100 Operating Systems MCQs with Answers (Multiple Choice Questions for Exams & Competitive Tests). Prepare for exams with these 100 Operating Systems MCQs with answers. This comprehensive set of multiple-choice questions covers process management, memory management, scheduling, deadlock, file systems, real-time OS, Linux, and more perfect for computer science students, IT exams, and competitive tests.
Operating Systems (OS) are one of the most important subjects in computer science and information technology. Whether you are preparing for university exams, competitive tests, job interviews, or IT certifications, having a strong understanding of operating system concepts is essential. This collection of 100 Operating Systems MCQs with answers covers key topics such as process management, memory management, CPU scheduling, deadlocks, file systems, virtual memory, real-time operating systems, Linux basics, and more. These multiple-choice questions are carefully designed to help students revise core concepts, improve problem-solving skills, and confidently prepare for computer science exams and competitive IT tests.
✅ Operating Systems – 100 MCQs with Answers
1. What is an Operating System?
A) Application software
B) System software
C) Programming language
D) Compiler
Answer: B
2. Which of the following is not an Operating System?
A) Windows
B) Linux
C) Oracle
D) macOS
Answer: C
3. The core of an operating system is called:
A) Shell
B) Kernel
C) Command
D) Interface
Answer: B
4. Which OS is open-source?
A) Windows
B) macOS
C) Linux
D) DOS
Answer: C
5. Which component manages memory?
A) File system
B) Process manager
C) Memory manager
D) Compiler
Answer: C
6. A process is:
A) A program in execution
B) A file
C) A folder
D) A device
Answer: A
7. Which scheduling algorithm uses time slices?
A) FCFS
B) Round Robin
C) SJF
D) Priority
Answer: B
8. FCFS stands for:
A) First Come First Serve
B) First Control First System
C) Fastest Come Fast Serve
D) File Control First System
Answer: A
9. Which is a non-preemptive scheduling algorithm?
A) Round Robin
B) Priority (Preemptive)
C) FCFS
D) Multilevel Queue
Answer: C
10. Virtual memory uses:
A) RAM only
B) Hard disk
C) Cache
D) Register
Answer: B
11. Paging avoids:
A) External fragmentation
B) Internal fragmentation
C) Deadlock
D) Starvation
Answer: A
12. Thrashing occurs due to:
A) Excessive paging
B) Overheating
C) Virus attack
D) Power failure
Answer: A
13. A deadlock occurs when:
A) CPU is idle
B) Processes wait indefinitely
C) Memory is full
D) Disk crashes
Answer: B
14. How many conditions are required for deadlock?
A) 2
B) 3
C) 4
D) 5
Answer: C
15. Mutual exclusion means:
A) Shared resource
B) Only one process at a time
C) All processes execute
D) No waiting
Answer: B
16. Which is not a type of OS?
A) Batch OS
B) Real-time OS
C) Distributed OS
D) Compiler OS
Answer: D
17. Real-time OS is used in:
A) Banking
B) Gaming
C) Embedded systems
D) Word processing
Answer: C
18. Which OS supports multiple users?
A) Single-user OS
B) Multi-user OS
C) Batch OS
D) Embedded OS
Answer: B
19. GUI stands for:
A) Graphical User Interface
B) General User Input
C) Graphical Unified Interface
D) Global User Interface
Answer: A
20. CLI stands for:
A) Command Line Interface
B) Control Line Input
C) Computer Line Interface
D) Command Link Interface
Answer: A
(Continuing…)
21. Which is a mobile OS?
A) Windows 10
B) Android
C) Ubuntu
D) Fedora
Answer: B
22. Which company developed Windows?
A) Apple
B) IBM
C) Microsoft
D) Google
Answer: C
23. Which is a macOS developer?
A) Google
B) Apple
C) IBM
D) Intel
Answer: B
24. File system manages:
A) CPU
B) Files and directories
C) Memory
D) Printer
Answer: B
25. Context switching means:
A) Changing program
B) Saving and loading process state
C) Shutting down
D) Formatting disk
Answer: B
26. Which is secondary storage?
A) RAM
B) Cache
C) Hard Disk
D) Register
Answer: C
27. RAM is:
A) Permanent
B) Volatile
C) External
D) Optical
Answer: B
28. Which scheduling gives minimum average waiting time?
A) FCFS
B) SJF
C) Round Robin
D) FIFO
Answer: B
29. Starvation occurs in:
A) FCFS
B) Priority Scheduling
C) Round Robin
D) FIFO
Answer: B
30. Aging prevents:
A) Deadlock
B) Starvation
C) Thrashing
D) Paging
Answer: B
31. Multiprogramming means:
A) One program
B) Many programs in memory
C) No memory
D) Single user
Answer: B
32. Multitasking allows:
A) One task
B) Two CPUs
C) Multiple tasks
D) No tasks
Answer: C
33. Spooling is related to:
A) CPU
B) Printer
C) Memory
D) Cache
Answer: B
34. Semaphore is used for:
A) Memory
B) Synchronization
C) File system
D) Disk
Answer: B
35. Critical section problem relates to:
A) CPU speed
B) Process synchronization
C) Disk size
D) Compiler
Answer: B
36. Which is not a scheduling criteria?
A) Throughput
B) Turnaround time
C) Waiting time
D) Hard disk size
Answer: D
37. Turnaround time is:
A) Completion – Arrival
B) Arrival – Completion
C) CPU – Memory
D) Waiting + Arrival
Answer: A
38. Which device is input?
A) Printer
B) Monitor
C) Keyboard
D) Speaker
Answer: C
39. Which OS is best for servers?
A) Linux
B) DOS
C) Windows 98
D) Android
Answer: A
40. Interrupt is:
A) Error
B) Signal to CPU
C) File
D) Program
Answer: B
41. Which memory is fastest?
A) RAM
B) Cache
C) Hard Disk
D) ROM
Answer: B
42. Which OS uses kernel architecture?
A) Linux
B) Windows
C) macOS
D) All of these
Answer: D
43. Booting means:
A) Installing OS
B) Starting computer
C) Deleting files
D) Formatting disk
Answer: B
44. Cold boot means:
A) Restart
B) Power on from off state
C) Sleep mode
D) Hibernate
Answer: B
45. Warm boot means:
A) Restart
B) Shutdown
C) Hibernate
D) Sleep
Answer: A
46. Which manages CPU?
A) Scheduler
B) Compiler
C) Loader
D) Linker
Answer: A
47. Loader loads program into:
A) CPU
B) RAM
C) ROM
D) Cache
Answer: B
48. Which is example of real-time OS?
A) Windows
B) VxWorks
C) Linux Mint
D) DOS
Answer: B
49. Distributed OS manages:
A) Single computer
B) Multiple computers
C) Printer
D) Disk only
Answer: B
50. The smallest unit of data in OS is:
A) Bit
B) Byte
C) KB
D) MB
Answer: A
51. Which component handles input/output devices?
A) Scheduler
B) Device Driver
C) Compiler
D) Loader
Answer: B
52. Which is an example of a single-user operating system?
A) Windows Server
B) UNIX
C) MS-DOS
D) Linux
Answer: C
53. A time-sharing system allows:
A) One user at a time
B) Multiple users simultaneously
C) No user interaction
D) Only batch processing
Answer: B
54. Internal fragmentation occurs in:
A) Paging
B) Fixed partitioning
C) Segmentation
D) Virtual memory
Answer: B
55. External fragmentation occurs in:
A) Fixed partitioning
B) Paging
C) Dynamic partitioning
D) Cache memory
Answer: C
56. Deadlock prevention works by:
A) Ignoring deadlock
B) Detecting deadlock
C) Avoiding at least one necessary condition
D) Restarting system
Answer: C
57. The Banker’s Algorithm is used for:
A) Scheduling
B) Memory allocation
C) Deadlock avoidance
D) File management
Answer: C
58. A page fault occurs when:
A) CPU is overloaded
B) Page is not found in memory
C) Disk fails
D) Cache is full
Answer: B
59. Swapping moves a process from:
A) CPU to RAM
B) RAM to Disk
C) Disk to CPU
D) Cache to RAM
Answer: B
60. Which of the following is NOT a type of memory?
A) RAM
B) ROM
C) Cache
D) Compiler
Answer: D
61. Kernel mode is also known as:
A) User mode
B) Safe mode
C) Privileged mode
D) Normal mode
Answer: C
62. User mode is:
A) Restricted mode
B) Full access mode
C) Kernel mode
D) Supervisor mode
Answer: A
63. The shell in an operating system provides:
A) Memory management
B) Hardware control
C) Interface between user and kernel
D) File storage
Answer: C
64. Which of the following is NOT a Linux distribution?
A) Ubuntu
B) Fedora
C) Photoshop
D) Debian
Answer: C
65. Ubuntu is based on:
A) Windows
B) UNIX
C) Linux
D) DOS
Answer: C
66. Android operating system is based on:
A) Windows kernel
B) UNIX
C) Linux kernel
D) DOS
Answer: C
67. iOS is developed by:
A) Microsoft
B) Google
C) Apple
D) IBM
Answer: C
68. Which of the following is NOT a CPU scheduling algorithm?
A) FCFS
B) Round Robin
C) SJF
D) Linking
Answer: D
69. FIFO scheduling is the same as:
A) SJF
B) Round Robin
C) FCFS
D) Priority
Answer: C
70. Which technique is used to prevent starvation?
A) Deadlock detection
B) Aging
C) Paging
D) Segmentation
Answer: B
71. Multithreading means:
A) Multiple CPUs
B) Multiple programs
C) Multiple threads within a process
D) Multiple users
Answer: C
72. A thread is also called:
A) Heavyweight process
B) Lightweight process
C) System call
D) Program counter
Answer: B
73. A race condition occurs when:
A) CPU runs fast
B) Processes compete for shared data
C) Memory is full
D) Disk crashes
Answer: B
74. Protection in OS is mainly for:
A) Speed
B) Security
C) Size
D) Power
Answer: B
75. Encryption is used to ensure:
A) Speed
B) Confidentiality
C) Storage
D) Compilation
Answer: B
76. Which is an open-source operating system?
A) Windows
B) macOS
C) Linux
D) iOS
Answer: C
77. Which OS is commonly used in ATMs?
A) Batch OS
B) Real-time OS
C) Time-sharing OS
D) Distributed OS
Answer: B
78. Batch processing means:
A) Continuous user interaction
B) Manual execution
C) No direct user interaction
D) Real-time processing
Answer: C
79. Which Linux command is used to list files?
A) dir
B) ls
C) list
D) show
Answer: B
80. Which command is used to create a directory in Linux?
A) create
B) md
C) mkdir
D) newdir
Answer: C
81. NTFS is a type of:
A) Processor
B) File system
C) Memory
D) Kernel
Answer: B
82. FAT stands for:
A) File Access Table
B) File Allocation Table
C) Fast Access Table
D) File Application Table
Answer: B
83. Virtual memory increases:
A) Physical memory
B) CPU speed
C) Apparent memory size
D) Cache size
Answer: C
84. CPU utilization measures:
A) Disk usage
B) Memory usage
C) CPU busy time
D) File size
Answer: C
85. Throughput refers to:
A) Memory size
B) Number of processes completed per unit time
C) CPU speed
D) Disk capacity
Answer: B
86. Waiting time is:
A) Time spent executing
B) Time spent in ready queue
C) Time spent in disk
D) Time spent in cache
Answer: B
87. Response time is most important in:
A) Batch systems
B) Interactive systems
C) Embedded systems
D) Offline systems
Answer: B
88. Paging uses:
A) Variable-size blocks
B) Fixed-size pages
C) Dynamic memory
D) Cache memory
Answer: B
89. Segmentation uses:
A) Fixed size
B) Variable size segments
C) Cache blocks
D) Disk sectors
Answer: B
90. Cache memory is:
A) Large and slow
B) Small and fast
C) Permanent
D) External
Answer: B
91. An operating system acts as a:
A) Compiler
B) Resource manager
C) Application
D) Text editor
Answer: B
92. BIOS is stored in:
A) RAM
B) Cache
C) ROM
D) Hard disk
Answer: C
93. BIOS is an example of:
A) Application software
B) Firmware
C) Utility software
D) Driver
Answer: B
94. Interrupt vector stores:
A) File names
B) Memory addresses of ISRs
C) CPU speed
D) Disk size
Answer: B
95. Which of the following is NOT an OS service?
A) Process management
B) Memory management
C) Compiling programs
D) File management
Answer: C
96. IPC stands for:
A) Internal Process Control
B) Inter-Process Communication
C) Integrated Program Code
D) Input Process Command
Answer: B
97. A pipe is used for:
A) Scheduling
B) File storage
C) Inter-process communication
D) Memory allocation
Answer: C
98. A zombie process is:
A) Running process
B) Sleeping process
C) Terminated but not removed from process table
D) Blocked process
Answer: C
99. An orphan process is adopted by:
A) Scheduler
B) Kernel
C) Init process
D) BIOS
Answer: C
100. The main goal of an operating system is:
A) Increase hardware cost
B) Reduce memory
C) Efficient resource management
D) Delete files
Answer: C
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