sumamry operating system, Summaries of Computer Science

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MULTIPLE CHOICE QUESTIONS

1. What is not a drawback of contiguous allocation a. Compaction (answer)

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1. What is true about deadlock? a. You need mutual exclusion, no preemption, circular wait and (4th condition for deadlock) to imply deadlock (answer)
2. What is true about swap maps a. Kernel to track swap space use (answer)
3. Given a thrashing graph, you're given arrays of [pages, frames]. For each of these, what's the appropriate response? a. Allocate more frames b. Take away frames c. Do nothing, d. End process
4. For each resource allocation graph, is it: (shows 4 graphs) a. Safe b. Safe but potential deadlock c. Deadlock d. Unsafe
5. What’s an advantage for linked allocation? a. Ease of implementation (answer)
6. What is true about the resource allocation graph? a. Graph with a cycle and one instance implies deadlock (answer)
7. What is true about physical addresses? a. Specifies a physical location in memory (answer)
8. What is not a method for handling deadlocks? a. Delaying deadlocks (answer)
9. What is not true about demand paging? a. Brings page into memory when nearby reference is made (answer)
10. What is true about the OS Kernel? a. Usually held in low with interrupt vector (answer)
11. What is true about RAID? a. Reliability achieved via mirroring (answer)

1. Using Dynamic Allocation, choose that allocates maximum space…… forgot question a. Best fit (answer) b. Worst fit c. Next fit d. First fit SHORT ANSWER
2. Given a diagram of Frames/Pages, Free Frame List, Modified Page List, then you're given a sequence of WRITES/READS on pages: what's the state of frames/pages/lists after each reference (had no idea how to do this, this question is about page buffering)
3. LRU/FIFO/OPT/CLOCK (the reference queue used was the same for all algorithms: 6 3 1 5 3 4 3 2 5 4 3 4 5 1 5 3 1 6 3 1 (split into 4 questions, one for each alg.) a. state after 3rd ref? b. 10th ref? c. 15th ref? d. last ref? e. how many page faults
4. Question about disk scheduling, had to apply 4 algorithms (SSTF/SCAN/C-LOOK/C-SCAN), start at 46(served), 176,115,117,58,60,7,31,91 (split into 4 questions, one for each alg.) a. For SSTF what was 6 reference b. For SCAN what was 4th c. For C-LOOK what was 7th d. For C-SCAN what was 4th LONG ANSWER
5. Doing address translation for segmentation - Basic conversion of logical to physical addresses
6. Bankers algorithm question, very basic (for this question there were a bunch of answers on the side and we just had to match it to the question) a. Part 1, find need matrix for initial state b. Part 2, asks if initial state is safe (do safety algo) c. Part3, if P1 makes request (1,1,0,1) what happens d. Part4, if P3 makes request (1,0,0,0) what happens The image if for bankers algorithm Q, they only gave allocation, max matrix and available vector