PESIT SOUTHCAMPUS
Faculty:Sudhakar
No. Of Hours:52 Question Bank
UNIT 1: INTRODUCTION TO OPERATING SYSTEMS & THEIR CLASSIFICATION Objective: The main objective of this chapter is to study the Operating system basics & Classifications.
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Give the features of symmetric and asymmetric multiprocessing system. Explain the concept of virtual machines. With a neat sketch explain the working of a virtual machine.(Dec-12)
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10* i. Real time system ii) Multiprocessor system What is the purpose of command interpreter? Why is it usually separate from the Kernel? 6* Explain the different view points that are used to understand the role of an operating system. june/july 13 What is operating system? What are functions of operating system? 6* What are multiprocessor systems? Give advantages. 6 What is the main difficulty that a programmer must overcome in writing an operating 6 system for real time environment? Define Operating system. Discuss it’s role with user and system viewpoint. .(Dec6* Explain the distinguishing features of
9. 12) 10. Explain the following terms and their working with diagram a. Spooling c) Time sharing d) Distributed system e) Real-time 11. Why dual mode operation in operating system is required? june/july 134 12. Compare tightly coupled systems with loosely coupled systems. 6* 13. Explain graceful degradation and fault tolerance in a multiprocessor system. 14. Describe differences between symmetric and asymmetric multiprocessing. What are three advantages and one disadvantage of multiprocessor systems? 15. Explain distinguished features of i) Time-sharing system ii) Parallel processing 16. Write a brief note on different operating system structures
Buffering b) 6x5*
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17. Explain different sub components of an operating system. 18. Bring out the requirements of i. Real time operating systems (ii) Distributed operating systems 19. What is an Operating System? Justify the statement “Operating System can be viewed as a government, resource allocator and a control program”. List the OS responsibilities in connection, with a process management and 20. memory management. (DEC 2011)
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What is the main advantage for an operating-system designer of using a virtual21.
machine architecture? What is the main advantage for a user? 22.
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Define essential properties of the following types of Operating system: Batch operating system ii) Interactive operating system i) iii) Time sharing operating system iv) Real time operating system v. Distributed operating system Distinguish among the following terminologies associated with the operating system and explain each of them in detail. i) Multiprogramming systems. ii) Multitasking systems. (iii) Multiprocessor systems.
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The main functions of an OS are: i.) Process Management ii.) Memory Management iii.) Input/ Output Manag
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25.
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iv.) Storage/ File system management 1 27. When a computer is first turned on or started , a special type of absolute loader called ________________ i. Compile and go loader ii) boot loader iii) bootstrap loader iv) relating loader The operating system manages i. emory ii) processes ii) Disk and the I/O devices iv) all of the above
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UNIT 1: OPERATING SYSTEM STRUCTURES Objective: The Operating System provides certain services to programs and to the users of those programs in order to make their tasks easier. The services differ from the operating system to another, but we identify and explore some common classes of these services. 1. List out services provided by the Operating Systems? 4* 2. What are client server systems & Peer-to-Peer systems? 5 3. What is the purpose of the system calls & system programs? 5* 4. Explain the layered approach of the operating system 5 5. Write short notes on operating system components. 5* 6. What is the purpose of command interpreter? Why is it usually separate from kernel? 6 What is the main difficulty that a programmer must overcome in writing an operating system 6 7. for real time environment? 6* 8. Define spooling and the need for it. Explain its working with necessary diagrams. 9.
What is the meaning of overlapped CPU and I/O operation? Explain.
10.Distinguish between : i) Process and Program ii) Multiprogramming and multiprocessing 11. What are system calls? Explain different categories of system calls?
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12. What are the five major activities of an operating system in regard to file management 13. What are the five major activities of an operating system in regard to process management?
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14. What are the three major activities of an operating system in regard memory management
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15. What are the three major activities of an operating system in regard to secondary storage management 16. Explain the functions of the following: i. System Calls ii) System programs iii) Command Interpreter
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17.What is virtual machine? Explain the just-in-time (JIT) compiler, used in java virtual machine. (DEC 2011) 18. Explain the layered approach to the structuring of an operating system along with the relevant diagram 19. List out and explain briefly the various services that the operating system provides to programs and users 20.Briefly explain the common classes of services provided by the various Operating systems for helping the user and for ensuring the efficient operation of the system. 21. Explain the different system components of an operating system. 22.Briefly explain the clustered systems and real time systems (Dec-12) 23.What is virtual machine? Explain the just-in-time (JIT) compiler, used in java virtual machine.
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24.Explain the salient feature of i) distributed operating system ii) real time operating system. june/july 13
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25.List out and explain briefly the various services that the operating system provides to programs and users
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Which is not the function of the Operating System? 26.
i. Memory management ii. Disk management iii. Application management iv. Virus Protection
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27.Throughput in case of multiprogramming is________.
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28.Multiprogramming degenerates to _________________________ system if there is no proper mix of CPU and I/O bound jobs.
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29.A ____________________________ operating system is an operating system which requires a timely response from a computer system. 30.An OS is the interface between _________ & __________. Suppose the architecture of a computer system is layered into the following four layers 1. Operating systems software users’ applications software 2. 3. hardware 4. programming environment software 31. Which of the following is a logical sequence of the four layers from bottom to top? a. 1, 2, 3, 4 b. 1, 3, 4, 2 c. 3, 1, 4, 2 UNIT 2: PROCESS, INTER PROCESS COMMUNICATION, THREADS & SCHEDULING
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Objective: This Chapter will give details of how OS is responsible for Creation and deletion of both users And system processes, the scheduling of processes, providing mechanisms for synchronization communication and deadlock handling for processes. Also you can study how to improve both utilization of CPU and speed of computer's Response for the users, different scheduling algorithms. 1. What are different differences between user level threads & Kernel supported threads? 2. What is Scheduler? What is a dispatcher? 6 3. Give the information that is kept in process control block 4. What are threads? 5. Differentiate between long term and short term scheduler. 6. Explain the hard real time system. (DEC2011) 7. What is co-operating process? 8. Write short note on CPU scheduling criteria. 9. Explain different types of CPU Schedulers. 10.Differentiate the following with examples i. Preemptive and non preemptive scheduling ii) I/O bound and CPU bound iii)Scheduler and dispatcher 11.Differentiate Pre-emptive and Non-preemptive scheduling giving the application of each of them 12.What is the criterion used to select the time quantum in case of round-robin scheduling algorithm? Explain it with a suitable example. 13.Explain multilevel feedback queue scheduling with example. 14.Differentiate between a process and a program. Describe the life cycle of a process 15.What is a process? What is a state diagram, explain states of a process. Also write the structure of a process control block.( Dec-12) 16.Write short note on algorithm evaluation 17. Describe the process states with the help of process transition diagram (DEC 2011)
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PESIT SOUTHCAMPUS 18.Explain the concept of „process‟. also describe the contents of a process control block(PCB) 19.What resources are used when a thread is created? How do they differ from those used when a process is created? 20.Define the actions taken by a kernel to context switch: a. among threads b. among processes 21.With illustration explain how processes are created and executed in an operating system (june / july 13) 22.What are co-operating processes? Describe the mechanism of inter process communication using shared memory in a producer-consumer problem 23.What is co-operating process? Explain. 24.What is interprocess communication? Explain 25.Explain the benefits of multithreaded programming. (DEC 2011) 26.Discuss the three common ways of establishing relationship between user and kernel threads (Dec 12) 27.Explain process states with a diagram. What is the need for a context switch? 28.Explain the role of long term scheduler, medium term scheduler and short tem scheduler in O.S 29.Explain the PCB in detail 30.Explain how process are created and terminated. 31.Discuss the different types of schedulers, giving the advantage and limitation of each. 32.Describe interprocess communication with regard to direct communication and indirect communication. 33.For the following set of process find the average waiting time using Gantt chart for i> SJF ii> Priority scheduling process Burst time Priority p1 5 5 p2 3 4 p3 8 3 p4 2 1 p5 1 2 The process has arrived in the order p2, p1, p4, p3 and p5.
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34.What is the difference between a preemptive and non-preemptive scheduling algorithms? Explain FCFS scheduling algorithm. Find the average turnaround time and average waiting time for the processes given in the table below. Process CPU burst time(in ms) P1 24 P2 3 P3 3
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35.Consider the following data with burst time given in milliseconds: i> SJF ii> Priority scheduling process Burst time Priority p1 10 3 p2 1 1 p3 2 3 p4 1 4 p5 5 2 The process has arrived in the order p1, p2, p3, p4, p5 all at time 0. a. Draw Gantt charts for the execution of these processes using FCFS, SJF, a nonpreemptive priority and RR (quantum=1) scheduling. b. What is the turnaround time and waiting time of each process for each of the scheduling algorithm.
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36.What 2 advantages do threads have over multiple processes? What major disadvantages do they have? Suggest one application that would benefit from the use of threads.
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PESIT SOUTHCAMPUS 37.What do you mean by process and process state? Give the state diagram corresponding to process states and explain 38. Suppose the following jobs arrive for processing at the times indicated, each job will run the listed amount of time. Job arrival time burst time 1 0.0 8 2 0.4 4 3 1.0 1 i) Give a Gantt chart illustrating the execution of these jobs using the non preemptive FCFS and SJF scheduling algorithms. ii) what is turn around time and wait time of each job for the above algorithms? iii) compute average turn around time if the CPU is left idle for the first 1 unit and then SJF scheduling is used.(job q and job 2 will wait during this time)` 39.Consider the following set of processes with their arrival and burst times as shown Process A.T B.T P0 0 10HR P1 0 05HR P2 1 02HR P3 2 01HR Compute the turn around time and waiting time of each job using the following scheduling algorithms. i. FCFS ii) S.J.F iii) Round-Robin ( choose time quantum=1) 40.For the following set of processes, find the average waiting time & average turn around time using GANTT Chart for I > FCA II> SJF preemptive. III> SJF non-preemptive. Process Arrival time (in sec) Burst Time(in sec) P1 0 4 P2 1 2 P3 2 5 P4 3 4
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41.What are threads ? how do they differ from a process? Explain the difference in process level switching and thread level switching 42.Distinguish between symmetric and asymmetric communication between processes. 43.Define CPU utilization, throughput, turnaround time, waiting time and response time
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44.Explain the different types of scheduling algorithms. 45.Five batch jobs A,B,C,D and E arrive at a computer centre at almost at the same time. They have estimated running times of 10,6,2,4 and 8 minutes. Their priorities are 3,5,2,1 and 4 respectively, with 5 being the highest priority. For each of the following scheduling algorithm determine the turn around time of each process and waiting time of each process. Ignore process switching overhead. Mention which algorithm results in minimal average waiting time. i) Round Robin ii) Priority scheduling iii) First come first served iv) Shortest job first. For case i) assume that system is multiprocessing and each job gets its fair share of the CPU.(time quantum 2 minutes). For cases (ii),(iii) and (iv) assume that only one job runs at a time, until it finishes. All jobs are completely CPU bound. 46.Define CPU utilization, throughput, turnaround time, waiting time and response time
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47.
Explain the different types of scheduling algorithms
48. An optimal scheduling algorithm in terms of minimizing the average waiting time of a given set of processes is ________. 1 FCFS scheduling algorithm 2 Round robin scheduling algorithm 3 Shorest job - first scheduling algorithm 4 None of the above
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In Priority Scheduling a priority number (integer) is associated with each process. The CPU is allocated to the process with the highest priority (smallest integer = highest priority). The problem is Starvation of low priority processes which may never execute, is resolved by __________. 1 Terminating the process. 2 Aging 3 Mutual Exclusion 4 Semaphore 50.
Which of the following is a criterion to evaluate a scheduling algorithm? 1 CPU Utilization: Keep CPU utilization as high as possible. 2 Throughput: number of processes completed per unit time. 3 Waiting Time: Amount of time spent ready to run but not running. 4 All of the above 51.
With the round robin CPU scheduling in a time-shared system ________. 1 Using very large time slice degenerates in to first come first served algorithm 2 Using extremely small time slices improve performance 3 Using extremely small time slices degenerate in to last in first out algorithm 4 Using medium sized time slices leads to shortest request time first algorithm
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Given the following processes and burst times Process Burst Time P1 13 P2 5 P3 23 P4 3 P5 31 P6 3 P7 14 Calculate the average wait time when each of the below scheduling algorithms is used? ? Non Pre-Emptive, First Come, First Serve ? Round Robin ? Shortest Job First Assume that a quantum of 6 is being used. 53. What is a scheduler? Illustrate any two types of scheduling using GANTT chart 10 54. How can Round Robin be made to mimic FCFS scheduling algorithm? 55.The context of a process is the union of it’s ______ . a. region tables, u area, system level context b. register context, pregion tables, user level context c. system-level context, register context, user-level context d. process table, user-level context, register context 56. Which of the following is NOT a part of a process control block : a. Values of CPU registers P E S Institute of Tech., Bangalore South Campus – Education for the Real World – Course Information – BE. V-Sem
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PESIT SOUTHCAMPUS UNIT 3 & 4: PROCESS SYNCRHONISATION AND DEADLOCKS Objective: Upon completion of this chapter you will be able to define how data consistency is maintained, Study of Semaphores, use and its implementation, Classical problems of synchronization, Deadlock and methods for handling deadlocks. 1. What is critical section? What requirement should be satisfied for a solution to the critical section problem? 4* 2. What are classical problems of synchronization? 4* 3. Explain the terms critical section and mutual exclusion. 4* 4. Write a note on „safe state‟ 4 5. Explain starvation. Differentiate deadlock and starvation. 4 Explain the terms critical section and mutual exclusion 5* 6. 7* What is semaphore? Explain how it can be used to solve the producer – consumer problem (Dec 12) 7. 5* 8. What are semaphores? Explain how it can be used to implement mutual exclusion 5* 9. Define resource allocation graph with an example and show how it can be used for dead lock 5* link detection 5* 10. What are monitors? Explain. 11. Explain the critical section problem 12. Define Test and Set instruction and implement mutual exclusion, using test and set. (DEC 2011) 13. Explain the readers/writers problem 6 14. What are the three requirements to be met by a solution to the critical section problem? 6*
Explain. 15. What are the necessary conditions for deadlock to occur? 16. Explain the resource allocation graph 17.What is the term busy waiting? What other kinds of waiting are there in an OS? Can busy waiting be avoided altogether? Explain. 18. Suggest the methods for deadlock recovery 19. What is a semaphore and a counting semaphore? Explain how a semaphore can be used so that statement S1 of process P1 is always executed first, and only then statement S2 of process P2 is executed. 20. What is a deadlock? Explain how resource allocation graph can be used to check for deadlock in a system. 21. Write an algorithm to implement critical section problem for multiple processes 22.What is critical section problem? Explain the requirements to satisfied by any solution to critical section problem. (June/july 13) 4* 23. Explain the synchronizing protocol of a classical readers/writers problem. Write a symbolic program code to implement any one of the above protocol. 24. What are called as co-operating processes? Explain the necessity of mutual exclusion with an example. 25. Explain the methods for deadlock prevention 26. What is a semaphore? Explain the role of semaphore in solving mutual exclusion problem 27. Given 3 processes A,B and C, three resources x,y and z and following events, i) A requests x ii) A requests y iii) B requests y iv) B requests z v) C requests z vi) C requests x vii) C requests y Assume that requested resources should always be allocated to the request process if it is available. Draw the resource allocation graph for the sequences. And also mention whether it is a deadlock? If it is, how to recover the deadlock. 28. the deadlock avoidance algorithm 29. Lists any 4 examples of deadlock that are not related to the computer systems. (DEC2011)
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PESIT SOUTHCAMPUS 30. State Dining Philosopher‟s problem and give a solution for the same, using semaphores. Write the structure for philosopher i. 31. What is deadlock? Explain the necessary conditions for its occurrence. 32. Give a scheme for detecting and recovering deadlock 33. What is critical section problem? Write a solution to n process critical section problem. 34. Define deadlock. List and elaborate the necessary condition for deadlock to occur. 35.Explain the safety algorithm used in Banker’s algorithm, with suitable data structures. (DEC2011) 36.Sleeping-barber and sleeping-customers problem: A barber shop consists of a waiting room with N chairs (chair[1],chair[2],….chair[N]) and the barber room containing the barber chair (chair[0]). If there are no customers to be served, the barber goes to sleep. If a customer enters the shop and all the chairs are occupied, then the new customer goes to sleep. If the barber is busy, but the waiting chairs are available, then the new customer occupies the next free chair to maintain the queue. If the barber is asleep, the customer wakes up the barber and occupies the barber chair. Assume chair[0] in one of the critical sections and all waiting chairs are another critical section. Also assume only one of the following abstract functions are available: i> Haircut(); //barber busy in his work ii> Customers-shift-to-next-chair() //after haircut customer gets up from barber chair and all other customers shift by one position to the next chair towards the barber chair. iii> Customer-occupies-free-chair() // new customer occupies the next free chair or if no customers are waiting then directly occupies the barber chair. Write an abstract C-program to coordinate the barber and customers in this problem, using semaphores with atomic operations wait() and signal(). Assume suitable data structures for abstract implementation. (DEC2011) 37. With regard to process synchronisation describe what is meant by race conditions?5 38. Describe an approach of mutual exclusion that does not require busy waiting. 10
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39. Explain how Banker’s algorithm is used in deadlock avoidance with an example.
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40.Banker’s algorithm is an example of ___________________ avoidance. 41.Mutex is a ______________________Semaphore.
42. What is critical section problem and what are the requirements that need to be satisfied by any solution to critical section problem? Give a solution to a 2 process critical section problem. 43. Write and explain Banker‟s algorithm for deadlock avoidance 44. What is critical section problem? Give a software solution to critical section problem in multiple processes. 45. What is the difference between deadlock prevention and deadlock avoidance methods of dealing with a dead lock problem? Explain the different approaches towards a dead lock detection problem when i) there is a single instance of a resource type ii) Multiple instances of a resource type 46. Write and explain deadlock detection algorithm and explain how it differs from Banker‟s algorithm. 47. What is deadlock? Explain the various methods for dealing with deadlock problem 48. Mention any hardware machine instruction you know of which can be used to implement the „wait-s‟ function for binary semaphore –S. Demonstrate how the specific instruction could be used to implement the desired function. State the disadvantages of the above method and
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49. Explain banker‟s algorithm using the example given below A system has 5 processes, p1,p2,p3,p4 and p5.There are 3 types of resources r1,r2 and r3.there are 10 instances of r1, 5 instances of r2 and 7 instances of r3. At time t0, the situation is as follows; Process allocation of maximum requirement of r1 r2 r3 r1 r2 r3 P1 0 1 0 7 5 3 P2 2 0 0 3 2 2 P3 3 0 2 9 0 2 P4 2 1 1 2 2 2 P5 0 0 2 4 3 3 Is the system in a safe state at time t0? Suppose now a time t1, process p2 requests one additional instance of resource type r1 and 2 instances of resource type r3, supposing the request if granted will the system be in a safe state? 50.Explain necessary and sufficient conditions for deadlock to occur. (Dec-12) 51. Consider the following snapshot of a system Process allocation Max
Available A B C D 1 5 2 0
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A B C D
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P1 P2 P3 P4
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Answer the following questions using Bankers Algorithm 1.What is the content of array need 2.Is the system in a safe state ?? 3.If a request from process P1 arrives for (0,4,2,0) can the request be immediately granted ??
. ISE 10CS53 UNIT 5 : MEMORY MANAGEMENT Objective: In this unit you will be able to define How memory can be shared and managed so that CPU can be utilized in a better way and system response time is improved, how multiprogramming is achieved & how different processes in an OS are protected and controlled access can be provided to programs and data. Here we includes different file operations and secondary storage management.
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What is storage hierarchy? 4 Differentiate among the following terminologies. 4* i) global vs local allocation equal vs ii) proportional allocation
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3. 4.
What is virtual memory? Explain Suppose we have a demand paged memory. The page table is held in registers. it takes 8ms to service a page fault if an empty page is available or the replaced page is not modified, and 20ms if the replaced page is modified. memory access time is 100ns. Assume that the page to be replaced is modified 70% of the time. what is the maximum acceptable page fault rate for an effective access time of no more than 200ns? 5. What is demand paging? Explain 6. What is segmentation? Explain. what is demand segmentation? 7. What are the different access methods? Explain. 8. Explain the difference between Physical and logical address 9. Explain with neat diagram internal and external fragmentation. 10. Describe the action taken by the operating system when a page fault occurs. 11. Write short notes on swap space management. 12. What is dynamic storage allocation problem? Mention the names of different methods used to solve the above problem 13. Consider a logical address space of 8 pages of 1024 words each, mapped on to a physical memory of 32 frames. i. how many bits are there in the logical address? ii) How many bits are there in the physical address? 14. detail the implementation of paging 15. What is fragmentation? Explain its types and disadvantages 16. Write a note on file types and file structures 17. What is virtual memory and give its advantages 18. What is fragmentation? Explain its types and disadvantages. jun/july 13 19. Explain the tem locality of reference and elaborate on its usefulness in presenting thrashing. 6* 20. operations that can be performed on directory 21. What is page fault and how it is handled? 22. What is thrashing and explain its cause. 23. Explain the buddy-system, used for managing free memory assigned to kernel process. (DEC2011) 24. Assume a computer with a memory size of 256K, initially empty. Requests are received for blocks of memory of 5K, 25K, 35K and 20K. Show how the buddy system would deal with each request, showing the memory layout at each stage and the status of the lists at the end.
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After allocating all the processes, what would be the effect of the 25K process terminating and returning its memory? 25. locality model and the working set model 26. Describe the LRU page replacement algorithm, assuming there are 3 frames and the page reference string is 70120304230321201701 Find the number of page faults. 27. Differentiate between External fragmentation and internal fragmentation 28. Explain with the help of supporting diagram how TLB improves the performance of a demand paging system. 29. What are the differences between internal fragmentation and external fragmentation? explain external fragmentation with an example 30. between the following a. Paging and Segmentation b) Page table and segment table 31. Explain any two page replacement algorithms 32. Explain the best fit, first fit and worst fit algorithm 33. Discuss the following page replacement algorithm with an example. i> Optimal ii> LRU 34. between global and local replacement algorithms
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Explain the 8 8*
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PESIT SOUTHCAMPUS 35.Explain the following sequence of memory references from a 460 word program. 10,11,104,170,73,309,185,245,246,434,458,364. (Dec 2012) 36. Consider the following page reference string 1,2,3,4,2,1,5,6,2,1,2,3,7,6,3,2,1,2,3,6 Find out the number of page faults if there are 4 page frames, using the following page replacement algorithm i) LRU ii) FIFO iii) Optimal 37. Consider following sequence of memory reference from a 460-byte program 10,11,104,170,73,309,185,245,246,434,458,364 i) Give reference string assume page size of 100 bytes ii) Find Page fault rate assuming 200 bytes of Physical memory available using FIFO, LRU, Optimal replacement algorithms 38. Explain segmented memory management 39. Explain paging scheme of memory management. What hardware support is needed for its implementation? 40. Explain different disk scheduling techniques with example. How are their performance measured? 41. Discuss the following page replacement algorithm with an example i) Optimal ii) LRU 42. A virtual memory system has the following specification: Size of the virtual address space=64k Size of the physical address space=4k Page size=512 Virtual page# physical frame# 0 0 3 1 7 2 4 3 10 4 12 5 30 6 31 7 find all the virtual addresses that will generate a page fault i) compute the main memory addresses for the following virtual addresses. 24,3784,10250,30780 43. The available space list of a computer memory is specified as follows: Start address block address in words 100 50 200 150 450 600 1200 400 Determine the available space list after allocating the space for the stream of requests consisting of the following block sizes: 25,100,250,200,100,150 Use i) FIRST FIT ii) BEST FIT and iii) WORST FIT algorithms. Your answer should be in terms of the given available space list format only 44. What is dynamic storage allocation? Explain the commonly used strategies for dynamic storage allocation. (DEC2011) 45. What is paging? explain with an example 46. Define 1.Thrashing 2.Beladys anomaly 3.Effective access time in demand paging 47. A process references 5 pages A, B , C, D, E in the following order A. B, C, D, A, E, B, C, E, D Assuming that the replacement algorithm is LRU and FIFO, find out the number of page faults during the sequence of references, starting with an empty main memory
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PESIT SOUTHCAMPUS With 3 frames.
48.
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Belady’s enomaly is a behavior of which which page replacement algorithm 1. FIFO 2. Optimal 3. LRU 5 Circular FIFO
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The time taken by the disk arm to locate the specific address of a sector for getting information is called __________. 1 Rotational Latency 2 Seek Time 3 Search Time 4 Response Time 1 50.
Paging is 1. virtual memory system. 2. Memory management scheme 3.Allocation of memory 4. Deadlock prevention 5. Assume a computer with a memory size of 256K, initially empty. Requests are received for blocks of memory of 5K, 25K, 35K and 20K. Show how the buddy system would deal with each request, showing the memory layout at each stage. After allocating all the processes, what would be the effect of the 25K process terminating and returning its memory? 52. Why is page replacement necessary? Explain any 3 page replacement algorithms.
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53.The purpose of virtual memory system is to a. Allow multiprocessing b. Allow multiprogramming c. Allow batch processing
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llow execution of a program that requires larger memory than the size of the physical main memory UNIT 6 : FILE SYSTEM AND ITS IMPLEMENTATION Objective: The main objective of this unit is to study the basic concepts of file system and how different types of files are implemented as well as of different access methods of files. 6 1. Explain the various file access methods 6* 2. Explain the terms: sequential file access and tree structured directories 6 3. Define file and directory. Give one implementation of file directory. 4. Explain the terms: file types, file operations and file attributes 5. An operating system supplies system calls to allow you to COPY, DELETE and 3*4 RENAME a file. Discuss the differences between using COPY/DELETE and RENAME to give a file new 5 name? 6. Explain the methods used to implement the directory. 7. Explain free space management technique. 8* 8. When the UNIX filling system opens a file, its i-node is copied into memory. It has 8 been suggested, that with memory getting cheaper that if n processes open the same file then n copies of the I-node could be held in memory. Is this a good idea? Give your reasons. 9. Write a note on directory structure 5 organization 10.Define file system. Explain the different directory structure. 8 10 11.Name the different file allocation methods. Explain the linked allocation of file 10* P E S Institute of Tech., Bangalore South Campus – Education for the Real World – Course Information – BE. V-Sem 10CS53 - 15
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PESIT SOUTHCAMPUS implementation with merits and demerits. 12. List the common file types along with its extensions and functions. (DEC2011) 13.When a file is removed, the blocks it occupies are simply placed back onto the free list. Can you see any problems with this? If so, how would you overcome them and what problems, if any, would now exist and how would you resolve these 14. How do the modern OS concurrently support multiple types of file system? Explain its implementation, in detail. (DEC2011) 15.Explain the linked allocation of disk space with a neat diagram. how does it compare with contiguous allocation 16.Discuss the various methods of allocation of disk space for file system. 17.Describe the windows NT file system and mention its special features. 18.Name the different file allocation and file access methods and clearly differentiate between them. Bring out the relative problems of contiguous allocation methods and explain how these problems are solved in linked allocation method. Bring out its relative demerits, if any 19.File system NTFS stands for 1. New type file system 2. Never Terminated file system 3. New technology file system 4. Non terminated 20.
Every file in a filing system has a set of attributes (read only, date created etc.). Assume a filing system allows an attribute of temporary, meaning the creating process only uses the file during the time it is executing and has no need for the data thereafter. Assume the process is written correctly, so that it deletes the file at the end of its execution. Do you see any reason for an operating system to have temporary file attribute? Give your reasons. 21. An operating system supplies system calls to allow you to COPY, DELETE and RENAME a file. Discuss the differences between using COPY/DELETE and RENAME to give a file new name? 22. Define file system. Explain the various file allocation methods with suitable examples. 10 23.Which of the following statements is not true? a. A directory is a special type of file b. A directory is used to store file attributes c. A directory is used to store file data d. A directory is used to store file access information UNIT 7: MASS STORAGE MANAGEMENT AND PROTECTION AND SECURITY
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Objective: The main objective of this chapter is to study the secondary storage management and how protection and security is provided by the operating system, what are the different mechanisms used and the different types of threats that a program has to face. 4 1. What are file protection methods? 5* 2. What are the different access methods? Explain. 3. 5 Explain the difference between protection and security 5 4. 6 What are the problems encountered during protection? 6 5. What is access matrix? Explain its implementation 6* 6. What are the goals of protection? 8* 7. Discuss the different file protection schemes. 8. Write a note on “Internet use policy”. 9. What is a Hacker? What are the arguments for and against hacking? 8* 10.Explain various questions that arise in revocation of access rights. (DEC2011) 8* 11.Differentiate between protection and security in file system. How they are implemented?
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P E S Institute of Tech., Bangalore South Campus – Education for the Real World – Course Information – BE. V-Sem 10CS53 - 16
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12.Discuss the various ethical issues relating to information Technology.
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13.Explain the terms „WORMS‟ and „VIRUSES‟ with reference to system threats
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14.Discuss the different methods used to solve the problem of security at the operating system level. 15.Briefly explain the various kinds of program threats and system threats.
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16.What is access matrix? Explain how the access matrix can be implemented effectively.
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17.Explain different methods used to solve the problem of security at the operating system level 18.Discuss the various ethical issues relating to information Technology. 19.Explain sector slipping, with an example. (DEC2011) 20.Describe the SSTF disk scheduling algorithm using the following data. The dist head is initially at position-cylinder 53.the cylinder sequence of requests is 98, 183, 37, 122, 14, 124, 65. 67. find the total head movement. 21.Assume the disk queue, with request fun I/O to block on cylinders as 80,30,15,100,125,90,45, and 10. If the disk head is initially at cylinder 35, illustrate the disk movements, using the SSTF scheduling algorithm. Also calculate the total head movement. (DEC2011) 22.Explain the disk structure 23.Explain the following disk scheduling algorithm with examples. iii) SSTF ii) SCAN iii)LOOK Comment on the selection of these scheduling methods. 24.With respect to disk management, explain the following : i) Boot Block ii) Bad Block concepts. 25.Suppose that a disk drive has 5000 cylinders, numbered 0 to 4999. the drive currently services a request at cylinder 143, and the previous request was at cylinder 125. the queue of pending request in FIFO order is 86,1470,913,1774,948,1509,1022,1750,130. Starting from the current position, what is the total distance(in cylinders) that the disk arm moves to satisfy all pending requests, for each of the following algorithms i)FCFS ii) SSFT iii) SCAN iv) LOOK v) C-SCAN. 26.What are the different disk scheduling algorithms explain. 27.The queue of requests in FIFO is 86,147,91,177,94,150,102,175,130 What is the total head movement needed to satisfy the requests for the following Scheduling algorithms FCFS, SJF, SCAN, LOOK, C-SCAN. 28.What is disk scheduling? Explain FCFS and SCAN disk scheduling algorithms. 29.Suppose that the head of moving head disk with 200 tracks numbered 0 to 199 is currently serving the request at track 143 and has just finished a request at track 125. If the queue request is kept in FIFO order, 86, 147, 91, 177 , 94, 150, 102, 175, 130 What is the total head movement to satisfy these requests for i) FCFS II) SSTF disk scheduling algorithm. 30. Which file system does Windows 95 typically use ?
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1 FAT16 2 FAT32 3 NTFS 4 LMFS 31. Given a disk with 200 tracks, where track requests are received in the following order 55, 58, 39, 18, 90, 160, 150, 38, 184. The starting position for the arm is track 100. Calculate the number of tracks crossed when the following algorithms are used • First Come First Serve • Shortest Seek First
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P E S Institute of Tech., Bangalore South Campus – Education for the Real World – Course Information – BE. V-Sem 10CS53 - 17
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PESIT SOUTHCAMPUS • The elevator algorithm starting in the direction UP. 32. Briefly explain, in which of the following cases can the algorithms listed above augment its performance? • A process is reading 10,000 blocks with consecutive disk addresses. • A process is reading 10,000 blocks with random disk addresses. • A process is creating child processes to read 10,000 blocks with random addresses. • Processes are communicating with each other by writing and reading blocks to disk. 33. Explain any 4 disk scheduling algorithms with a neat diagram.
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UNIT 8: CASE STUDY LINUX OPERATING SYSTEM Objective: The main objective of this chapter is to study History and development of Linux, Linux-process management and memory management, File systems, network structure and security. 1. What are components of Linux systems? 5 2. Explain Module management in Linux 5 3. What are 3 layers implemented in Linux 5 kernel. 5 4. Explain the Windows NT-design principles 5 5. Explain the networking in Windows NT 5* 6. Explain Windows-NT architecture 5* 7. What are main features of UNIX? 5* 8. Explain the process management in 5 UNIX? 9. Explain security mechanism of Linux.
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PESIT SOUTHCAMPUS 10.Write a short note on Design principle of Linux system. 11.What are the three main bodies of code in LINUX implementation? explain 12.Explain password mechanism in LINUX. 13.Explain Interprocess communication in Linux System 14.Explain Network structure, security in Linux system 15.Explain Design Principles of Linux System 16.Explain interface and memory management in Unix 17.Distinguish between fork() and clone() system call. Also customize the clone() system call to fork() functionality, with suitable modifications/settings. (DEC2011) 18.Explain block, fragments, inode and mapping of a file descriptor to an inode in UNIX-OS
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19.What are the three classes of devices in LINUX? Explain the overall structure of the device-driver system in LINUX. (DEC2011) 20.Discuss the features of LINUX operating system.
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21.Discuss the memory management with reference to Linux.
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22.Explain the three main components of a Linux system with a neat figure
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23.Unix
Operating System is an __________. 1 Time Sharing Operating System 2 Multi-User Operating System 3 Multi-tasking Operating System 4 All the Above
Note: ‘ * ‘ indicates questions appeared in previous exam papers.
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