Paper 2 CS · UNIT 05 · MOCK TEST

System Software and Operating System — Mock Test 7

25 questions · about 30 minutes. Press End Mock any time to see your score and the correct answers.

0 / 25 answered 00:00

Q1. Which of the following statements are CORRECT?
(A) A process always checks the state of the currently executing process to enter the critical section.
(B) Spin locks use busy waiting.
(C) Periodically testing a variable until some value appears is known as busy waiting.
(D) A critical region is the part of the program where shared memory is accessed.
(E) The printer daemon continuously checks to see if there are any files to be printed.
Choose the correct answer from the options given below:

A(A) and (B) Only B(B) and (C) Only C(B) and (D) Only D(B) and (E) Only

Q2. Match List I with List II

List I	List II
(a) LRU	(I) A page is written to secondary memory only when it has been selected for replacement
(b) Demand cleaning	(II) A page that has not been referenced for the longest time is replaced
(c) Long-term scheduling	(III) The decision to add to the number of processes that are partially or fully in main memory
(d) Medium-term scheduling	(IV) The decision to add to the pool of processes to be executed

A(a)-(I), (b)-(III), (c)-(IV), (d)-(II) B(a)-(II), (b)-(I), (c)-(IV), (d)-(III) C(a)-(III), (b)-(II), (c)-(I), (d)-(IV) D(a)-(IV), (b)-(II), (c)-(III), (d)-(I)

Q3. Arrange the following levels of interrupt protection within the Linux kernel in order of increasing priority.
(a) User-mode programs
(b) Bottom-half interrupt handlers
(c) Kernel system service routines
(d) Top-half interrupt handlers
Choose the correct answer from the options given below:

A(a), (b), (d), (c) B(a), (c), (b), (d) C(a), (c), (d), (b) D(d), (a), (c), (b)

Q4. Statement (I): A thread is a dispatchable unit of work that does not execute sequentially and is not interruptible.
Statement (II): It is not possible to alter the behaviour of a thread by altering its context when the thread is suspended.
In the light of the above statements, choose the most appropriate answer from the options given below:

ABoth Statement I and Statement II are correct BBoth Statement I and Statement II are incorrect CStatement I is correct but Statement II is incorrect DStatement I is incorrect but Statement II is correct

Q5. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: I/O protection is ensured by a hardware trap.
Reason R: I/O interrupts are caused by conditions like I/O completion and device malfunction occurring within the I/O devices.

ABoth A and R are true and R is the correct explanation of A BBoth A and R are true but R is NOT the correct explanation of A CA is true but R is false DA is false but R is true

Q6. Consider the following statements:
S1: The LRU page-replacement algorithm suffers from Belady's anomaly.
S2: Shortest-remaining-time-first scheduling may cause starvation.
S3: The stack is shared by all threads in a process.

AS1, S2 and S3 are true BS1, S3 are false and S2 is true CS1, S2 are false and S3 is true DS1, S2 and S3 are false

Q7. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: A process invokes a library function to create a thread.
Reason R: Threads make system calls to convey their resource and I/O requirements to the kernel.

ABoth A and R are true and R is the correct explanation of A BBoth A and R are true but R is NOT the correct explanation of A CA is true but R is false DA is false but R is true

Q8. With respect to virtual memory:
Statement I: Address translation is performed for every logical address used during the execution of a program.
Statement II: A program can execute only when all of its components are loaded in memory.

Q9. A virtual memory system uses the first-in first-out page replacement policy and allocates a fixed number of frames to a process.
Assertion A: Increasing the number of page frames allocated to a process sometimes increases the page fault rate.
Reason R: Some programs do not exhibit locality of reference.

ABoth A and R are true and R is the correct explanation of A BBoth A and R are true but R is NOT the correct explanation of A CA is true but R is false DA is false but R is true

Q10. Consider the following arrival and burst times for three processes P0, P1, P2. The pre-emptive shortest job first algorithm is used, and scheduling is carried out only at the arrival or completion of a process. What is the average waiting time for the three processes?

Process	Arrival time	Burst time
P0	0 ms	7
P1	1 ms	3
P2	2 ms	7

A3 ms B3.67 ms C4.47 ms D4 ms

Q11. Match List I with List II

List I	List II
A. RAID level 2	I. Bit interleaved parity
B. RAID level 4	II. Block interleaved distributed parity
C. RAID level 5	III. Error correcting parity
D. RAID level 3	IV. Block interleaved parity

AA-IV, B-III, C-I, D-II BA-III, B-IV, C-II, D-I CA-III, B-I, C-II, D-IV DA-I, B-III, C-IV, D-I

Q12. Match List I with List II

List I	List II
A. Critical region	I. Hoare's monitor
B. Wait/signal	II. Mutual exclusion
C. Working set	III. Principle of locality
D. Deadlock	IV. Circular wait

AA-IV, B-I, C-III, D-II BA-II, B-I, C-III, D-IV CA-I, B-II, C-III, D-IV DA-IV, B-III, C-I, D-II

Q13. At a particular time of computation, the value of a counting semaphore is 7. Then 20 P operations and x V operations were completed on this semaphore. If the final value of the semaphore is 5, x will be

A15 B22 C18 D13

Q14. Requests to access cylinders occur in the sequence 4, 34, 10, 7, 19, 73, 2, 15, 6, 20. The head is currently at cylinder 50, and it takes 1 ms to move between adjacent cylinders. What is the time taken to satisfy all requests with the shortest-seek-time-first policy?

A119 ms B120 ms C142 ms D146 ms

Directions (Q91–95): Consider the following program fragment that deals with a table T with 17 rows and 1024 columns, computing an average for each column and printing it (i is the row index and j is the column index):

for j = [0...1023] {
  temp = 0;
  for i = [0...16]
    temp = temp + T[i][j];
  print(temp / 17.0);
}

T[i][j] and temp are 32-bit floating-point values and memory is word addressable. temp is kept in a processor register, so accessing temp does not involve a memory reference. The main memory is paged and holds 16 pages of 1024 words each. The page replacement policy is least recently used (LRU). Unless stated otherwise, T is stored in the virtual address space in row-major format.

Q15. Consider now that T is stored in column-major format. What is the main memory hit ratio?

A80% B95.6% C97.8% D99.9%

for j = [0...1023] {
  temp = 0;
  for i = [0...16]
    temp = temp + T[i][j];
  print(temp / 17.0);
}

Q16. Consider that T is stored in column-major format. How many page faults will be encountered?

A14 B15 C16 D17

for j = [0...1023] {
  temp = 0;
  for i = [0...16]
    temp = temp + T[i][j];
  print(temp / 17.0);
}

Q17. With T stored in row-major format, how many page faults will be encountered?

A16,402 B17,408 C18,208 D18,608

for j = [0...1023] {
  temp = 0;
  for i = [0...16]
    temp = temp + T[i][j];
  print(temp / 17.0);
}

Q18. What is the ratio of page faults for the row-major to the column-major arrangement?

A1024 : 1 B1301 : 1 C1240 : 1 D9107 : 8

for j = [0...1023] {
  temp = 0;
  for i = [0...16]
    temp = temp + T[i][j];
  print(temp / 17.0);
}

Q19. With T stored in row-major format, what is the main memory hit ratio?

A0 B1 C2 D3

Q20. The order of steps of address translation in the Linux virtual memory scheme will be:
A. Register
B. Offset
C. Page directory
D. Page table
E. Page middle directory
Choose the correct answer from the options given below:

AB, A, D, E, C BA, C, E, D, B CD, C, A, B, E DC, A, D, E, B

Q21. The sequence of steps for a page-replacement algorithm will be:
A. Find a frame that is not currently being used
B. Change the page table
C. Use the freed frame
D. No frame is free
E. Free a frame
Choose the correct answer from the options given below:

AD, A, E, B, C BE, B, A, C, D CB, E, A, D, C DD, E, B, A, C

Q22. Which of the following control problems does NOT exist when processes are unaware of each other during interaction?

AMutual exclusion BData coherence CStarvation DDeadlock

Q23. Match List I with List II

List I	List II
A. Batch Multiprogramming	I. Allows more efficient use of main memory
B. Time sharing	II. User no longer has direct access to the processor
C. Monitor	III. Maximize processor use
D. Reentrant Procedures	IV. Minimize response time

AA-III, B-II, C-IV, D-I BA-III, B-IV, C-II, D-I CA-I, B-III, C-IV, D-II DA-II, B-I, C-IV, D-III

Q24. Match List I with List II

List I	List II
A. RAID level-2	I. Block-interleaved
B. RAID level-3	II. Error-correcting-code
C. RAID level-4	III. Reed-Solomon codes
D. RAID level-6	IV. Bit-interleaved

AA-I, B-III, C-IV, D-II BA-II, B-IV, C-I, D-III CA-IV, B-I, C-II, D-III DA-II, B-III, C-IV, D-I

Q25. Match List I with List II (thread operations)

List I	List II
A. Thread spawn	I. To convert a blocking system call into a non-blocking call
B. Block thread	II. To reclaim pages
C. Jacketing	III. Processor turns to the execution of another ready thread
D. Flush	IV. Thread is provided with its own register context

AA-I, B-III, C-IV, D-II BA-IV, B-III, C-II, D-I CA-IV, B-III, C-I, D-II DA-II, B-I, C-IV, D-III