does a computer system switch from user mode to kernel mode? when back to user mod

2. What is a system call? what happens when a system call is made?

3. Does modern operating schedule processes or threads? explain what happens on a context switch for both.

4. What are potential ways an operating system could handle the deadlock problem?

5. What are interrupts, what are traps? How does an operating stem handle interrupts and trap for example, what happens when an interrupt occurs?

6. What is a deadlock? what are the four necessary conditions for the deadlock to occur?

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