CSE 120 (UCSD) Principles of Operating Systems True/False Questions

This assignment presents a comprehensive set of 60 True/False questions designed to assess understanding of core Operating Systems concepts. The questions cover a wide range of topics including process management (scheduling, synchronization), memory management (segmentation, pagi...Read More

1. In monitors, it's possible that a condition variable be set to a negative value.
ANSWER-01 (T or F): F
2. When a compiler converts source code to machine code, the memory addresses are physical
addresses.
ANSWER-02 (T or F): T
3. The modified bit can never be 1 if the reference bit is 0.
ANSWER-03 (T or F): F
4. A segment is a fixed size of memory, and all segments are the same size.
ANSWER-04 (T or F): F
5. The I/O buffer cache cannot be implemented as part of the Standard I/O library.
ANSWER-05 (T or F): T
6. If minimizing average turnaround time is important, Multi-level Feedback Queues is preferred over
Round-Robin.

ANSWER-06 (T or F): F
7. In FIFO scheduling, if all processes run for a finite amount of time, starvation is possible.
ANSWER-07 (T or F): F
8. The open system call is typically significantly more time-consuming than the read system call.
ANSWER-08 (T or F): F
9. The purpose of the SETUID mechanism in UNIX is to perform a domain switch.
ANSWER-09 (T or F): T
10. A TLB miss is more time consuming than a page fault.
ANSWER-10 (T or F): F
11. Loading the PC (program counter) register should be the last operation in a context switch.
ANSWER-11 (T or F): T
12. Public Key encryption is more time consuming than Secret Key encryption.

ANSWER-12 (T or F): T
13. Device drivers are part of the device-independent portion of the I/O system.
ANSWER-13 (T or F): T
14. The file system metadata area of a file system contains file names of files.
ANSWER-14 (T or F): T
15. When using a semaphore, a process can learn its integer value.
ANSWER-15 (T or F): T
16. When using a semaphore, a process can learn its integer value.
ANSWER-16 (T or F): T
17. The Two Generals problem shows that one can achieve perfect (100% reliable) communication out
of imperfect (strictly less than 100% reliable) communication channels.
ANSWER-17 (T or F): F

18. Given Public Key encryption, a digital signature can be applied to a document by encrypting the
document with the signer's private key.
ANSWER-18 (T or F): T
19. Locality of reference is a key principle in supporting virtual memory.
ANSWER-19 (T or F): F
20. Message passing relies on processes sharing segments in their virtual address spaces.
ANSWER-20 (T or F): T
21. Storing the return address in an activation record can lead to security problems.
ANSWER-21 (T or F): T
22. Time-sharing relies on processes voluntarily yielding so that each uses one quantum of time.
ANSWER-22 (T or F): T
23. The reason why IPv6 uses 128-bit addresses is because the the Internet was running out of
addresses provided by IPv4.

ANSWER-23 (T or F): T
24. When comparing page replacement algorithms, FIFO is an approximation of LRU.
ANSWER-24 (T or F): T
25. In the CLOCK page replacement algorithm, the reference bit acts like a one-bit time stamp.
ANSWER-25 (T or F): F
26. When the modified bit gets set to 1, the reference bit will also be set to 1.
ANSWER-26 (T or F): F
27. In monitors, a signal operation will always result in unblocking a process.
ANSWER-27 (T or F): T
28. If a single process has two threads, context switching (assuming a single CPU) between them will be
faster if they are kernel-level threads rather than user-level threads.
ANSWER-28 (T or F): T

29. A file system read operation always results in a disk access operation.
ANSWER-29 (T or F): T
30. An access control list describes all the resources that are in a certain domain.
ANSWER-30 (T or F): T
31. In real-time scheduling, if all the deadlines of all the processes can be met by Earliest-Deadline-First,
then they can also be met by Rate Monotonic Scheduling.
ANSWER-31 (T or F): F
32. In segmentation (i.e., a segmented virtual memory), internal fragmentation is a more significant
problem than external fragmentation.
ANSWER-32 (T or F): F
33. The 50%-rule says that if there are n processes, the number that can fit in physical memory is m =
n/2.
ANSWER-33 (T or F): T

34. If a global variable is declared as "static," then it will be located in the stack area of a process's
memory.
ANSWER-34 (T or F): T
35. In the buddy system, there can be no internal fragmentation.
ANSWER-35 (T or F): T
36. Accessing data in a memory-mapped file can be done without the use of read system calls.
ANSWER-36 (T or F): F
37. If a local variable is declared as "static," then it will be located in the data area of a process's
memory.
ANSWER-37 (T or F): F
38. If n users are all running the C compiler program and the operating system supports segmentation,
then only one copy of the compiler's code needs to be stored in physical memory.
ANSWER-38 (T or F): T
39. If two users who have never met each other wish to communicate securely, it is preferable for them
to use Public Key encryption rather than Secret Key encryption.

ANSWER-39 (T or F): F
40. The difference between implementing mutual exclusion using Peterson's solution and semaphores is
that the latter can completely avoid busy-waiting.
ANSWER-40 (T or F): T
41. In the process state diagram, the transition BLOCKED to RUNNING is invalid.
ANSWER-41 (T or F): T
46. If a deadlock occurs, one can use the Banker's Algorithm to recover from it.
ANSWER-46 (T or F): T
51. Porting a C compiler to a different operating system would generally require software modifications
to it (in addition to recompiling it).
ANSWER-51 (T or F): T
52. The memcpy function must be implemented in the kernel.
ANSWER-52 (T or F): F

53. In message passing, the reason for making the send operation synchronous is to increase parallelism.
ANSWER-53 (T or F): F
54. Implementing context switching requires use of the TSL instruction.
ANSWER-54 (T or F): T
55. In the Bully algorithm, if there are processes P1, P2, ..., P100, assuming P37 and P83 never go down
while the others may go down, it is possible that P37 may be the leader, while at other times P83 may
be the leader.
ANSWER-55 (T or F): T
56. In the Red/Black hat problem, if no hint is given BUT at least one person IS wearing a black hat, the
wearers of the hats will NOT be able to determine whether they are wearing a black hat.
ANSWER-56 (T or F): F
57. In LIFO scheduling, if all processes run for a finite amount of time, starvation is possible.
ANSWER-57 (T or F): F

58. With user-level threads, a context switch between threads in the same process need not save and
restore the SP (stack pointer).
ANSWER-58 (T or F): F
59. To increase the maximum number of files that can be supported in a file system, one would increase
the size of the File Metadata area.
ANSWER-59 (T or F): T
60. Semaphores should be global variables rather than shared variables.
ANSWER-60 (T or F): F