It manages computer hardware and software resources.
It allows the user to interact with the computer.
Without an OS, a computer cannot work.
Definition
👉 An Operating System is a program that acts as an interface between the user and the computer hardware.
Examples
Windows
Linux
macOS
Android
iOS
Unix
🧠 Functions of an Operating System
Function
Simple Meaning
Example
Process Management
Handles running programs
Opening Chrome + Word together
Memory Management
Allocates RAM to programs
OS gives memory to apps
File Management
Manages files and folders
Create, delete, rename
Device Management
Controls input/output devices
Keyboard, mouse, printer
Security
Protects data and access
Password, antivirus
User Interface
Helps user interact
GUI with icons & windows
Error Handling
Detects & fixes errors
“Not responding” message
Resource Allocation
Shares resources fairly
CPU time sharing
Types of Operating Systems
Type of OS
Meaning
Example
Batch OS
Tasks collected & processed in batches (No user interaction)
Payroll processing
Time-Sharing OS
Many users share system at same time
Mainframes
Real-Time OS (RTOS)
Immediate response needed
Flight control, medical systems
Distributed OS
Uses multiple computers as one system
Cloud computing
Multi-user OS
Many users can use one system
Unix, Linux
Mobile OS
OS for smartphones
Android, iOS
Network OS
Controls computers in a network
Windows Server
Types of User Interfaces
Type
Full Form / Meaning
Examples
GUI
Graphical User Interface
Windows, Android
CLI
Command Line Interface
MS-DOS, Linux terminal
TUI
Text User Interface
Old systems
👨💻 Types of Processes
Process = Running program
Types:
Foreground process – Visible to user (Example: Browser)
Background process – Runs behind (Example: Antivirus scan)
🧠 Multitasking vs Multiprocessing vs Multithreading
Term
Meaning
Example
Multitasking
OS runs many tasks at same time
Songs + browsing
Multiprocessing
Many CPUs used together
Quad-core processor
Multithreading
Many parts of same program run parallel
Download + browse in browser
🔐 OS Security Features
Password protection
Firewalls
Encryption
Access permissions (Read / Write / Execute)
🖥 Memory Management Concepts
Term
Meaning
Primary memory (RAM)
Temporary storage
Secondary memory
Permanent storage
Virtual Memory
Uses hard disk as additional RAM
Paging
Memory divided into pages
Segmentation
Memory divided into segments
📁 File System Concepts
Term
Meaning
File
Collection of data
Directory / Folder
Stores files
Path
Address of file
File extension
Type of file (.doc, .exe, .txt)
🔌 Device Management
OS manages I/O devices.
Uses Device Drivers (software that runs hardware).
Example: Printer driver, Sound driver.
⭐ Important Terms
Term
Simple Meaning
Kernel
Core of the OS, controls hardware
Shell
Interface between user & OS
Booting
Starting the computer
Cold boot
Power ON boot
Warm boot
Restart boot
Deadlock
Two processes waiting for each other forever
📍 Most Important Points
OS = Interface between User & Hardware
Kernel = Heart of OS
GUI vs CLI
Virtual memory
Multi-user & Multitasking systems
Batch, Real-time, Distributed OS
Booting (Cold/Warm)
Device Drivers
Deadlock
🧠 OPERATING SYSTEM – MIND MAP SUMMARY
┌──────────────────────┐
│ OPERATING SYSTEM │
│ (Interface between │
│ User & Hardware) │
└──────────────────────┘
│
┌──────────────────────────────────────────┼──────────────────────────────────────────┐
│ │ │
┌──────┴───────┐ ┌───────┴────────┐ ┌─────────┴────────┐
│ FUNCTIONS │ │ COMPONENTS │ │ TYPES OF OS │
└──────┬───────┘ └────────┬────────┘ └─────────┬────────┘
│ │ │
│ │ │
Process Mgmt Kernel (Core of OS) Batch OS
Memory Mgmt Shell (Command Interface) Real-Time OS
File Mgmt File System Distributed OS
Device Mgmt Drivers Time-Sharing OS
Security Bootloader / BIOS Multiuser OS
UI (GUI/CLI) Mobile OS
Error Handling Network OS
Resource Allocation
🎯 KEY CONCEPTS
PROCESS → Running program
THREAD → Part of process (lightweight)
MULTITASKING → Many tasks at same time
MULTIPROCESSING → Many CPUs
MULTITHREADING → Many threads inside one program
🧠 MEMORY MANAGEMENT
RAM (Volatile)
ROM (Permanent)
CACHE (Fastest)
VIRTUAL MEMORY (Hard Disk used as RAM)
Paging → Fixed size pages
Segmentation → Logical segments (code, data, stack)
Thrashing → Excessive paging swapping
📁 FILE & DEVICE MANAGEMENT
File = Data storage
Directory = Folder storing files
Driver = Software controlling hardware
Spooling = Print queue system (Printer)
Operating System is a type of: A) Application Software B) System Software C) Firmware D) Utility Software Answer: b
Which of the following is NOT an operating system? A) Linux B) Windows C) Android D) Oracle Answer: d
The OS works as an interface between: A) User and Hardware B) Mouse and Keyboard C) RAM and ROM D) Printer and Scanner Answer: a
Which of the following controls execution of programs? A) Compiler B) Operating System C) Assembler D) Linker Answer: b
Which OS is an example of open-source software? A) Windows B) macOS C) Linux D) iOS Answer: c
The core component of OS is called: A) Shell B) Kernel C) Application D) Processor Answer: b
Android OS is based on: A) UNIX B) Windows C) Linux kernel D) Macintosh Answer: c
MS-DOS is a type of: A) GUI OS B) CLI OS C) Real-time OS D) Distributed OS Answer: b
The primary purpose of an OS is to: A) Format disks B) Manage hardware and software resources C) Run applications faster D) Remove viruses Answer: b
Which OS does Apple use in Mac computers? A) Ubuntu B) macOS C) Solaris D) Fedora Answer: b
GUI stands for: A) Global User Interface B) Graphical User Interface C) Graphics Utility Interface D) General Utility Input Answer: b
iOS is used in: A) Android phones B) Apple devices C) Windows PC D) Banking servers Answer: b
Which OS is used mainly for servers & supercomputers? A) Windows 7 B) Linux C) Symbian D) Chrome OS Answer: b
Which of the following loads OS into memory during startup? A) Compiler B) BIOS C) Bootloader D) Kernel Answer: c
UNIX was originally developed by: A) Microsoft B) Bell Labs C) IBM D) Intel Answer: b
The first version of Windows was released in: A) 1981 B) 1985 C) 1989 D) 1992 Answer: b
Restarting the computer without turning off power is called: A) Hard boot B) Warm boot C) Power boot D) Soft shutdown Answer: b
The program that interprets commands is called: A) Kernel B) Shell C) Driver D) Disk manager Answer: b
Which of the following is not a function of OS? A) Memory management B) Process management C) File handling D) Weather forecasting Answer: d
The smallest unit of memory handled by OS is: A) Bit B) Byte C) KB D) File Answer: b
Mobile operating system among the following is: A) DOS B) Windows 98 C) Android D) Ubuntu Answer: c
GUI uses: A) Commands only B) Icons, windows & menus C) Text editors D) Numeric codes Answer: b
A running program is called: A) Command B) Process C) Thread D) Object Answer: b
Software that controls hardware is called: A) BIOS B) Driver C) Compiler D) Linker Answer: b
Which system allows multiple users at the same time? A) Single-user OS B) Multi-user OS C) Gate OS D) Multi-threaded OS Answer: b
The OS that guarantees immediate response is: A) Batch OS B) Real-Time OS C) Network OS D) Mobile OS Answer: b
The OS divides work into time slices in: A) Batch OS B) Time-sharing OS C) Multiprocessing OS D) Embedded OS Answer: b
Windows Server is an example of: A) Network OS B) Mobile OS C) Desktop OS D) Real-time OS Answer: a
Linux is written in: A) C language B) Java C) Python D) Assembly only Answer: a
The OS used in ATM machines is usually: A) Batch OS B) Real-time OS C) Distributed OS D) Multiuser OS Answer: b
Which OS uses terminal or shell commands? A) Windows 11 B) Linux / Unix C) Android D) macOS Answer: b
Chrome OS is developed by: A) Google B) Microsoft C) Apple D) IBM Answer: a
The main memory managed by OS is: A) ROM B) RAM C) Hard disk D) CD-ROM Answer: b
A user interacts with OS using: A) Shell B) ALU C) BIOS D) Compiler Answer: a
Firmware is stored in: A) ROM B) RAM C) CPU D) HDD Answer: a
Which OS is most used in mobile phones globally? A) iOS B) Android C) BlackBerry D) Symbian Answer: b
The master control program is also called: A) Driver B) Operating System C) BIOS D) Task manager Answer: b
Which OS supports multitasking? A) Windows B) Linux C) macOS D) All of the above Answer: d
Which type of OS is used to control embedded devices? A) Mobile OS B) Real-time OS C) Distributed OS D) Batch OS Answer: b
The OS responsible for protecting data and passwords: A) Security management B) Virus scanner C) File manager D) Hardware controller Answer: a
An interface where user types commands is: A) GUI B) CLI C) VDU D) Menu OS Answer: b
Which OS function allocates CPU time? A) Synchronization B) Scheduling C) Formatting D) Listing Answer: b
Programs required for computer startup are stored in: A) RAM B) ROM C) Hard disk D) Pen drive Answer: b
Which company developed Windows OS? A) Microsoft B) Google C) Apple D) IBM Answer: a
Which OS is used in iPads? A) Android B) iPadOS C) Symbian D) Windows mobile Answer: b
Which OS is most widely used on personal computers? A) UNIX B) Windows C) Android D) DOS Answer: b
Which is an example of a network operating system? A) Windows 10 B) Windows Server C) iOS D) Android Answer: b
Another name for restart is: A) Shutdown B) Warm boot C) Cold boot D) BIOS clear Answer: b
Which OS uses icons & menus for interaction? A) CLI B) GUI C) BIOS D) Scheduler Answer: b
The OS manages which resources? A) CPU B) Memory C) Input / Output devices D) All of the above Answer: d
📌 Process Management & Scheduling
A running program is called: A) Thread B) Process C) Job D) Task Answer: b
A process in the ready state means: A) It is waiting for I/O B) It is executing currently C) It is waiting to be assigned CPU D) It is completed Answer: c
Scheduling is done by the: A) Compiler B) Scheduler C) Hard Disk D) Loader Answer: b
The first process scheduling algorithm is: A) RR B) FCFS C) SJF D) Priority Answer: b
SJF stands for: A) Small Job First B) Shortest Job First C) Simple Job Format D) Scheduled Job First Answer: b
The scheduling method used in time-sharing systems is: A) FCFS B) Round Robin C) SJF D) LIFO Answer: b
In Round Robin scheduling, each process gets: A) Long time slice B) Infinite time slice C) Fixed time quantum D) No time slice Answer: c
Which scheduling is preemptive? A) FCFS B) SJF (non-preemptive) C) Round Robin D) FIFO Answer: c
Priority scheduling selects process with: A) Lowest priority B) Highest priority C) Random order D) Longest job Answer: b
Context switching means: A) Switching between memory blocks B) Swapping processes C) Switching CPU focus from one process to another D) Changing OS Answer: c
A process waiting for another resource is: A) Running B) Ready C) Blocked D) Terminated Answer: c
Terminated state means: A) Aborted B) Completed C) Killed D) All of these Answer: d
Foreground processes run: A) In background B) With user interaction C) Without scheduler D) Independently Answer: b
Background process is also called: A) Daemon B) Thread C) Kernel D) BIOS Answer: a
Critical section in OS refers to: A) Memory area B) Code accessing shared resource C) Unused space D) System hardware Answer: b
Mutual exclusion prevents: A) Context switching B) Memory fragmentation C) Race condition D) Multi-processing Answer: c
Race condition occurs when: A) Too many commands run B) Processes share resources incorrectly C) CPU overheats D) Disk crashes Answer: b
Deadlock condition means: A) CPU failure B) Processes waiting forever C) System restart D) Virus attack Answer: b
Which is not a condition for deadlock? A) Mutual exclusion B) Hold and wait C) Circular wait D) Fast switching Answer: d
Deadlock prevention means: A) Kill system B) Avoid one of deadlock conditions C) Reduce memory D) Increase CPU speed Answer: b
Banker’s algorithm is used for: A) Booting B) Deadlock avoidance C) Process creation D) Paging Answer: b
Longest Job First scheduling: A) Runs shortest job first B) Runs based on priority C) Runs longest job first D) Uses no queue Answer: c
Dispatcher function: A) Allocates memory B) Transfers control of CPU to process C) Handles interrupt D) Deletes process Answer: b
Process Control Block (PCB) stores: A) Data B) Process information C) Only ID D) File permissions Answer: b
Process ID is: A) Device name B) Unique number to identify process C) A kernel D) Task mode Answer: b
Multiple processes running at same time is: A) Single tasking B) Multitasking C) No scheduling D) Swapping Answer: b
Multiple CPUs working together is called: A) Multithreading B) Multiprocessing C) Multitasking D) Uniprocessing Answer: b
Multiple threads inside one process is: A) Booting B) Multithreading C) Multiprocessing D) Swapping Answer: b
Suspended state means: A) On hold temporarily B) Terminated C) Executing D) Ready Answer: a
Which causes deadlock? A) Multiple I/O B) Circular waiting C) Fast scheduling D) GUI mode Answer: b
Starvation means: A) Deadlock always B) Process waits indefinitely C) CPU failure D) No process running Answer: b
Which scheduling reduces starvation? A) SJF B) FCFS C) Aging D) RTS Answer: c
Round Robin is suitable for: A) Real-time systems B) Interactive systems C) Batch system D) Banking system Answer: b
Gantt chart is used for: A) CPU measurement B) Scheduling visualization C) Page replacement D) Cache handling Answer: b
Dispatcher latency means time required to: A) Print B) Switch process C) Boot OS D) Transfer data Answer: b
The first state of new process is: A) Ready B) New C) Running D) Blocked Answer: b
Fork() system call is used for: A) Delete task B) Create new process C) Enter critical section D) Add memory Answer: b
Process suspension reason: A) I/O wait B) High priority job arrival C) System load D) All Answer: d
Dispatcher handles: A) CPU switching B) Memory segmentation C) File management D) Encryption Answer: a
CPU utilization means: A) Percentage of time CPU is busy B) RAM speed C) Disk usage D) Memory availability Answer: a
Process creation is done using: A) Init() B) fork() C) create() D) load() Answer: b
A short job gets higher priority in: A) FCFS B) LJF C) SJF D) Priority Answer: c
Multiprogramming increases: A) Execution time B) CPU utilization C) RAM corruption D) Boot time Answer: b
Batch system does not need: A) User interaction B) Scheduling C) CPU D) Memory Answer: a
Interrupt means: A) Signal to CPU for attention B) End process C) Boot D) Load OS Answer: a
Which command interrupts execution? A) Ctrl + X B) Ctrl + C C) Ctrl + V D) Ctrl + S Answer: b
Process scheduling improves: A) CPU usage B) Boot time C) GUI capability D) Device speed Answer: a
Process holds resource while waiting for others: A) Resource allocation B) Hold & wait C) Free state D) Paging Answer: b
Deadlock detection means: A) Kill OS B) Identify cycle C) Reboot system D) Optimize CPU Answer: b
Recovering from deadlock by killing processes is: A) Deadlock avoidance B) Deadlock recovery C) Deadlock prevention D) Scheduling Answer: b
Which memory is volatile? A) ROM B) RAM C) SSD D) Hard Disk Answer: b
Which memory is permanent? A) RAM B) Cache C) ROM D) Registers Answer: c
Fastest memory is: A) HDD B) RAM C) Cache D) Pen Drive Answer: c
Virtual memory is: A) Secondary memory B) Using disk as RAM C) Backup memory D) Flash memory Answer: b
Paging divides memory into: A) Segments B) Frames / Pages C) Blocks D) Chunks Answer: b
Segmentation divides memory based on: A) Fixed size B) Logical divisions like code/data/stack C) Equal blocks D) ROM Answer: b
Thrashing occurs when: A) Too many interrupts B) Excessive paging/swapping C) Too many files D) Booting problem Answer: b
Swapping means: A) Copying files B) Moving processes between RAM and disk C) Formatting D) Renaming Answer: b
Fragmentation occurs when: A) Memory is not fully used B) Memory is overflow C) Memory is swapped D) Data lost Answer: a
Internal fragmentation means: A) Blocks unused outside memory B) Unused space inside allocated block C) No RAM available D) Cache full Answer: b
External fragmentation means: A) Too many processes B) Free spaces scattered C) No disk space D) Corruption Answer: b
Compaction reduces: A) Internal fragmentation B) External fragmentation C) Both D) None Answer: b
First-Fit algorithm allocates: A) Smallest free block B) First free block found C) Largest free block D) Best free block Answer: b
Best-Fit algorithm allocates: A) Largest block B) Best smallest fitting free block C) Random block D) Joint block Answer: b
Worst-Fit algorithm allows: A) Smallest block B) Largest block C) Mid block D) No block Answer: b
Page table contains: A) File names B) Mapping of virtual to physical addresses C) Cache addresses D) Interrupt numbers Answer: b
TLB stands for: A) Time Local Buffer B) Translation Lookaside Buffer C) Table Lookup Buffer D) Transfer Level Buffer Answer: b
TLB improves: A) I/O speed B) Page translation speed C) Boot speed D) Keyboard input Answer: b
Memory Management Unit (MMU) handles: A) CPU operations B) Address translation C) File naming D) Load balancing Answer: b
Page fault occurs when: A) Disk crashes B) Page is not in RAM C) CPU overheats D) Program ends Answer: b
Page replacement algorithm decides: A) Which page to remove from RAM B) File storage C) Device control D) Scheduling Answer: a
LRU stands for: A) Last Released Unit B) Least Recently Used C) Last Recently Updated D) Logical Resource Utility Answer: b
FIFO page replacement removes: A) First page loaded B) Last page loaded C) Max memory block D) Random page Answer: a
Optimal page replacement algorithm: A) Removes last used page B) Removes page not needed in future C) Removes smallest page D) Removes faulty page Answer: b
Demand paging means: A) Load pages only when required B) Load full program C) Load from ROM D) Load by user manually Answer: a
Dirty bit indicates: A) File deleted B) Page modified after loading C) Page corrupted D) Page swapped Answer: b
Cache memory stores: A) Frequently used instructions B) Temporary files C) Booting commands D) Deleted files Answer: a
Cache hit means: A) Data found in cache B) Data lost C) Memory corruption D) Page fault Answer: a
Cache miss means: A) No extra RAM B) Data not found in cache C) Slow CPU D) Interrupt Answer: b
Locality of reference refers to: A) Memory location repeatedly accessed B) Memory divided C) Memory loss D) Disk swapping Answer: a
Which memory stores BIOS? A) RAM B) ROM C) HDD D) Cache Answer: b
Main memory is also called: A) ROM B) Secondary memory C) Primary memory D) Logical memory Answer: c
Disk storage is: A) Primary memory B) Secondary memory C) Cache memory D) Virtual memory Answer: b
Memory hierarchy means: A) CPU flow B) Fast to slow memory arrangement C) IO system D) Buffer control Answer: b
Overlay technique is used for: A) Loading multiple programs B) Running large programs in limited memory C) Painting screen D) Delete processes Answer: b
Buddy system is: A) Memory allocation system B) File naming C) Cache synchronization D) Deadlock breaking Answer: a
DMA stands for: A) Direct Memory Address B) Direct Memory Access C) Data Memory Activity D) Dynamic Memory Allocation Answer: b
Swapping reduces: A) CPU time B) Load on RAM C) Cache D) Disk space Answer: b
Registers are: A) Slow memory B) Fastest memory in CPU C) Secondary memory D) Backup memory Answer: b
Which one is NOT secondary memory? A) HDD B) CD C) SSD D) RAM Answer: d
Spooling uses: A) Buffer memory B) Kernel memory C) Cache only D) ROM only Answer: a
Segmentation fault means: A) Accessing restricted memory B) No ROM C) No CPU D) Disk full Answer: a
Copy-on-write allows: A) Write lock B) Page sharing until modified C) Page corruption D) Dirty bit removal Answer: b
Belady’s anomaly occurs in: A) Paging B) FIFO page replacement C) Segmentation D) Scheduling Answer: b
Swapping files stored in: A) RAM B) Disk C) BIOS D) Cache Answer: b
Main goal of memory management: A) Reduce CPU speed B) Efficient use of RAM C) Increase hardware cost D) Encrypt data Answer: b
Frame means: A) Physical memory block B) Virtual address C) Cache mapping D) Boot sector Answer: a
Heap memory used for: A) Static allocation B) Dynamic allocation C) Booting D) Kernel Answer: b
Stack memory used for: A) Function calls & variables B) Long term storage C) Application data D) Kernel mapping Answer: a
RAM full effect: A) Faster computer B) Page faults increase C) Cache increase D) Disk erase Answer: b
A file is: A) Collection of records B) Collection of data stored in memory C) Hardware device D) A CPU program Answer: b
A directory is: A) File extension B) Folder that stores files C) Filename D) Keyboard key Answer: b
File extension of executable file in Windows: A) .txt B) .exe C) .docx D) .ppt Answer: b
Which one is NOT a file organization method? A) Sequential B) Indexed C) Direct D) Optional Answer: d
File allocation table is used in: A) FAT system B) Database C) Antivirus D) BIOS Answer: a
NTFS stands for: A) Network Table File System B) New Technology File System C) New Terminal Format System D) National Transfer File System Answer: b
Spooling stands for: A) System polling B) Simultaneous Peripheral Operation Online C) Serial print online D) Special online operation Answer: b
Spooling is mainly used for: A) Scanner B) Printer C) Audio system D) Monitor Answer: b
A device driver is: A) Hardware component B) Software controlling hardware C) Data file D) System shell Answer: b
File system manages: A) CPU scheduling B) Storage of files on disk C) RAM allocation D) Encryption Answer: b
Which command lists files in DOS? A) SHOW B) DIR C) LIST D) FILES Answer: b
Command to delete a file in DOS: A) DELETE B) REMOVE C) DEL D) ERASE Answer: c
Command to change directory: A) CD B) MD C) RD D) DIR Answer: a
Which command creates a new directory? A) CD B) MD C) NEWW D) COPY Answer: b
File attributes include: A) Read-only B) Hidden C) System file D) All of them Answer: d
Root directory means: A) Last directory B) Highest level directory C) Copy of directory D) Deleted folder Answer: b
Path determines: A) File location B) File name C) RAM size D) Booting type Answer: a
Absolute path starts from: A) Desktop B) Root directory C) Downloads D) Folder Answer: b
Relative path starts from: A) Home directory B) Root C) OS level D) BIOS Answer: a
File control block (FCB) stores: A) File size, permissions, location B) Boot data C) BIOS info D) Cache data Answer: a
Sequential file access means: A) Random access B) Access in order C) Tree access D) Infinite looping Answer: b
Random access used in: A) Disk files B) Tape files C) Printer D) BIOS Answer: a
Disk scheduling algorithm: A) SSTF B) FIFO C) LIFO D) SJF Answer: a
Device controller is: A) Hardware component for managing devices B) Part of database C) Application component D) Encryption tool Answer: a
Device queue stores: A) Waiting processes B) Waiting I/O requests C) File blocks D) Passwords Answer: b
I/O bound process spends most time in: A) CPU B) I/O operations C) Memory D) Scheduler Answer: b
Disk fragmentation occurs due to: A) Virus B) File deletion and storage gaps C) RAM clearing D) BIOS reset Answer: b
Defragmentation means: A) Delete files B) Arrange disk blocks sequentially C) Reduce memory D) Shut down system Answer: b
Disk scheduling improves: A) Disk throughput B) CPU speed C) Boot speed D) GUI look Answer: a
RAID stands for: A) Random Access Input Drive B) Redundant Array of Independent Disks C) Remote Access Internet Disk D) Real-time Array Integrated Device Answer: b
Read/write head is part of: A) CPU B) Hard disk C) RAM D) BIOS chip Answer: b
File access permission NOT included: A) Read B) Write C) Execute D) Print Answer: d
System call for file creation: A) create() B) newFile() C) del() D) sys() Answer: a
Tree structure directories are used in: A) Windows B) Linux C) UNIX D) All of the above Answer: d
I/O interrupt means: A) Program stopped B) Device asking for service C) Disk deleted D) CPU off Answer: b
Buffering helps in: A) Speeding I/O operations B) Shutting system C) Booting D) Installing software Answer: a
Caching is used to: A) Reduce CPU heat B) Speed repeated access C) Store deleted files D) Format disk Answer: b
UNC path is used in: A) Wireless B) Network shared directories C) App installation D) BIOS Answer: b
The smallest storage unit in disk: A) Track B) Sector C) Block D) Cluster Answer: b
File locking prevents: A) Multiple access conflict B) Power failure C) Disk crash D) Cache overflow Answer: a
Mounting means: A) Loading file in RAM B) Attaching storage device to directory tree C) Copying files D) Booting Answer: b
Unmounting means: A) Remove disk from directory tree B) Delete drive C) Shutdown D) Restart Answer: a
Tape storage supports: A) Sequential access B) Random access C) Combined methods D) Flash memory Answer: a
Hard disk supports: A) Only sequential access B) Only random access C) Both D) None Answer: c
File rename system call: A) rn() B) rename() C) mv() D) Both b & c Answer: d
Unmounted file system means: A) Files accessible B) Files not accessible C) System removed D) Boot mode Answer: b
Disk formatting means: A) Place disk blocks in order B) Erase all data and prepare for new storage C) Backup files D) Index creation Answer: b
Double buffering used in: A) Printing B) Graphics & gaming C) Database query D) Networking Answer: b
File deletion frees: A) Cache B) Disk blocks C) RAM D) BIOS Answer: b
I/O management goal: A) CPU scheduling B) Reduce device access time C) Increase keyboard speed D) Remove memory faults Answer: b
Operating system designed for real-time applications is called: A) Time-sharing OS B) Real-Time OS C) Distributed OS D) Batch OS Answer: b
Batch operating system works: A) With real-time response B) Without user interaction C) With GUI interface D) Only on mobile Answer: b
Unix is an example of: A) Single-user OS B) Multi-user OS C) Real-time OS D) Mobile OS Answer: b
Distributed operating system means: A) OS runs on single machine only B) Runs across multiple connected computers C) Runs mobile apps D) Runs BIOS Answer: b
Multiprocessing OS uses: A) Single CPU B) Multiple CPUs C) No CPU D) Only secondary memory Answer: b
Mobile operating systems include: A) Android, iOS B) Windows, Linux C) Solaris, Unix D) Fedora, DOS Answer: a
Time-sharing OS supports: A) One user B) Many users simultaneously C) Offline access D) Real-time systems Answer: b
Multi-tasking system means: A) One task at a time B) Multiple tasks at same time C) One job per day D) No scheduling Answer: b
Deadlock means: A) CPU locks B) Processes wait forever C) RAM destroyed D) Disk failure Answer: b
Kernel is: A) Command interpreter B) Core of OS C) Anti-virus D) Printer software Answer: b
Shell is: A) Graphical display B) User command interface C) Memory manager D) BIOS driver Answer: b
Monolithic kernel: A) Small kernel design B) Everything runs in kernel mode C) No scheduling D) No memory allocation Answer: b
Microkernel: A) Large kernel B) Moves most functions to user space C) Supports no threads D) Cloud computing only Answer: b
Hybrid kernel is used in: A) Linux B) Windows & macOS C) Android D) DOS Answer: b
Booting means: A) Shutting down B) Starting computer C) Format disk D) Install OS Answer: b
Cold boot means: A) Restart system B) Power ON start C) Sleep mode D) Sub-boot Answer: b
Warm boot means: A) Power ON B) Restart computer C) Shut system D) Format Answer: b
RTOS used in: A) Gaming B) Flight control systems C) Normal browsing D) Word processing Answer: b
Firmware is stored in: A) RAM B) ROM C) Disk D) USB Answer: b
BIOS stands for: A) Basic Information Output System B) Basic Input Output System C) Binary Internal OS D) Basic Internal Operation Software Answer: b
Bootloader loads: A) BIOS B) OS into memory C) Printer drivers D) USB software Answer: b
Cloud-based OS example: A) Chrome OS B) MS-DOS C) Windows XP D) Unix Shell Answer: a
Linux is based on: A) Apple kernel B) Windows kernel C) UNIX principles D) Android Software Answer: c
Command line OS example: A) Windows 11 B) MS-DOS C) Android D) macOS Answer: b
Example of distributed system: A) Google Cloud B) MS-DOS C) Windows 95 D) iPhone OS Answer: a
ATM machines mostly use: A) Batch OS B) RTOS C) Multiuser OS D) GUI OS Answer: b
UNIX creator: A) Bill Gates B) Linus Torvalds C) Ken Thompson & Dennis Ritchie D) Steve Jobs Answer: c
Linux creator: A) Linus Torvalds B) Dennis Ritchie C) IBM D) Microsoft Answer: a
Which OS is mostly used for servers? A) Windows 10 B) Linux / Unix C) Android D) macOS Answer: b
Virtual machine allows: A) Running RAM only B) Running multiple OS on single hardware C) Running without OS D) Running BIOS only Answer: b
Middleware used in: A) I/O devices B) Distributed systems C) RAM D) Internet only Answer: b
Cybersecurity in OS includes: A) Passwords B) Firewalls C) File permissions D) All of the above Answer: d
Firewall protects from: A) Hardware failure B) Unauthorized network access C) Disk corruption D) Bootloader Answer: b
Encryption means: A) Data compress B) Scrambling data to secure C) System restore D) Removing virus Answer: b
Access control list (ACL) used for: A) Memory allocation B) File permissions C) Booting D) Paging Answer: b
Example of mobile-embedded OS: A) Android B) Windows XP C) UNIX D) Solaris Answer: a
Cluster computing means: A) No network B) Multiple computers working as one C) Always offline D) No scheduling Answer: b
Grid computing used for: A) Gaming B) Scientific problem solving C) Movies only D) BIOS Answer: b
Peer-to-peer OS architecture used in: A) Torrent systems B) Mobile calling C) BIOS D) DOS Answer: a
Command interpreter role: A) Executes user commands B) Manage drivers C) Print files D) Make network Answer: a
Interrupt means: A) Virus infection B) Hardware signal requesting CPU attention C) Data deleted D) Disk formatting Answer: b
System call provides: A) Hardware to user B) Interface between OS & applications C) BIOS to CPU D) Firewall function Answer: b
Embedded OS example: A) Windows 10 B) VxWorks C) Linux Mint D) macOS Catalina Answer: b
Which OS features guarantee response time? A) Batch OS B) RTOS C) Distributed OS D) Cloud OS Answer: b
Multithreading improves: A) File storage B) Concurrent processing inside a process C) Disk formatting D) System errors Answer: b
System monitor in OS used for: A) Memory & CPU tracking B) Game control C) BIOS update D) Formatting Answer: a
OS handling multiple apps means: A) Multiuser B) Multitasking C) Multithreading D) Multiprocessor Answer: b
OS responsible for: A) Resource allocation B) Device control C) Protection & file system D) All of the above Answer: d
Cloud OS advantage: A) Local storage only B) Anywhere remote access C) No internet needed D) No security Answer: b
RTOS example: A) QNX B) Windows XP C) UNIX D) Chrome OS Answer: a
