BCA – III

Operating System
(Paper-III)

1. Introduction: Definition, Early Systems, Simple Batch system, Multi programmed Batch. Time Sharing Systems, Personal Computer System, Parallel Systems, Distributed Systems, Real-time Systems.

Q-1) Discuss the role of operating System as a resource manager and also discuss the evolution of operating systems. (20)

Ans Hint> O.S. as resource manager :

Q-2) Discuss the features of Time Sharing, Multi Programmed, Batch processing and distributed operating systems. (20)

Q-3) What are the three main purpose of an Operating system? What are the main advantages of multiprogramming? (20)

Q-4) Differentiate between:
(i) Soft and Hard real time systems. (10)
(ii) Parallel and distributed systems. (10)

Q-5) An operating system controls and co-ordinates the use of computer resources among different users. Explain. (10)

Q-6) Differentiate between the following
(i) Single user and multi user operating system.(10)
(ii) Real time and Time Sharing Operating System. (10)
(iii) FCFS and Round Robin (10)

Q-7) List various types of operating systems. Discuss in detail the concept of real time systems. Name a few real time systems. (20)

Q-8) What is an Operating System? Mention at least six heads under which, the various functions of an operating system can be classified and explain their role. (15)

Q-9) Give various types of Operating Systems. (5)

Q-10) Trace the brief history and development of various operating systems. (10)

Q-11) List different types of operating system available, based on how they handle data processing jobs and users. (10)

Q-12) What are the three major areas in which the operating system divides its services? Give examples. (10)

Q-13) What do you mean by Operating System and the importance of an Operating System? (10)

Q-14) Explain Time Sharing and Real Time System. (10)

Q-15) What do you mean by an Operating System? Explain the different types of operating system available, based on how they handle data processing jobs and users. (20)

Q-16) Describe action of the Kernel when processes make system calls for the following purposes:
(a) A receive request for a message.
(b) A Memory Request.
(c) Request to create a process.
(d) Request to terminate a child process. (20)

2. Processes: Process concepts, Process Scheduling, threads.

Q-1) What are the major process scheduling techniques? Discuss their merits and also compare their waiting time and turn around time by taking an example. (20)

Q-2) What is meant by ready, running and blocked state of process? Discuss the role of Process Control Block. (20)

Q-3) What are the different states of a process? Discuss the transition of a process from running to blocked and blocked to ready state. (20)

Q-4) Give queuing diagram representation of process scheduling. Also discuss the role of short term, medium term and long term schedulers. (20)

Q-5) Explain in detail the concept of process scheduling and different scheduling queues. (20)

Q-6) Distinguish among a process, program and thread. (10)

Q-7) Distinguish between a program and process, explaining why the use of the process concept is necessary in studying operating systems. (10)

Q-8) What is process scheduling? (10)

Q-9) In some situations, a change in the state of one process may cause a change in the state of another process. Explain all such situations. (20)

Q-10) What do you mean by process scheduling? Explain Priority based scheduling. (10)

3. CPU-Scheduling: Basic concepts, scheduling criteria, scheduling algorithms, algorithm evaluation.

Q-1) Give queuing diagram representation of process scheduling. Also discuss the role of short term, medium term and long term schedulers. (20)

Q-2) What is the difference between preemptive and non-preemptive scheduling? (10)

Q-3) Explain FCFS, SJF and multilevel queue scheduling algorithms. (10)

Q-4) What is CPU- I/O burst cycle? What are different CPU scheduling criteria? Explain the role of CPU scheduler and dispatcher in CPU scheduling (15)

Q-5) Differentiate between FCFS and Round Robin scheduling. (5)

Q-6) Following is the information relating to some processes:

Process Burst Priority Arrival Time
P1 21 1 0
P2 13 5 6
P3 10 3 8
P4 8 1 10
P5 6 6 13

Using the above information, compute the average waiting time and average turn around time for each process for the following algorithms
(a) Preemptive SJF
(b) Priority Scheduling
(c) Preemptive Priority Scheduling
(d) Round Robin (with time quantum of 3 units)
Note: Ignore the arrival time for non-preemptive algorithms. (20)

Q-7) What do mean by CPU scheduling? What is scheduling criteria? Discuss in detail. (20)

Q-8) List and explain the major types of CPU scheduling. (10)

Q-9) Distinguish between preemptive and non- preemptive scheduling policies. (10)

Q-10) Explain scheduling and various techniques of Scheduling. (10)

4. Process Synchronization: Background critical – section, problem, semaphores, classical problem of synchronization.

Q-1) Write short note on
(i) Semaphores (ii) Thrashing (20)

Q-2) What is meant by critical section problem? How can semaphores be used for process synchronization? Explain. (20)

Q-3) What is Semaphore? Define P & V Operations on semaphores. Also explain Bounded-Buffer problem. (20)

Q-4) What are the three requirements that a solution to the critical section problem must satisfy? Also explain Bounded-Buffer problem. (20)

Q-5) Define Semaphores. In which cases are used? Explain how these can be implemented? (20)

Q-6) What are the three requirements that a solution to the critical section problem must satisfy? (5)

Q-7) What are semaphores? How do they implement mutual exclusion? What are the different types of semaphores? How can they be implemented? (20)

Q-8) What is critical section problem? (10)

Q-9) Describe how semaphores can be used for block/wakeup synchronization between processes. (10)

Q-10) What is classical problem of synchronization? (10)

Q-11) What do you mean by Semaphores and Semaphores used in concurrent system?

5. Memory Management: Background, Logical v/s Physical address space, swapping, continuous allocation, paging, segmentation.

Q-1) What is meant by fragmentation problem? How can it be controlled using Paging and Segmentation technique? Explain. (20)

Q-2) Describe the First Fit, Best Fit and Worst fit techniques of memory allocation and compare them with paging technique. (20)

Q-3) Write short note on the following:
(i) Fragmentation
(ii) Segmentation technique of memory management. (20)

Q-4) Differentiate between:
(i) Page and Segment (10)
(ii) Swapping and Compaction (10)

Q-5) Explain the following algorithms
(1) First-Fit (2) Best-Fit (3) Worst-Fit (20)

Q-6) When do page fault occurs? Describe the action taken by operating system when a page fault occurs. Also explain the causes of thrashing. (20)

Q-7) What is paging? How is it implemented? What is the difference between paging and segmentation? (20)

Q-8) Discuss in detail the segmentation scheme of memory management? Compare it with paging scheme. (15)

Q-9) Is it necessary for all of the pages of a process to be in main memory while the process is executing? (5)

Q-10) In a paging system, which of the following actions are likely to improve CPU utilization and which would reduce it? Account for your answer.
(i) Increase CPU speed.
(ii) Increase paging disk speed
(iii) Increase the number of active processes.
(iv) Reduce the number of active processes. (20)

Q-11) Distinguish between paging and segmentation. Why is paging faster than segmentation?

Q-12) Is it necessary for all the pages of a process to be in main memory while the process is executing? (10)

Q-13) On a simple paged system can the logical address space be larger than the physical address space? Can it be smaller? Explain. (10)

Q-14) Name and explain different memory management schemes. (10)

Q-15) Discuss impact of page size on the overall system performance. (5-10)

Q-16) Describe the general objectives of the memory management system within an operating system. (15)

Q-17) Why is relocation of program in memory necessary? (5)

Q-18) Explain the address translation mechanism in paging. Why is the page size normally some power of two? (10)

Q-19) Explain Static and Dynamic memory allocation. (10)

6. Virtual Memory: Background, demand paging, performance of demand paging, page replacement, page replacement algorithms, allocation of frames, threshing.

Q-1 Discuss the demands paging technique of memory management and also discuss the FIFO and optimal page replacement algorithms. (20)

Q-2 What is meant by page replacement? Discuss the different algorithms used for page replacement. (20)

Q-3) Explain the following page replacement algorithms:
(a) LRU (b) Optimal replacement (c) FIFO (15)

Q-4) Write a note on thrashing. (10)

Q-5) Why do systems that use demand paging generally deliver higher performance than those that use virtual memory? (10)

Q-6) Compare various page replacement algorithms/strategies. (10)

Q-7) How does virtual memory system prevent programs from accessing each other’s data? (10)

Q-8) What is Thrashing? When does it occur? How can one avoid it? (10)

7. Secondary Storage Structures: Disk structures, Disk scheduling, Disk Reliability.

Q-1 How an operating system carries out the disk scheduling? Compare the SSTF and SCAN scheduling algorithm. (20)

Q-2 Discuss the disk structure and describe the different disk scheduling algorithms. (20)

Q-3) Write a note on Disk Reliability? How can it be maintained? (20)

Q-4) How SCAN, C-SCAN and LOOK disk scheduling algorithms differ in their approach? (15)

Q-5) What is Disk structure? (5)

Q-6) Discuss in detail the structure of floppy disk. (20)

Q-7) What do you understand by disk scheduling and disk reliability? Explain. (10)

Q-8) Explain the Disk scheduling. (10)

8. Deadlocks: System Model, Deadlock characterization, methods for handing deadlocks, Deadlocks Prevention, Deadlock avoidance, Deadlock detection, Recovery from deadlock, combined approach to deadlock handling.

Q-1 Define the deadlock situation. How can a deadlock situation be prevented and avoided? Explain (20)

Q-2 Define the deadlock. How can it be prevented? (10)

Q-3) What is safe state? Explain Banker’s algorithm of Deadlock Avoidance. (20)

Q-4) What do you mean by a deadlock? Discuss various deadlock detection and recovery techniques in brief. (20)

Q-5) What is Deadlock? Give an Example. (10)

Q-6) Explain how deadlock can be represented graphically for two processes and two resources. (10)

Q-7) Name different strategies that operating system designers can adopt Vis-à-vis problem of a deadlock. (10)

Q-8) What is Deadlock? Explain how a deadlock can be detected and what are the different approaches to recover from deadlocks? (20)

Q-9) Explain Deadlock and deadlock avoidance (10)

Other Questions:

Q-1) Write short note on: (20)
a) Virtual Memory
b) Threads
c) Distributed System
d) Demand Paging

Q-2) Explain following: (20)
a) Deadlock
b) Deadlock Prevention
c) Memory Fragmentation.
d) Multiprogramming.