What are “caller-saved” and “callee-saved” registers? Where, and when are they saved / restored?
What are the various system calls used for managing processes? Briefly (in one or 2 lines) explain each of them.
What are they 3 main user-space memory regions of a process? What are the 3 main kernel space memory contents of each process?
What is a trapframe? Where does it reside?
Explain the differences between a mode switch and a context switch. When does mode switching occur? When does context switching occur?
What are the hardware features necessary for virtualizing the processor? What are the hardware features necessary for virtualizing memory?
What is the difference between long-term and short-term scheduling?
A process with a run-time of 12 time units that started at time 5 ended at time 36. What are the completion times, turnaround times and wait times for the process?
What are the 3 broad goals of process scheduling policies? Briefly describe the advantages and limitations of a) STCP, b) RR, and c) Ticket based approaches, towards achieving the 3 goals
How does MLFQ achieve short response time? How does it counter the possibility of starvation? How does it differentiate between I/O-bound and CPU-bound jobs?
How can a process game the system if MLFQ is used without anti-gaming measures? How does MLFQ address this?
How does CFS deal with different priorities for different processes?
What are the pros and cons of the 3 main strategies for virtualizing memory? (viz., base-and-bounds, segmentation, and page-tables).
What are the advantages of inverted page tables over multi-level page tables?
What is the purpose of the following bits in PTE entries – “use”, “valid” ,“present” and “dirty”. When, and by what (hardware or software) are these bits set/reset?
When implementing a multilevel paging scheme, what dictates the choice of PTE/PDE size? What dictates the choice of the page size?
Why is the optimal policy for cache management impractical?
Under what condition is the LRU policy a reasonable approximation for the optimal policy?
What makes the LRU impractical?
Briefly explain the clock-algorithm and why it is a practical alternative to LRU.
