Attempt all questions. Correct answers are highlighted in yellow.
1. Which of the following is not a major reason for building distributed systems?
a)Resource sharing
b)Computation speedup
c)Reliability
d)Simplicity
✓ Correct Answer
💡 Explanation:Distributed systems add significant architectural complexity; thus, simplicity is not a reason for building them.
2. When hardware is accessed by reading and writing to specific memory locations, then it is called:
a)Port-mapped I/O
b)Controlled-mapped I/O
c)Bus-mapped I/O
d)None of the mentioned
✓ Correct Answer
💡 Explanation:This describes Memory-mapped I/O, which is not listed in the given options, making 'None of the mentioned' the correct answer.
3. What type of kernel architecture does OS X have?
a)Monolithic kernel with modules
b)Micro kernel
c)Monolithic kernel
d)Hybrid kernel
✓ Correct Answer
💡 Explanation:OS X (macOS) uses a hybrid kernel architecture that combines features of both monolithic and microkernel designs.
4. To access the services of the operating system, the interface is provided by the:
a)Library
b)Assembly Instructions
c)System calls
✓ Correct Answer
d)API
💡 Explanation:System calls provide the interface between user programs and the operating system services, allowing programs to request OS services.
5. What is used to point to the base address of a page table in memory?
a)Page Register
b)Program counter
c)Stack pointer
d)Page table base register
✓ Correct Answer
💡 Explanation:The Page Table Base Register (PTBR) stores the base address of the page table in memory for address translation.
6. When does a test-and-set instruction get executed?
a)Periodically
b)After a particular process
c)Atomically
✓ Correct Answer
d)At the end of process
💡 Explanation:Test and set instruction executes atomically, meaning it completes as a single uninterruptible operation to ensure synchronization.
7. The code segment that misuses its environment is called a:
a)Internal thief
b)Trojan horse
✓ Correct Answer
c)Code staker
d)Virus
💡 Explanation:A Trojan horse is malicious code that appears legitimate but misuses its environment or privileges to perform unauthorized actions.
8. The signal operations of the semaphore basically work on the basic ______ system calls.
a)continue()
b)wakeup()
✓ Correct Answer
c)getup()
d)start
💡 Explanation:The semaphore signal operation uses the wakeup() system call to wake up a waiting process from the blocked state.
9. The request and release of resources are handled through:
a)Command line statements
b)Interrupts
c)System calls
✓ Correct Answer
d)Special programs
💡 Explanation:Resource requests and releases are handled through system calls, which provide the interface for processes to request OS services.
10. Which of the following is not a valid state of a thread?
a)Running
b)Parsing
✓ Correct Answer
c)Ready
d)Blocked
💡 Explanation:Parsing is not a thread state; valid thread states include Running, Ready, Blocked, and Terminated.
11. If there are n resources of same types and 3 processes A, B, and C each demanding resource instances 2, 4, 8 respectively. What will be the value of n for which deadlock will not occur?
a)10
b)11
c)13
d)12
✓ Correct Answer
💡 Explanation:For deadlock avoidance, n must be at least (2-1) + (4-1) + (8-1) + 1 = 12 resources to ensure at least one process can complete and release resources.
12. Which one of the following deadlock handling technique uses Banker's algorithm?
a)Deadlock prevention
b)Deadlock avoidance
✓ Correct Answer
c)Deadlock detection
d)Deadlock recovery
💡 Explanation:Banker's algorithm is used for deadlock avoidance by ensuring the system remains in a safe state before allocating resources to processes.
13. Which one of the following techniques relocates processes in memory so the holes create one contiguous hole in the memory?
a)Paging
b)Segmentation
c)Swapping
d)Compaction
✓ Correct Answer
💡 Explanation:Compaction is a memory management technique that relocates all free memory holes into one large contiguous block to reduce external fragmentation.
14. Which one of the following consists of variables and data structures along with the procedures for solving synchronization problem?
a)Semaphore
b)Critical section
c)Monitor
✓ Correct Answer
d)Mutex
💡 Explanation:A Monitor is a high-level synchronization construct that encapsulates shared variables, data structures, and procedures to solve synchronization problems in a structured way.
15. Which of the following is not a desirable feature in CPU scheduling?
a)Maximum throughput
b)Minimum throughput
✓ Correct Answer
c)Maximum CPU utilization
d)Minimum waiting time
💡 Explanation:Minimum throughput is undesirable as we want to maximize the number of processes completed per unit time for better system performance.
16. Identify the system for which FCFS algorithm is not suitable for CPU scheduling.
a)Batch processing system
b)Time sharing system
✓ Correct Answer
c)Real-time system
d)Embedded system
💡 Explanation:FCFS is not suitable for time-sharing systems because it doesn't provide fair CPU time distribution and can cause long waiting times for interactive processes.
17. CPU switching from one process to another requires saving the state of the current process and loading the latest state of the next process is called __________.
a)Process scheduling
b)Process management
c)Context switching
✓ Correct Answer
d)Process migration
💡 Explanation:Context switching is the mechanism where the CPU saves the current process state and loads the next process state to switch execution between processes.
18. Which of the following is not a requirement for the solution to the critical section problem?
a)Mutual exclusion
b)A process running outside the critical section may block other process to enter in critical section
✓ Correct Answer
c)Progress
d)Bounded waiting
💡 Explanation:This violates the progress requirement; processes outside the critical section should not prevent other processes from entering their critical section.
19. Identify the name of the process in which a page is copied in the main memory from the secondary memory on the basis of requirements.
a)Page replacement
b)Swapping
c)Demanding paging
✓ Correct Answer
d)Thrashing
💡 Explanation:Demand paging loads pages into main memory from secondary storage only when they are needed, improving memory efficiency and reducing initial load time.
20. What is the maximum length (number of characters) of the filename in DOS?
a)8
✓ Correct Answer
b)11
c)12
d)255
💡 Explanation:In MS-DOS (FAT filesystem), filenames follow the standard 8.3 format where the base filename can have a maximum of 8 characters.
21. Which process can be affected by other processes executing in the system?
a)Cooperating process
✓ Correct Answer
b)Init Process
c)Parent process
d)Child Process
💡 Explanation:Cooperating processes share resources and communicate with each other, making them susceptible to being affected by the actions of other executing processes.
22. What is compaction?
a)A technique for overcoming internal fragmentation
b)A technique for overcoming external fragmentation
✓ Correct Answer
c)A paging technique
d)A technique for overcoming fatal error
💡 Explanation:Compaction is specifically designed to overcome external fragmentation by relocating memory blocks to create one large contiguous free memory space.
23. The code segment that misuses its environment is called a:
a)Internal thief
b)Trojan horse
✓ Correct Answer
c)Code stacker
d)Virus
💡 Explanation:A Trojan horse is malicious code that appears legitimate but misuses its environment or privileges to perform unauthorized actions or compromise system security.
24. Which of the following file attribute defines the unique tag number within file system?
a)Identifier
✓ Correct Answer
b)Protection
c)Type
d)Size
💡 Explanation:The Identifier attribute (often called inode number or file ID) provides a unique tag number that uniquely identifies each file within the file system.
25. Which of the following is single user operating system?
a)MS-DOS
✓ Correct Answer
b)UNIX
c)Windows
d)MAC
💡 Explanation:MS-DOS (Microsoft Disk Operating System) is a single-user operating system designed to support one user at a time without multitasking capabilities.
26. In distributed system each processor has its own:
a)Local memory
b)Clock
c)Both local memory and clock
✓ Correct Answer
d)None of these
💡 Explanation:In distributed systems, each processor maintains its own local memory for storage and its own clock for timing, ensuring independent operation and coordination.
27. Why is one-time password safe?
a)It is easy to generate
b)It is different for every access
✓ Correct Answer
c)It cannot be shared
d)It is a complex encrypted password
💡 Explanation:One-time passwords (OTP) are safe because they generate a unique password for each access session, making them invalid after a single use and preventing replay attacks.
28. Which of the following is not a major reason for building distributed systems?
a)Resource sharing
b)Computation speedup
c)Reliability
d)Simplicity
✓ Correct Answer
💡 Explanation:Simplicity is not a reason for building distributed systems; distributed systems are inherently more complex than centralized systems due to coordination and communication overhead.
29. Which one of the following techniques relocates processes in memory so the holes create one contiguous hole in the memory?
a)Paging
b)Segmentation
c)Fragmentation
d)Compaction
✓ Correct Answer
💡 Explanation:Compaction is a memory management technique that relocates all processes to consolidate free memory holes into one large contiguous block, eliminating external fragmentation.
30. External fragmentation will not occur when?
a)First fit is used
b)Worst fit is used
c)Best fit is used
d)No matter which algorithm is used, it will always occur
✓ Correct Answer
💡 Explanation:External fragmentation occurs with all contiguous memory allocation algorithms (first fit, best fit, worst fit) because memory becomes divided into non-contiguous fragments over time.
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