DRONACHARYA COLLEGE OF ENGG GR. NOIDA Operating System Subject Code : TCS-601
CSE/IT VIth
Q.1) Write down the essential difference between the following types of operating systems. 1. Batch System 2. Real Time System 3. Time Sharing System. 4. Interactive 5. Distributed 6. Network Q.2) What are the major activities or functions or properties of an operating system. Or Why is an operating system needed and how does an O.S work? Q.3) What is the difference between User mode and kernel mode? List the various services provided by an O.S. Explain System calls and system program in brief. Q.4) Why is it expensive to switch between process? Is it less expensive to switch between threads? Justify your answers. Q.5) Discuss the following 1) Multiprogramming 2) Multitasking 3) Shell 4) Kernel 5) Thread 6) Process Q.6) Explain semaphores. How can semaphore be used to enforce mutual exclusion? Give a suitable example to explain. Q.7) Explain Critical Section Problem with suitable example. Explain Inter Process Communication. Q.8) Explain how monitors are implemented using semaphore. Q.9) What do you understand by Process? Explain various state of a process with suitable datagram. Explain PCB?
Q.10) Draw and Explain the “Process Transition Diagram”. Q.11) What is dekker’s Algo.What is race condition? Give few examples of arising of Race –condition in concurrent process. Q.12) Explain the followings 1. Producer consumer Problem. 2. Reader Write Problem. Q.13) It is proposed to use a multi-recourse Banker’s algo in an Operating System containing 3 classes. The no. of resources units available for allocation in 7,7 and 10 respectively. The Resource allocation stack in shown as Process P1 P2 P3
Allocation R1 R2 R3 2 2 3 2 0 3 1 2 4
Max R1 R2 R3 3 6 8 4 3 3 3 4 4
Available R1 R2 R3 7 7 10
1. Is the current allocation stack safe? 2. Would the following request be granted n the current stack? Process P1 requests (1, 1, 0) Process P2 requests (0, 1,0) Process P1 requests (01,0) Q.13) Consider the system with five process and three resources types at time to, the following snap shots of the system has been taken Process P1 P2 P3 P4 P5
Allocation R1 R2 R3 0 1 0 2 0 0 3 0 2 2 1 1 0 0 2
R1 7 3 9 2 4
Max R2 R3 5 3 2 2 0 2 2 2 3 3
Available R1 R2 R3 3 3 2
Show the system is in Safe State .Find the safe sequence. Q.14) Consider the following Snap shot of a system Process P1
Allocation R1 R2 R3 R4 0 0 1 2
Max R1 R2 R3 R4 0 0 1 2
Available R1 R2 R3 R4 1 5 2 0
P2 P3 P4 P5
1 1 0 0
0 3 6 0
0 5 3 1
0 4 2 4
1 2 0 0
7 3 6 6
5 5 5 5
0 6 2 2
1. Obtain the array ‘Need’? 2. Is the system in a Safe System? 3. If a request from Process P1 arrives fir (0, 4, 2, 0) can the request be immediate granted. Q.15) Discuss Elevator Algo for Disk Scheduling with example Q.16) Explain the following 1. File Attributes 2. File Access 3. Explain link List Allocation Method of Files. Q.17) Explain (1) Interrupt Driven I/O. (2)Blocky and Non-Blocky Q.18) Latency Optimization usually has little effect as system performance except under heavy loads .Why? Q.19) State the advantages and Disadvantages of placing functionality in a devices controller rather then in the Kernel . Q.20) Suppose that a disk has 5000 Cylinders .The drive is currently servicing a request .pending request in FIFO order is 80,1470,913,1774,948,1509,1022,1750,130. What is the total distance that the drive arms moves for the following algo. 1. FCFS 2. SSTF 3. LOOK 4. C-SCAN Q.21) What is the causes of thrashing? how to eliminate this problem. How many page fault would occurs for the following reference string, for four page frames using FIFO, LRU, Optimal algorithm 1,2,3,4,5,5,3,4,1,6,7,8,7,8,9,7,8,9,5,4,5,4,2. Q.22) Given memory partition of 100K, 500K, 200K, and 300K. how would each of the First fit, Best Fit and worse Fit algorithm places process of 212K,417K,122K and 426K (in order) which algorithm makes the most efficient use of memory. Calculate the size of memory wasted due to external and internal fragmentation.
Q.23) Describe the segmented paging scheme of memory management and the hardware required to support the system. Explain the page replacement algorithms. Q.24) Sets of processes are going to execute on sigle cpu they are Process P1 P2 P3 P4 P5
Arrival Time 0 3 5 7 19
CPU Burst Time 14 12 07 04 07
Determine the sequence of execution for round robin quantum size =4 and also calculate Avg. Waiting time for FIFO,SJF (Non Preemptive, Preemptive) Both. Q.25) Consider a paging system with the page table stored in memory. i) If a memory tags 200ns. How long does a paged memory reference takes. ii) If we need TLB and 75% of all page table reference are found in the TLBs. What is the effective reference time (Assume that Finding a page table entry in TLBs takes 0 times, if the entry is there)