Unit – 1 Introduction to operating system
1. An operating system acts as an interface between:
a) User and software
b) User and hardware (CORRECT)
c) Software and hardware
d) None of the above
2. Which of the following is NOT a service provided by an operating system?
a) Process management
b) Memory management
c) Device management
d) Word processing (CORRECT)
3. The first operating systems were:
a) Batch processing systems (CORRECT)
b) Multitasking systems
c) Multiprogramming systems
d) Real-time systems
4. In a batch processing system, jobs are:
a) Submitted individually for immediate execution
b) Grouped together and executed sequentially (CORRECT)
c) Executed concurrently on multiple processors
d) None of the above
5. Multiprogramming allows:
a) Running only one program at a time
b) Running multiple programs concurrently in memory (CORRECT)
c) Sharing resources between multiple processors
d) None of the above
6. Multiprocessing involves:
a) A single CPU with multiple cores
b) Multiple CPUs sharing resources (CORRECT)
c) Running multiple programs sequentially
d) None of the above
7. Multitasking allows:
a) Running only one program at a time
b) Running multiple programs concurrently, but only one can be actively using the CPU at a time (CORRECT)
c) Sharing resources between multiple processors
d) None of the above
8. The layered structure of an operating system is designed for:
a) Increased complexity
b) Improved modularity and maintainability (CORRECT)
c) Reduced performance
d) None of the above
9. A process is an instance of a program in:
a) Compilation
b) Execution (CORRECT)
c) Development
d) Testing
10. A file is a collection of:
a) Processes
b) Hardware components (CORRECT)
c) System calls
d) Instructions
11. System calls are used by:
a) Hardware to communicate with the OS
b) User applications to access OS services (CORRECT)
c) The OS to manage hardware directly
d) None of the above
12. An interrupt is a signal from a:
a) User application to the OS
b) Hardware device to the OS (CORRECT)
c) The OS to a user application
d) None of the above
13. A shell is a:
a) Hardware component
b) User interface for interacting with the OS (CORRECT)
c) System program for managing files
d) Programming language
14. Unix is a:
a) Hardware brand
b) Programming language (CORRECT)
c) Word processing software
d) None of the above
15. Which shell command is used to display the current working directory?
a) ls (CORRECT)
b) pwd
c) cd
d) cat
16. The "cat" command is used to:
a) Display the contents of a file (CORRECT)
b) Copy a file
c) Move a file
d) Delete a file
17. The "cp" command is used to:
a) Display the contents of a file
b) Copy a file (CORRECT)
c) Move a file
d) Delete a file
18. The "mv" command is used to:
a) Display the contents of a file
b) Copy a file
c) Move a file (CORRECT)
d) Delete a file
19. The "rm" command is used to:
a) Display the contents of a file
b) Copy a file
c) Move a file
d) Delete a file (CORRECT)
20. The "man" command is used to:
a) Display the manual page for a command (CORRECT)
b) List all available commands
c) Change permissions of a file
d) Edit a file
Unit – 2 Process Management
1. An instance of a program in execution is called a:
a) Thread
b) Function
c) Process (CORRECT)
d) Module
2. The different states a process can be in are:
a) Running, waiting, terminated (CORRECT)
b) Open, closed, deleted
c) Active, inactive, paused
d) None of the above
3. A process transitions from running to waiting state when:
a) It finishes execution
b) It encounters an I/O operation (CORRECT)
c) It needs to be preempted by another process
d) All of the above
4. The Process Control Block (PCB) is a data structure that stores information about:
a) The user
b) The hardware (CORRECT)
c) The network
d) None of the above
5. The Process Context includes:
a) Program counter
b) CPU registers (CORRECT)
c) Stack pointer
d) All of the above
6. A context switch is the process of saving the context of one process and loading the context of another process onto the CPU.
a) True (CORRECT)
b) False
7. Which of the following is NOT a benefit of context switching?
a) Improved system responsiveness
b) Increased CPU utilization
c) Efficient handling of multiple processes (CORRECT)
d) Reduced memory usage
8. The scheduling algorithm determines the order in which processes are selected for execution by the CPU.
a) True (CORRECT)
b) False
9. Which of the following is NOT a common scheduling algorithm?
a) First-Come, First-Served (FCFS)
b) Shortest Job First (SJF)
c) Priority Scheduling
d) Round-Robin (RR) (CORRECT)
10. In FCFS scheduling, processes are executed in the order they arrive.
a) True (CORRECT)
b) False
11. SJF scheduling prioritizes processes with the shortest execution times.
a) True (CORRECT)
b) False
12. Priority scheduling assigns different priorities to processes, with higher priorities receiving better access to the CPU.
a) True (CORRECT)
b) False
13. Round-robin scheduling gives each process a quantum of CPU time, after which it is preempted and placed at the end of the ready queue.
a) True (CORRECT)
b) False
14. Deadlock occurs when a set of processes are blocked, waiting for resources held by each other.
a) True (CORRECT)
b) False
15. Which of the following is NOT a necessary condition for deadlock?
a) Mutual exclusion
b) Hold and wait
c. No preemption (CORRECT)
d. circular wait
16. Inter-process communication (IPC) allows processes to share data and synchronize their execution.
a) True (CORRECT)
b) False
17. Semaphores are a common type of synchronization primitive used to control access to shared resources.
a) True (CORRECT)
b) False
18. Multithreading allows a single process to have multiple threads of execution that can run concurrently.
a) True (CORRECT)
b) False
19. Threads within a process share the same memory space and resources.
a) True (CORRECT)
b) False
20. Context switching between threads is generally faster than context switching between processes.
a) True (CORRECT)
b) False
Unit – 3 Process Scheduling
1. Scheduling algorithms can be classified as:
a) Preemptive and non-preemptive (CORRECT)
b) Static and dynamic
c) User-defined and system-defined
d) High-level and low-level
2. In a preemptive scheduling algorithm, the CPU can be taken away from a running process.
a) True (CORRECT)
b) False
3. FCFS (First Come, First Served) is a:
a) Preemptive algorithm
b) Non-preemptive algorithm (CORRECT)
c) Priority-based algorithm
d) Time-quantum-based algorithm
4. SJF (Shortest Job First) prioritizes processes with:
a) Longest execution times
b) Shortest execution times (CORRECT)
c) Highest priority values
d) Equal priority
5. In priority scheduling, processes with higher priorities have:
a) Longer waiting times
b) Shorter waiting times (CORRECT)
c) No impact on waiting time
d) None of the above
6. Round-robin (RR) scheduling allocates CPU time in:
a) Fixed-size chunks
b) Variable-size chunks (CORRECT)
c) Priority-based manner
d) None of the above
7. CPU utilization refers to the percentage of time the CPU is busy.
a) True (CORRECT)
b) False
8. Throughput is the number of processes completed per unit of time.
a) True (CORRECT)
b) False
9. Turnaround time is the total time taken by a process to complete from its submission to its completion.
a) True (CORRECT)
b) False
10. Waiting time is the time a process spends waiting for the CPU.
a) True (CORRECT)
b) False
11. Response time is the time it takes for a process to start running after it submits a request for the CPU.
a) True (CORRECT)
b) False
12. Inter-process communication (IPC) allows processes to:
a) Share data and synchronize their execution (CORRECT)
b) Independently access resources
c) Communicate with the user
d) Terminate each other
13. A race condition occurs when the outcome of a program depends on the:
a) Specific order of instructions
b) Timing of events (CORRECT)
c) User input
d) Hardware configuration
14. A critical section is a part of a program where access to shared resources must be exclusive.
a) True (CORRECT)
b) False
15. Semaphores are used to:
a) Signal events between processes
b) Control access to shared resources (CORRECT)
c) Manage memory allocation
d) Schedule processes
16. Semaphores can be used to implement mutual exclusion, ensuring only one process can access a critical section at a time.
a) True (CORRECT)
b) False
17. Deadlock occurs when a set of processes are blocked, waiting for resources held by each other.
a) True (CORRECT)
b) False
18. Starvation occurs when a process is continuously denied access to resources and never finishes execution.
a) True (CORRECT)
b) False
19. Fairness in scheduling ensures that all processes have an equal chance of accessing the CPU.
a) True (CORRECT)
b) False
20. The choice of scheduling algorithm depends on various factors, including the system type, workload characteristics, and desired performance metrics.
a) True (CORRECT)
b) False
Unit – 4 Deadlock
1. Deadlock occurs when a set of processes are:
a) Running concurrently
b) Blocked, waiting for resources held by each other (CORRECT)
c) Sharing data efficiently
d) Terminating successfully
2. Which of the following is NOT a necessary condition for deadlock?
a) Mutual exclusion
b) Hold and wait
c. Preemption(CORRECT)
d. circular wait
3. Deadlock prevention aims to:
a) Allow deadlock to occur, but provide mechanisms for recovery
b) Prevent deadlock from occurring in the first place (CORRECT)
c) Improve the performance of individual processes
d) Optimize resource utilization
4. Deadlock avoidance uses information about future resource requests to:
a) Allocate resources safely
b) Detect deadlock situations (CORRECT)
c) Recover from deadlock
d) All of the above
5. The Banker's Algorithm is an example of a:
a) Deadlock prevention technique (CORRECT)
b) Deadlock detection technique
c) Deadlock recovery technique
d) None of the above
6. Deadlock detection involves:
a) Identifying processes that are in deadlock
b) Preventing deadlock from occurring (CORRECT)
c) Recovering from deadlock situations
d) All of the above
7. Deadlock recovery involves:
a) Identifying processes that are in deadlock
b) Preventing deadlock from occurring
c) Restoring the system to a safe state (CORRECT)
d) None of the above
8. Which of the following recovery techniques can be used to address deadlock?
a) Terminating one or more deadlocked processes
b) Rolling back the state of some processes
c) Preempting resources from deadlocked processes (CORRECT)
d) All of the above
9. Deadlock is a serious problem in operating systems because it can lead to:
a) Increased CPU utilization
b) Improved system responsiveness
c) System hangs and wasted resources (CORRECT)
d) Faster program execution
10. Which of the following is most likely to contribute to deadlock?
a) Single resource type with multiple processes
b) Abundant resources available
c) Short execution times for processes
d) Limited memory space
11. Deadlock prevention can be achieved by:
a) Allocating all resources to processes at the start
b) Denying resource requests that could lead to deadlock (CORRECT)
c) Allowing processes to share resources freely
d) None of the above
12. The Banker's Algorithm requires information about:
a) The number of CPU cycles each process needs
b) The current allocation and maximum claim of each process for each resource type (CORRECT)
c) The priority level of each process
d) The estimated I/O operations of each process
13. When deadlock detection is used, the system must maintain additional data structures to track resource allocation and process states.
a) True (CORRECT)
b) False
14. Deadlock recovery can be a complex and time-consuming process, potentially leading to data loss or service disruptions.
a) True (CORRECT)
b) False
15. Techniques to prevent deadlock often involve trade-offs with resource utilization and system performance.
a) True (CORRECT)
b) False
16. Deadlock is more likely to occur in systems with:
a) Few resource types and many processes
b) Many resource types and few processes
c) Abundant resources and short execution times
d) Limited resources and long execution times (CORRECT)
17. Deadlock can be avoided by ensuring that at least one necessary condition for deadlock is not met.
a) True (CORRECT)
b) False
18. Deadlock detection and recovery should be used as a last resort, as they are resource-intensive and can impact system performance.
a) True (CORRECT)
b) False
19. Understanding deadlock and its prevention/detection/recovery techniques is crucial for designing reliable and efficient operating systems.
a) True (CORRECT)
b) False
20. Deadlock is a significant concern in distributed systems due to the complex interactions and communication between processes.
a) True (CORRECT)
b) False
Unit – 5 Memory Management
1. Memory management is the process of:
a) Allocating and managing physical memory for programs and data (CORRECT)
b) Optimizing CPU utilization
c) Handling user input and output
d) Providing security for the system
2. Contiguous allocation assigns a continuous block of memory to each process.
a) True (CORRECT)
b) False
3. Fixed-partitioning divides memory into fixed-size partitions of equal size.
a) True (CORRECT)
b) False
4. Dynamic partitioning allocates memory to processes in variable-sized chunks as needed.
a) True (CORRECT)
b) False
5. Non-contiguous allocation allows a process to be scattered across multiple non-continuous blocks of memory.
a) True (CORRECT)
b) False
6. Paging divides the physical memory and logical address space into fixed-size blocks called frames and pages, respectively.
a) True (CORRECT)
b) False
7. Segmentation divides the logical address space into variable-sized segments, each representing a logical unit of memory (e.g., code, data).
a) True (CORRECT)
b) False
8. Virtual memory creates the illusion of a larger address space than physically available using a combination of RAM and secondary storage (e.g., hard disk).
a) True (CORRECT)
b) False
9. Demand paging loads pages into memory only when they are referenced by the process, improving memory efficiency.
a) True (CORRECT)
b) False
10. Copy-on-write (COW) optimizes memory usage by delaying the creation of separate copies of memory pages shared by multiple processes until one process attempts to modify the page.
a) True (CORRECT)
b) False
11. Page replacement algorithms determine which page should be removed from memory when a new page needs to be loaded and no free frame is available.
a) True (CORRECT)
b) False
12. Common page replacement algorithms include FIFO (First-In, First-Out), LRU (Least Recently Used), and Optimal.
a) True (CORRECT)
b) False
13. The frame allocation policy determines how free frames are assigned to processes requesting new pages.
a) True (CORRECT)
b) False
14. Thrashing occurs when a process constantly faults pages in and out of memory due to excessive page faults, leading to poor performance.
a) True (CORRECT)
b) False
15. Techniques to prevent thrashing include reducing the working set size of processes, increasing the number of available frames, and modifying the page replacement algorithm.
a) True (CORRECT)
b) False
16. External fragmentation occurs when free memory is scattered across multiple small chunks, making it useless for larger processes.
a) True (CORRECT)
b) False
17. Internal fragmentation occurs within a memory partition when there is enough free space to hold a process, but the space is not contiguous.
a) True (CORRECT)
b) False
18. Memory management plays a crucial role in ensuring efficient utilization of memory resources, preventing fragmentation, and providing virtual memory for processes.
a) True (CORRECT)
b) False
19. Understanding different memory management techniques is essential for designing and implementing efficient operating systems.
a) True (CORRECT)
b) False
20. The choice of memory management technique depends on factors such as the system type, workload characteristics, and desired performance goals.
a) True (CORRECT)
b) False
Unit – 6 Files and protection
1. A file system is a system for: a) Managing files and directories (CORRECT) b) Executing programs c) Communicating with devices d) Handling user input
2. File system design considers factors such as: a) File naming conventions b) Storage allocation methods c) Access control mechanisms (CORRECT) d) All of the above
3. Sequential access allows reading or writing data one unit after another in a specific order. a) True (CORRECT) b) False
4. Direct access allows accessing any data unit (e.g., record) by directly calculating its location using its index. a) True (CORRECT) b) False
5. Swapping is the temporary transfer of data between main memory and secondary storage (e.g., hard disk) to make space for active processes. a) True (CORRECT) b) False
6. Contiguous allocation stores a file in a single, continuous block of memory. a) True (CORRECT) b) False
7. Linked allocation allocates file data into blocks scattered across the storage device, linked by pointers in each block. a) True (CORRECT) b) False
8. Indexed allocation uses an index table that maps logical file blocks to physical storage blocks. a) True (CORRECT) b) False
9. Authentication verifies the identity of a user attempting to access the system. a) True (CORRECT) b) False
10. Access control determines who can access resources and what operations they are allowed to perform. a) True (CORRECT) b) False
11. Access rights specify the specific permissions granted to users or groups for accessing resources (e.g., read, write, execute). a) True (CORRECT) b) False
12. System logs record system events, user activities, and security-related information for auditing and troubleshooting purposes. a) True (CORRECT) b) False
13. Protection mechanisms aim to safeguard resources from unauthorized access, modification, or destruction. a) True (CORRECT) b) False
14. Common security threats include unauthorized access, data breaches, malware attacks, and denial-of-service attacks. a) True (CORRECT) b) False
15. Passwords are a common authentication method, requiring users to provide a secret key or phrase for verification. a) True (CORRECT) b) False
16. Multi-factor authentication (MFA) utilizes two or more independent verification factors to enhance security. a) True (CORRECT) b) False
17. Access control lists (ACLs) explicitly define access rights for individual users or groups for specific resources. a) True (CORRECT) b) False
18. Capabilities are tokens issued to users that grant them specific rights to access resources, reducing the risk of unauthorized access. a) True (CORRECT) b) False
19. Encryption scrambles data into an unreadable format using a key, protecting confidentiality from unauthorized parties. a) True (CORRECT) b) False
20. Regularly updating software and applying security patches are essential steps in maintaining a secure system. a) True (CORRECT) b) False
