Operating System GATE Questions

A highly popular method used to master all the concepts from the topic, Operating System, is to practise hard all these Operating System GATE Questions. Candidates can also learn more about the concepts covered in this topic, such as Memory Management, Deadlocks and Process Concepts and CPU scheduling and so on. We have attempted to compile, here in this article, a collection of GATE Questions on the Operating System.

Candidates are urged to practise these Operating System GATE previous year questions so that they will get the best results. Operating System is an important topic in the GATE CSE question paper, and solving these questions will help the candidates to prepare more proficiently for the GATE exams. Meanwhile, candidates can find the GATE Questions for Operating System here, in this article below, to solve and practise before the exams. They can also refer to these GATE previous year question papers and start preparing for the exams.

Note: We will be updating the answers to these questions very soon.

GATE Questions Operating System

From The Operating System Topic of the GATE CSE Question Paper

MCQ- Single Answer Questions

1.Which among these below is not a valid deadlock prevention scheme?

(a) Release all resources before requesting a new resource

(b) Number the resources uniquely and never request a lower numbered resource than the last one requested

(c) Never request a resource after releasing any resource

(d) Request and all required resources be allocated before execution

2.Which among these requires a device driver?

a) Register

b) Cache

c) Main memory

d) Disk

3.Given below are some events that take place after a device controller issues an interrupt while process L is under execution.

(P) The processor pushes the process status of L onto the control stack.

(Q) The processor finishes the execution of the current instruction.

(R) The processor executes the interrupt service routine.

(S) The processor pops the process status of L from the control stack.

(T) The processor loads the new PC value based on the interrupt.

Choose from the options below for the correct order in which the events above occur.

(a) QTPRS

(b) PTRSQ

(c) TRPQS

(d) QPTRS

4.A system has 6 identical resources and N processes competing for them. Each process can request at most 2 resources. Name the following values of N that could lead to a deadlock.

(a) 1

(b) 3

(c) 2

(d) 4

5.In UNIX, which from the following command is used to set the task priority?

(a) PS

(b) NICE

(c) Init

(d) Kill

6.Which among these is a spooled device?

(a) A graphic display device

(b) A line printer that is used to print the output of a number of jobs

(c) A secondary storage device in a virtual memory system

(d) A terminal use to enter the input data to a running program

7.Which among these conditions does not hold good for a solution to a critical section program?

(a) No two processes may be simultaneously inside their critical sections

(b) Processes do not wait forever to enter its critical section

(c) No assumptions may be made about speeds of the number of CPUs

(d) Processes running outside its critical section may block other processes

8.Which of the following is used to invoke system calls?

(a) An indirect jump

(b) A software interrupt

(c) A privileged instruction

(d) Polling

9.Given that at a particular time of computation, the value of a counting semaphore is 7, then if 20 P operations and 15 V operations were completed on this semaphore, what is the resulting value of the semaphore?

(a) 12

(b) 2

(c) 7

(d) 42

10.Which of the following is not a valid scheme for deadlock prevention?

(a) Never request a resource after releasing a resource

(b) Release all resources before requesting a new resource

(c) Number the resources uniquely and never request a lower numbered resource than the last one requested

(d) Request and all required resources be allocated before execution

11.What is dirty bit used to show?

(a) Page with corrupted data

(b) Wrong page

(c) Page with low frequency occurrence

(d) Page that is modified after being loaded into cache memory

12.What are the essential contents in each entry of a page table?

(a) Page frame number

(b) Both virtual page number and page frame number

(c) Virtual page number

(d) Access right information

13.Which of the below statements are False?

(a) User level threads are not scheduled by the kernel

(b) Context switching between user level threads is faster than context switching between kernel level threads

(c) When a user level thread is blocked, all other threads of its process are blocked

(d) Kernel level threads cannot share the code segment

14.What does the principle of locality justify the use of?

(a) Cache memory

(b) Polling

(c) Interrupts

(d) DMA

15.A critical section is a program segment________

(a) where shared resources are accessed

(b) which should run in a certain specified amount of time

(c) which avoids deadlocks

(d) which must be enclosed by a pair of semaphore operations, P and V

16.What happens to the CPU on receiving an interrupt from an IO device?

(a) hand over control of address bus and data bus to the interrupting device

(b) branches off to the interrupt service routine after completion of the current instruction

(c) halts for predetermined time

(d) branches off to the interrupt service routine immediately

17.Which of the following is the most popular 16-ibit operating system?

(a) TRS-DOS

(b) CP/M

(c) MS-DOS

(d) UNIX

18.When a process executes the code

fork();

fork();

fork();

What are the total number of child processes created?

(a) 7

(b) 3

(c) 8

(d) 4

19.Which of the below given system calls results in the sending of SYN packets?

(a) listen

(b) socket

(c) connect

(d) bind

20.When a process has been allocated 3-page frames, none of the pages of the process are available in the memory initially. The process makes the following sequence of page references (reference string): 1, 2, 1, 3, 7, 4, 5, 6, 3, 1. Least Recently Used (LRU) page replacement policy is a practical approximation to optimal page replacement. For the above reference string, how many more page faults occur with LRU than with the optimal page replacement policy?

(a) 1

(b) 0

(c) 2

(d) 3

21.What is the amount of ROM needed to implement a 4 bit multiplier?

(a) 2 Kbits

(b) 1 Kbits

(c) 128 bits

(d) 64 bits

22._______ is the disk used to cold boot a PC.

(a) Setup disk

(b) Program disk

(c) Diagnostic disk

(d) Set up disk

23. _____ is the command used to set a name to a disk in DOS?

(a) VOL

(b) LABEL

(c) VOLUME

(d) DISKLABEL

24. Which one of the below statements is FALSE about SJF or Shortest Job First Scheduling?

S1: It causes minimum average waiting time

S2: It can cause starvation

(a) Neither S1 nor S2

(b) Only S1

(c) Both S1 and S2

(d) Only S2

25. When an input occurs, an operating system ______

(a) Always resumes execution of interrupted process after processing the interrupt

(b) Ignore the interrupt .

(c) May change state of interrupted process to “blocked” and schedule other process

(d) Always changes state of interrupted process after processing the interrupt

26. State whether the following statement is TRUE or FALSE with reason. The data transfer between memory and I/O devices using programmed I/O is faster than interrrupt-driven I/O.

1. True
2. False

27. The swap space resides in______

1. On chip-cache
2. RAM
3. Disk
4. ROM

28. If a computer has six tape drives, with n processes competing for them and each process may need two drives, what is the maximum value of n for the system to be deadlock free?

(a) 3

(b) 4

(c) 5

(d) 6

29. Which of these given below are the characteristics of UNIX?

(a) Multi-tasking

(b) Multi user

(c) Kernel Manages data

(d) All the above

30. Which of these given statements are true?

I. The shortest remaining time first scheduling may cause starvation

II. Pre-emptive scheduling may cause starvation

III. Round-robin is better than FCFS in terms of response time

(a) I and III only

(b) I, II and III

(c) I only

(d) II and III only

31. Which is the page replacement policy that sometimes leads to more page faults when the size of memory is increased?

1. FIFO
2. Optimal
3. LRU
4. None of the above

32. Match the pairs from the following list.

33. Under the paged memory management scheme, a simple lock and key memory protection arrangement may still be required, in case the___________ processors do not have an address mapping hardware.

34. What does formatting of a floppy disk refer to?

(a) Erasing the system area

(b) Arranging the data on the disk in contiguous fashion

(c) Writing identification information on all tracks and sectors

(d) Writing the directory

35. Consider a uniprocessor system executing three tasks T₁, T₂ and T₃, each of which is composed of an infinite sequence of jobs (or instances) which arrive periodically at intervals of 3, 7 and 20 milliseconds, respectively. The priority of each task is the inverse of its period, and the available tasks are scheduled in order of priority, with the highest priority task scheduled first. Each instance of T₁, T₂ and T₃ requires an execution time of 1, 2 and 4 milliseconds, respectively. Given that all tasks initially arrive at the beginning of the 1st millisecond and task pre-emptions are allowed, the first instance of T₃ completes its execution at the end of ______ milliseconds.

36. Given that a computer uses 46-bit virtual address, 32-bit physical address, and a three-level paged table organization. The page table base register stores the base address of the first-level table (T₁), which occupies exactly one page. Each entry of T₁ stores the base address of a page of the second-level table (T₂). Each entry of T₂ stores the base address of a page of the third-level table (T₃). Each entry of T₃ stores a page table entry (PTE). The PTE is 32 bits in size and the processor used in the computer has a 1 MB 16-way set associative virtually indexed physically tagged cache, if the cache block size is 64 bytes, what is the size of a page in KB in this computer?

(a) 4

(b) 2

(c) 16

(d) 8

37. What is distributed processing?

1. Solving computing problems by breaking them into smaller parts that are separately processed by different computers
2. Allowing users to share files on a network
3. Solving computer component problems from a different computer
4. Allowing users to access network resources away from the office

38. _________ is a command used to create a new file.

1. DCOPY COM
2. DCOPY COM.N
3. DCOPY COMN
4. COPY CON

39. Name the program in the operating system that does processor management.

1. Traffic controller
2. Process scheduler
3. Job scheduler
4. Dispatcher

40. If a system uses FIFO policy for page replacement, and it has 4-page frames with no pages loaded to begin with. Also, the system first accesses 100 distinct pages in some order and then accesses the same 100 pages but now in the reverse order, then how many page faults will occur?

1. 192
2. 195
3. 196
4. 197

41. Below, listed are some operating system abstractions (in the left column) and the hardware components. Which of these matching pairs are correct?

42. Which among these are file extensions in DOS?

1. BAT
2. EXE
3. COM
4. All of these

43. The data blocks of a very large file in the UNIX file system are allocated using____

1. Indexed allocation
2. Contiguous allocation
3. Linked allocation
4. An extension of indexed allocation

44. If only filenames and extensions are to be displayed in wide format, which command will you use?

1. Dir/b
2. Dir/w
3. Dir a:
4. Dir/s

45. An application loads 100 libraries at startup. Loading each library requires exactly one disk access. The seek time of the disk to a random location is given as 10 ms. Rotational speed of the disk is 6000 rpm. lf all 100 libraries are loaded from random locations on the disk, how long does it take to load all libraries? (The time to transfer data from the disk block once the head has been positioned at the start of the block may be neglected.)

(a) 0.50 s

(b) 1.00 s

(c) 1.25 s

(d) 1.50 s

46. _______ is not an advantage of multiprogramming.

1. Shorter response time
2. Ability to assign priorities to job
3. Decreased operating system overhead
4. Increased throughout

47. How are Copy and Xcopy same?

1. Both are external commands of DOS
2. Both can be used to copy a file or group of files
3. Both are internal commands of DOS
4. Both (a) and (c)

48. Why is RESTORE command used?

1. Restore files are used to
2. Restore files which were deleted recently
3. Restore files from recycle bin
4. Restore files from disks made using the BACKUP command

49. Embedded operating system is used_______

1. On a networked PC
2. On a mainframe
3. On a desktop operating system
4. On a PDA

50. What is the sequence of directories and subdirectories that the operating system must follow to find a specific file?

(a) Extension

(b) Path

(c) External command

(d) Internal command

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