UGC NET - File and I-O systems, security and protection mechanisms, cryptography basics, virtualization and virtual machines. Online Test (MCQ Quiz)

1. Which file system is commonly used in Unix-like operating systems and supports features like journaling and hard links?

A) FAT32 B) NTFS C) ext4 D) HFS+

2. What is the primary purpose of a journaling file system?

A) To improve data compression B) To reduce disk fragmentation C) To ensure file system consistency after a crash D) To increase file access speed

3. In the context of I/O systems, what does DMA stand for and what is its main advantage?

A) Direct Memory Access; allows CPU to directly access I/O devices B) Dynamic Memory Allocation; manages memory for I/O operations C) Direct Memory Access; allows I/O devices to transfer data directly to/from main memory without CPU intervention D) Data Input/Output Management; controls data flow between CPU and peripherals

4. Which I/O buffering technique involves using a separate memory area to hold data during transfer between a device and main memory?

A) Polling B) Interrupt-driven I/O C) Direct Memory Access (DMA) D) Spooling

5. What is the main goal of access control in operating systems?

A) To manage CPU scheduling B) To prevent unauthorized access to system resources C) To optimize memory allocation D) To handle inter-process communication

6. Which security mechanism uses a set of rules to determine what actions a user or process is allowed to perform on a file or resource?

A) Encryption B) Authentication C) Access Control Lists (ACLs) D) Firewall

7. What is the difference between authentication and authorization?

A) Authentication verifies identity; Authorization grants permissions. B) Authentication grants permissions; Authorization verifies identity. C) Authentication is for files; Authorization is for users. D) They are the same concept.

8. Which cryptographic technique involves transforming plaintext into ciphertext using a secret key?

A) Hashing B) Digital Signature C) Encryption D) Symmetric Key Cryptography

9. What is a key characteristic of symmetric encryption?

A) It uses two different keys: one for encryption and one for decryption. B) It is generally slower than asymmetric encryption for large amounts of data. C) It uses the same secret key for both encryption and decryption. D) It is primarily used for digital signatures.

10. Which of the following is an example of a hashing algorithm?

A) RSA B) AES C) MD5 D) Diffie-Hellman

11. What is the main purpose of a hash function in cryptography?

A) To encrypt messages securely B) To generate a unique fixed-size fingerprint of data C) To establish a secure communication channel D) To digitally sign documents

12. What is a virtual machine (VM)?

A) A physical computer with enhanced performance B) A software-based emulation of a physical computer system C) A type of operating system kernel D) A network protocol for data transfer

13. What is the role of a hypervisor?

A) To manage physical hardware resources B) To manage user accounts and permissions C) To create, run, and manage virtual machines D) To provide network connectivity to VMs

14. Which type of hypervisor runs directly on the host's hardware?

A) Type II (Hosted) B) Type I (Bare-metal) C) Software-based D) Emulated

15. What is a benefit of using virtualization?

A) Reduced hardware costs and better resource utilization B) Increased complexity in system management C) Slower performance for all applications D) Elimination of the need for operating systems

16. In the context of file systems, what is a 'symbolic link' (symlink)?

A) A direct pointer to the inode of a file B) A file that contains the data of another file C) A special file that points to another file or directory by name D) A backup copy of a file

17. What is the primary difference between a hard link and a symbolic link?

A) Hard links point to inodes; symbolic links point to file paths. B) Hard links can span across file systems; symbolic links cannot. C) Symbolic links are faster than hard links. D) Hard links are only for directories; symbolic links are only for files.

18. Which I/O control method involves the CPU constantly checking the status of an I/O device?

A) Interrupt-driven I/O B) Direct Memory Access (DMA) C) Memory-mapped I/O D) Programmed I/O (Polling)

19. What is the purpose of a 'spooler' in I/O systems?

A) To manage direct memory access transfers B) To buffer data for slow devices like printers C) To authenticate user requests D) To encrypt data before transmission

20. In security, what is a 'rootkit'?

A) A type of firewall software B) A piece of malware designed to gain unauthorized access and hide its presence C) An encryption algorithm D) A secure file system

21. What is the principle of 'least privilege' in security?

A) Granting users the maximum possible permissions B) Granting users only the minimum permissions necessary to perform their tasks C) Restricting access to only the root user D) Encrypting all data by default

22. Which cryptographic concept ensures that a message has not been tampered with during transit?

A) Confidentiality B) Integrity C) Availability D) Authentication

23. What is the primary use of asymmetric encryption (public-key cryptography)?

A) Fast encryption/decryption of large data volumes B) Secure key exchange and digital signatures C) Password storage D) Data compression

24. In the context of virtual machines, what is 'guest OS'?

A) The operating system that runs on the physical hardware B) The operating system running inside a virtual machine C) The hypervisor software D) The network operating system

25. What is 'virtualization overhead'?

A) The cost of purchasing virtual machine software B) The additional system resources consumed by the hypervisor and virtualization layer C) The time taken to boot a virtual machine D) The storage space required for virtual disk images

26. Which file system is native to Windows operating systems and supports features like file permissions, journaling, and encryption?

A) ext4 B) HFS+ C) NTFS D) ZFS

27. What is the 'inode' in Unix-like file systems?

A) A directory entry containing file name and inode number B) A data structure that stores metadata about a file, including its location and permissions C) A user account identifier D) A buffer for I/O operations

28. Which I/O method uses interrupts to signal the CPU when an I/O operation is complete?

A) Programmed I/O B) Interrupt-driven I/O C) Polling D) Direct Memory Access

29. What is a 'security domain' in the context of protection mechanisms?

A) A physical network segment B) A region of the system where a particular set of security policies is enforced C) A type of encryption key D) A user group

30. What is the purpose of a digital signature?

A) To encrypt data for confidentiality B) To verify the authenticity and integrity of a digital message or document C) To compress data for efficient storage D) To manage network access control

31. Which cryptographic algorithm is commonly used for secure key exchange?

A) AES B) MD5 C) Diffie-Hellman D) SHA-256

32. What is 'virtualization' in computing?

A) The process of creating physical hardware B) The creation of a virtual version of a computing resource, such as an operating system, server, storage device, or network C) The act of encrypting data D) The management of physical memory

33. In a Type II hypervisor (hosted), what component runs directly on the host hardware?

A) The guest operating system B) The virtual machine monitor (VMM) C) The host operating system D) The application software

34. What is the main advantage of using a virtual machine over a physical machine for testing purposes?

A) Higher performance B) Easier hardware upgrades C) Isolation and ability to revert to previous states D) Direct hardware access

35. What is a 'block device' in the context of I/O systems?

A) A device that transfers data character by character B) A device that transfers data in fixed-size blocks, such as a hard drive or SSD C) A network interface card D) A printer

36. Which file system feature allows multiple directory entries to point to the same file data?

A) Journaling B) Hard links C) Symbolic links D) Access Control Lists

37. What is the primary function of the 'mount' command in Unix-like systems regarding file systems?

A) To format a disk partition B) To detach a file system from the directory tree C) To attach a file system to a specific point in the directory tree D) To check for file system errors

38. What is a 'security vulnerability'?

A) A security policy enforced by the system B) A weakness in a system that could be exploited by a threat C) A method of encrypting data D) A user's authentication credentials

39. Which of the following is a cryptographic hash function known for its speed but now considered insecure due to collision vulnerabilities?

A) SHA-256 B) MD5 C) AES D) RSA

40. What is the purpose of a 'salt' in password hashing?

A) To make the hash function faster B) To add randomness to the password before hashing, protecting against rainbow table attacks C) To encrypt the password D) To store the password securely

41. In virtualization, what is 'snapshotting'?

A) The process of taking a picture of the VM's console B) Saving the current state of a virtual machine so it can be restored later C) Creating a backup of the VM's operating system D) Recording VM performance metrics

42. What is a 'virtual disk' in the context of virtualization?

A) A physical storage device B) A file that emulates a physical hard drive for a virtual machine C) A network storage location D) A memory allocation for a VM

43. Which file system was developed by Oracle and is known for its advanced features like data integrity, performance, and scalability, often used in enterprise environments?

A) NTFS B) ext4 C) ZFS D) Btrfs

44. What is 'thrashing' in the context of operating system memory management and I/O?

A) Excessive page swapping between main memory and secondary storage, leading to poor performance B) A security attack that overwhelms a system with requests C) A file system corruption error D) A high CPU utilization due to complex I/O operations

45. What is the primary goal of data encryption?

A) To increase data storage efficiency B) To ensure data confidentiality by making it unreadable to unauthorized parties C) To speed up data access D) To verify the integrity of data

46. What is a 'threat' in cybersecurity?

A) A weakness in a system B) An event or actor that has the potential to harm an asset C) A security policy D) An encryption key

47. Which type of I/O operation typically involves reading or writing data sequentially, such as accessing a tape drive?

A) Block I/O B) Character I/O C) Sequential Access I/O D) Random Access I/O

48. What is the main security benefit of using a Virtual Private Network (VPN) in conjunction with virtualization?

A) It prevents the hypervisor from being compromised. B) It encrypts network traffic between the VM and the network, enhancing security. C) It speeds up the boot time of virtual machines. D) It allows VMs to share physical hardware more efficiently.

49. Which cryptographic primitive is essential for ensuring non-repudiation, meaning a sender cannot deny having sent a message?

A) Symmetric Encryption B) Hashing C) Digital Signatures D) Random Number Generation

50. What is the concept of 'disk striping' in RAID (Redundant Array of Independent Disks) configurations?

A) Writing data redundantly across multiple disks for fault tolerance. B) Splitting data into blocks and writing these blocks across multiple disks to improve performance. C) Using parity information to reconstruct lost data. D) Mirroring data onto a secondary disk.

File and I-O systems, security and protection mechanisms, cryptography basics, virtualization and virtual machines. - Online Test

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