1. COS 598: Advanced Operating System

2. Operating System Review What are the two purposes of an OS? What are the two modes of execution? Why do we have two modes of execution? How does the OS protect the memory space of a user process? How does the OS ensure that a user cannot monopolize the system? What is a process? What is a thread?

3. What is a context switch? Where is process state stored when it is not executing? What information must be stored for a process to be able to resume its execution? What information must be saved in a thread switch? What is an interrupt? What is the interrupt vector? What happens on an interrupt? Provide two circumstances in which an interrupt would be generated? What happens in a system call?

4. What is a race condition? Can a race condition exist in the kernel? What tools are available to avoid race conditions? What is a zombie process? Name two scheduling algorithms? What is your favorite color? What is virtual memory? What is a logical (virtual) address? What is the purpose of a page table?

5. What is a page fault? What happens on a page fault? Is paging good or bad? What is the size of the virtual address space for a 32 bit system? A 64-bit system? Is 2^64 a big number? Assume a system with 8 pages each of which is 1K bytes. How many bits are needed to generate addresses? What is internal fragmentation? What is external fragmentation? What is segmentation? What are two paging algorithms?

6. What is a TLB (Translation Lookaside Buffer)? What is its purpose? Read chapters 1 and 3 in both LKD and ULK. Download Linux kernel.