100 questions and answers related to Operating System (OS) software

1. What is an Operating System?

   • An OS is system software that manages computer hardware and software resources and provides common services for computer programs.

2. Name some common Operating Systems.

   • Windows, macOS, Linux, Unix, Android, iOS.

3. What are the main functions of an OS?

   • Process management, memory management, file system management, device management, security, and user interface.

4. What are the types of Operating Systems?

   • Batch OS, Time-sharing OS, Distributed OS, Network OS, Real-time OS, Mobile OS.

5. What is a Kernel?

   • The kernel is the core part of an OS that controls system operations, hardware, and resources.

6. What are the two types of Kernels?

   • Monolithic Kernel and Microkernel.

7. What is a Shell in an OS?

   • A shell is a command-line interface that interacts with the OS kernel.

8. What is the difference between GUI and CLI?

   • GUI (Graphical User Interface) uses graphical elements, while CLI (Command Line Interface) uses text commands.

9. What is a Multi-user OS?

   • An OS that allows multiple users to access the system resources simultaneously, like Unix and Windows Server.

10. What is a Multi-tasking OS?

• An OS that allows running multiple applications at the same time, like Windows and Linux.

Process Management

11. What is a Process in an OS?

• A process is a program in execution, including its code, data, and resources.

12. What are the states of a Process?

• New, Ready, Running, Waiting, Terminated.

13. What is Process Scheduling?

• The method an OS uses to determine which process runs at a given time.

14. What are the types of Process Scheduling?

• Long-term, Short-term, and Medium-term scheduling.

15. What is a Scheduler?

• A scheduler manages process execution by deciding which process gets CPU time.

16. What is a Context Switch?

• The process of switching the CPU from one process to another.

17. What is Inter-Process Communication (IPC)?

• A mechanism that allows processes to communicate with each other.

18. What is Thread in OS?

• A thread is the smallest unit of execution within a process.

19. What are the types of Threads?

• User-level Threads and Kernel-level Threads.

20. What is a Deadlock?

• A situation where two or more processes are unable to proceed because each is waiting for the other to release resources.

Memory Management

21. What is Memory Management in OS?

• The process of controlling and coordinating computer memory, including RAM and cache.

22. What is Virtual Memory?

• A memory management technique that creates an illusion of a larger RAM by using disk space.

23. What is Paging?

• A memory management scheme that eliminates fragmentation by dividing memory into fixed-size pages.

24. What is Segmentation?

• A memory management technique that divides memory into variable-sized segments.

25. What is Demand Paging?

• A process where pages are loaded into memory only when needed.

26. What is Thrashing?

• A condition where excessive paging reduces performance.

27. What is the role of the Memory Manager?

• It allocates and deallocates memory to processes efficiently.

28. What is a Page Fault?

• It occurs when a requested page is not found in memory and must be fetched from disk.

29. What is Swapping?

• Moving a process between main memory and disk to free up space.

30. What is Fragmentation in Memory Management?

• The inefficient use of memory due to free space being split into small, unusable blocks.

File System Management

31. What is a File System?

• A system that manages how data is stored and retrieved on a disk.

32. What are the types of File Systems?

• FAT32, NTFS, EXT4, HFS+.

33. What is a Directory?

• A logical structure that stores and organizes files.

34. What is a File Descriptor?

• A unique identifier for an open file.

35. What is Mounting in OS?

• Attaching a storage device to a directory structure.

Device Management

36. What is Device Management?

• The process of controlling and coordinating input/output devices.

37. What is a Device Driver?

• Software that allows the OS to interact with hardware.

Security & Protection

38. What is an OS Security?

• Protecting the OS from threats like malware, unauthorized access, and system failures.

39. What are Access Control Mechanisms?

• Techniques to restrict unauthorized access to data and resources.

40. What is Authentication in OS?

• The process of verifying user identity.

Advanced OS Concepts

41. What is a Distributed OS?

• An OS that manages multiple computers as a single system.

42. What is a Real-time OS?

• An OS designed to process data within a strict time limit.

43. What is a Network OS?

• An OS that supports networking functions like remote access and file sharing.

44. What is Load Balancing in OS?

• Distributing workloads across multiple resources to optimize performance.

Command Line Interface (CLI) Commands

45. What is the ‘ls’ command in Linux?

• It lists files and directories.

46. What does the ‘cd’ command do?

• Changes the directory.

47. What is the ‘pwd’ command?

• Prints the current working directory.

48. What is the ‘rm’ command?

• Removes files or directories.

49. What is the ‘chmod’ command?

• Changes file permissions.

50. What is the ‘cp’ command?

• Copies files and directories.

Windows OS Specific Questions

51. What is the Windows Registry?

• A database that stores system settings.

52. What is Task Manager in Windows?

• A tool for monitoring processes and system performance.

53. What is the difference between Sleep and Hibernate?

• Sleep mode saves data in RAM, Hibernate saves it on disk.

Linux OS Specific Questions

54. What is the root user in Linux?

• The superuser with full system access.

55. What is the difference between ‘apt’ and ‘yum’?

• ‘apt’ is used in Debian-based systems, ‘yum’ in RedHat-based systems.

Linux OS Specific Questions (Continued)

56. What is the purpose of the sudo command in Linux?

• It allows a user to execute commands with superuser privileges.

57. What is the difference between hard links and soft links in Linux?

• A hard link points directly to the file's inode, while a soft link (symbolic link) points to another file path.

58. What is the purpose of the grep command?

• It searches for a specific pattern in files.

59. What is the df command used for?

• It shows disk space usage of file systems.

60. What does the ps command do in Linux?

• It displays currently running processes.

61. What is the difference between kill and pkill commands?

• kill terminates a process using its PID, while pkill terminates a process using its name.

62. What is the tar command used for?

• It is used to archive and extract files.

63. What is the /etc/passwd file?

• It stores user account information.

64. What is the /etc/shadow file?

• It stores encrypted user passwords.

65. What is the crontab command used for?

• It schedules jobs to run at specific times.

Windows OS Specific Questions (Continued)

66. What is the function of the Windows Task Scheduler?

• It automates the execution of tasks at specified times.

67. What is the Windows Safe Mode?

• A diagnostic mode used to troubleshoot system problems.

68. What is the purpose of the chkdsk command?

• It checks and repairs disk errors.

69. What is the Windows Event Viewer?

• A tool that logs system events, errors, and warnings.

70. What is the difference between NTFS and FAT32 file systems?

• NTFS supports larger files and permissions, whereas FAT32 has size limitations and lacks security features.

71. What is the purpose of the ipconfig command?

• It displays network configuration details.

72. How do you access the Windows Registry?

• By running regedit in the command prompt.

73. What is the purpose of the msconfig tool?

• It manages startup programs and system configurations.

74. What does the sfc /scannow command do?

• It scans and repairs system files.

75. What is the purpose of the Windows Defender?

• It provides built-in antivirus protection.

Networking & OS

76. What is a Network Operating System (NOS)?

• An OS designed to manage network resources and services.

77. What is the difference between TCP and UDP?

• TCP is connection-oriented, while UDP is connectionless and faster.

78. What is an IP address?

• A unique identifier assigned to a device on a network.

79. What is DHCP?

• A protocol that assigns IP addresses dynamically.

80. What is DNS?

• A system that translates domain names into IP addresses.

81. What is a MAC address?

• A hardware address assigned to a network device.

82. What is the difference between IPv4 and IPv6?

• IPv4 uses a 32-bit address format, while IPv6 uses a 128-bit address format.

83. What is a Firewall in an OS?

• A security system that monitors and controls network traffic.

84. What is NAT (Network Address Translation)?

• A process that translates private IP addresses to public IP addresses.

85. What is a Proxy Server?

• A server that acts as an intermediary between a user and the internet.

Security & OS Protection

86. What is User Authentication?

• A security process to verify the identity of a user.

87. What is an Access Control List (ACL)?

• A list of permissions attached to an object that specifies who can access it.

88. What is the difference between Encryption and Hashing?

• Encryption converts data into a readable format using a key, while hashing is a one-way process for data integrity.

89. What is a Rootkit?

• A type of malware that hides its presence and provides unauthorized access to a system.

90. What is a Zero-Day Exploit?

• A security vulnerability that is exploited before a fix is available.

91. What is a Botnet?

• A network of compromised computers controlled by a hacker.

92. What is Two-Factor Authentication (2FA)?

• A security process requiring two forms of verification.

93. What is Ransomware?

• A type of malware that encrypts files and demands payment for decryption.

94. What is Phishing?

• A cyber-attack where attackers trick users into revealing sensitive information.

95. What is the difference between a Virus and a Worm?

• A virus needs a host file to spread, while a worm spreads independently.

96. What is Intrusion Detection System (IDS)?

• A system that monitors network traffic for suspicious activity.

97. What is an Intrusion Prevention System (IPS)?

• A system that actively blocks detected threats.

98. What is a Honeypot in cybersecurity?

• A decoy system designed to attract and analyze cyber threats.

99. What is a Digital Signature?

• An electronic signature used to verify the authenticity of a document.

100. What is Patch Management in an OS?

• The process of updating software to fix vulnerabilities and improve security.