Operating Systems MCQs – Set-1 | 50 questions on OS functions, processes, memory, files, device management, security, and startup.
Mixed difficulty · Select one answer and open each explanation to review the concept.
What is the operating system’s central role?
A Manage hardware and software resources
B Create computer hardware
C Print every document
D Replace application programs
Answer: A. Manage hardware and software resources. An operating system coordinates hardware resources and provides services for applications and users.
Which component forms the core of an operating system?
A Shell
B Kernel
C Desktop wallpaper
D File extension
Answer: B. Kernel. The kernel is the central OS component that manages essential system operations.
What does a process scheduler allocate?
A Disk labels
B Screen pixels
C CPU time
D Battery capacity
Answer: C. CPU time. A process scheduler allocates processor time among runnable processes or threads.
What happens during a context switch?
A The screen changes resolution
B A file is compressed
C A cable changes ports
D Save and restore task state
Answer: D. Save and restore task state. A context switch saves one task’s execution state and restores another’s so the processor can switch work.
What is a process?
A A running program instance
B A user password
C A file extension
D A hardware socket
Answer: A. A running program instance. A process is an instance of a program that is executing.
What is a thread within a process?
A A storage volume
B An execution path
C A network protocol
D A user account
Answer: B. An execution path. A thread is an execution path within a process.
Which feature gives each process an address-space abstraction?
A File permissions
B Device drivers
C Virtual memory
D Disk formatting
Answer: C. Virtual memory. Virtual memory gives processes a managed address space that the operating system maps to physical memory.
Which technique moves memory pages between RAM and backing storage?
A Authentication
B Scheduling
C File indexing
D Paging
Answer: D. Paging. Paging moves fixed-size memory pages between physical memory and backing storage when needed.
What organizes files and directories on a storage device?
A File system
B Process scheduler
C Device driver
D User interface
Answer: A. File system. A file system organizes and retrieves files and directories.
How does a directory help organize a computer’s files?
A It schedules processor time
B It groups files and folders
C It powers external devices
D It renders screen images
Answer: B. It groups files and folders. Directories organize files and can contain subdirectories.
What do file permissions define?
A Screen brightness
B Network speed
C Allowed file actions
D Processor temperature
Answer: C. Allowed file actions. File permissions specify which actions users or processes may perform on a file.
Which software component helps the OS communicate with a device?
A Shell
B Kernel panic
C File manager
D Device driver
Answer: D. Device driver. A device driver enables communication between the operating system and a hardware device.
How does an application request a protected OS service?
A Through a system call
B By changing the CPU socket
C By opening a screen pixel
D Through a file extension
Answer: A. Through a system call. Applications use system calls to request services provided by the operating system.
What lets a user interact with an operating system?
A Power supply
B User interface
C Drive partition
D Memory bus
Answer: B. User interface. A user interface provides ways for people to interact with the operating system.
Which interface presents windows, icons, and menus?
A Command-line interface
B Device driver
C Graphical user interface
D System log
Answer: C. Graphical user interface. A graphical user interface presents visual controls such as windows, icons, and menus.
Which interface accepts typed text commands?
A Desktop wallpaper
B File system
C System service
D Command-line interface
Answer: D. Command-line interface. A command-line interface accepts commands entered as text.
What is a shell commonly used for?
A Execute commands through shell
B Store long-term backups
C Display hardware temperatures only
D Connect power cables
Answer: A. Execute commands through shell. A shell accepts commands or scripts and requests operating-system services.
What does user authentication establish?
A Which files should be compressed
B A user’s claimed identity
C Which display to connect
D The CPU’s clock rate
Answer: B. A user’s claimed identity. Authentication verifies a user’s identity, commonly using credentials or another authentication method.
After identity is verified, what does authorization determine?
A Screen layout
B Memory size
C Permitted actions
D Device color
Answer: C. Permitted actions. Authorization determines what an authenticated user or process is allowed to access or do.
What can an access control list specify?
A Processor instructions
B File compression ratio
C Network cable length
D Permissions for an object
Answer: D. Permissions for an object. An access control list associates an object with identities and permitted actions.
Which OS subsystem supports network communication?
A Network protocol stack
B Desktop theme
C File extension
D Print queue
Answer: A. Network protocol stack. The operating system’s networking components support communication using network protocols.
What is a background service?
A A removable drive
B A background program
C A monitor setting
D A keyboard layout
Answer: B. A background program. A service is a program that runs in the background to provide a system or application function.
Which execution mode has privileged access to core system operations?
A User mode
B Safe mode
C Kernel mode
D Sleep mode
Answer: C. Kernel mode. Kernel mode allows privileged code to perform core operating-system and hardware operations.
Where do ordinary applications usually run with restricted privileges?
A Firmware mode
B Boot mode
C Recovery mode
D User mode
Answer: D. User mode. Applications generally run in user mode, where access to protected system resources is restricted.
Why does an operating system keep event logs?
A Record system events and errors
B To increase memory capacity
C To rename hardware ports
D To speed up the monitor
Answer: A. Record system events and errors. System logs record events that help with monitoring, troubleshooting, and auditing.
Which tool commonly shows running processes and resource use?
A File compressor
B Task manager
C Code compiler
D Image scanner
Answer: B. Task manager. A task manager can display running processes and their resource use.
What does a process priority influence?
A Which files are encrypted
B How much storage is installed
C Scheduling preference
D Monitor refresh rate
Answer: C. Scheduling preference. Scheduling priority can influence which runnable task receives processor time sooner.
What is a deadlock in operating systems?
A A locked user account
B A powered-off monitor
C A full storage drive
D Tasks wait on held resources
Answer: D. Tasks wait on held resources. A deadlock occurs when tasks wait on resources held by one another so none can proceed.
What is a real-time operating system designed to meet?
A Timing deadlines predictably
B Unlimited storage growth
C Maximum screen brightness
D Every network request instantly
Answer: A. Timing deadlines predictably. Real-time systems are designed to respond within defined timing constraints.
How does time-sharing let many users or tasks use a system?
A Copies the CPU
B It rapidly shares processor time
C Stores each task in ROM
D It disables task scheduling
Answer: B. It rapidly shares processor time. Time-sharing rapidly allocates processor time among tasks so they can make progress interactively.
How does a batch operating system typically process submitted jobs?
A With continuous touch input
B Single graphical window
C Groups jobs for later execution
D Only through voice commands
Answer: C. Groups jobs for later execution. Batch systems process groups of jobs with limited direct interaction during execution.
What is one function of OS device management?
A Compose application source code
B Choose file names automatically
C Print a system’s license
D Coordinate input and output devices
Answer: D. Coordinate input and output devices. Device management coordinates hardware devices and provides software with controlled ways to use them.
What does a file handle represent to a program?
A An open file reference
B A processor core
C A network address
D A screen coordinate
Answer: A. An open file reference. A file handle is a reference an application uses to access an opened file or resource.
Why isolate processes from one another?
A To share passwords openly
B To limit unintended interference
C To remove all file permissions
D To slow processor scheduling
Answer: B. To limit unintended interference. Process isolation helps prevent one process from accidentally accessing or corrupting another’s memory.
What does memory protection help prevent?
A Low battery warnings
B Wrong screen colors
C Unauthorized memory access
D Slow file downloads
Answer: C. Unauthorized memory access. Memory protection restricts processes from accessing memory areas they do not own or have permission to use.
What usually starts after firmware completes its initial setup?
A A document editor
B The file recycle bin
C A user application
D The boot manager or loader
Answer: D. The boot manager or loader. After firmware initialization, boot logic selects a boot target and starts the operating-system loader.
Which firmware component follows configured boot order?
A UEFI boot manager
B Text editor
C Task manager
D Disk cleanup utility
Answer: A. UEFI boot manager. The UEFI boot manager uses configured boot-order variables to choose drivers or applications such as an OS loader.
What does hibernation generally do before powering down?
A Deletes temporary user files
B Saves session state to storage
C Keeps work in RAM
D Uninstalls running applications
Answer: B. Saves session state to storage. Hibernation writes system state to storage so the session can be restored after power is removed.
What usually happens to a session during sleep mode?
A Converted to printed output
B It is erased from memory
C It remains in low-power memory
D Copied to USB drive
Answer: C. It remains in low-power memory. Sleep keeps the session available in low-power memory so the system can resume quickly.
What does restarting an operating system do?
A Formats the system drive
B Changes all user permissions
C Uninstalls the kernel
D Shuts down and boots again
Answer: D. Shuts down and boots again. Restarting shuts down the current operating-system session and starts the system again.
Why install operating-system updates?
A Receive fixes and improvements
B Increase physical memory modules
C Replace the motherboard
D Change monitor dimensions
Answer: A. Receive fixes and improvements. Updates can provide bug fixes, security improvements, and other changes.
What is a recovery environment intended to help with?
A Edit video files
B Repair or restore a system
C Connect a printer
D Measure CPU voltage
Answer: B. Repair or restore a system. A recovery environment provides tools to diagnose, repair, or restore an operating system.
Which statement best describes a 64-bit OS?
A It has exactly 64 applications
B Exactly 64 folders
C Wider address space
D It requires a 64-inch display
Answer: C. Wider address space. A 64-bit operating system supports a wider address space than a 32-bit system, subject to hardware and OS limits.
Which layer accepts user commands and invokes system services?
A Power supply
B File allocation table
C Memory controller
D Shell
Answer: D. Shell. A shell provides a command interface and invokes operating-system services.
What can a multiuser operating system support?
A Separate accounts using shared resources
B Only one account forever
C No access permissions
D Only offline software
Answer: A. Separate accounts using shared resources. A multiuser operating system supports multiple user accounts and manages their access to shared resources.
Which OS capability lets several applications make progress at once?
A Disk encryption
B Multitasking
C File compression
D Screen mirroring
Answer: B. Multitasking. Multitasking schedules processor time and resources among multiple active applications.
How can multiple threads in one process differ from separate processes?
A Threads have separate OSes
B Processes share every memory address
C Share process address space
D Threads require separate computers
Answer: C. Share process address space. Threads in one process share its address space, while separate processes are isolated from one another.
What do containers commonly share with their host?
A A separate physical CPU
B Every user password
C An independent motherboard
D The host operating-system kernel
Answer: D. The host operating-system kernel. Containers isolate applications while sharing the host operating-system kernel.
What does a virtual machine present to a guest operating system?
A Virtualized hardware resources
B Only a printer queue
C A physical cooling fan
D A shared file extension
Answer: A. Virtualized hardware resources. A virtual machine presents virtualized hardware on which a guest operating system can run.
What distinguishes a real-time OS from a general-purpose OS?
A It never uses memory
B Predictable timing deadlines
C It cannot run applications
D It works only without hardware
Answer: B. Predictable timing deadlines. Real-time operating systems prioritize predictable responses within timing constraints.