JNTU
JNTU MCA 2019 OPERATING SYSTEMS Previous Question Paper (April/May - 2019 - R13)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 20 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 8 marks and may have a, b, c as sub questions.
Part A
5 × 4 Marks = 20
Explain about the virtual memory.
Answer
Virtual memory is a memory management technique that provides an idealized abstraction of the storage resources available on a machine, creating the illusion of a large main memory. It allows the execution of processes that may not be completely in physical memory. By mapping virtual addresses used by a process to physical addresses in RAM, the operating system can store only the currently active parts of a program in physical memory while keeping the remainder on secondary storage (disk), thereby increasing the degree of multiprogramming.
Explain the process state transition diagram with neat sketch.
Answer
A process transitions through various states during its lifecycle. The states are: New (process being created), Ready (waiting to be assigned to a processor), Running (instructions are being executed), Waiting/Blocked (waiting for an event like I/O), and Terminated (process finished execution). The transitions occur as follows: New to Ready (admitted), Ready to Running (scheduler dispatch), Running to Ready (interrupt), Running to Waiting (I/O or event wait), Waiting to Ready (I/O or event completion), and Running to Terminated (exit).
Explain the concept of thrashing and why thrashing should be avoided in a system?
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List the common file types along with their extensions and describe each file type?
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Describe the conditions under which a deadlock situation may arise?
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Part B
5 × 8 Marks = 40
State and explain various types of computer systems?
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Distinguish between multiprogramming, multitasking and multiprocessing?
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Describe the functionalities listed below:
- Batch programming
- Virtual Memory
- Time sharing
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Describe dining-philosophers problem? Derive an algorithm to solve the problem using semaphores?
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State the requirements that a solution to the critical section problem must satisfy?
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Consider the following set of processes with the length of the CPU burst time given in milliseconds: Process P1 (10,3), P2 (1,1), P3 (2,3), P4 (1,4), P5 (5,2). The processes are assumed to have arrived in the order p1, p2, p3, p4, p5 all at time 0.
a) Draw four Gantt charts illustrating the execution of these processes using FCFS, SJF, non pre-emptive priority and RR (quantum=1) scheduling.
b) What is the turnaround time of each process for each of the scheduling algorithms?
c) What is the waiting time of each process for each of the scheduling algorithms? Which of the schedules in part a results in the minimal average waiting time?
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Given memory partitions of 100K, 500K, 200K, 300K, and 600K (in order), how would each of the First-fit, Best-fit, and Worst-fit algorithms place processes of 212K, 417K, 112K, and 426K (in order)? Explain which algorithm makes the most efficient use of memory?
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State and explain about virtual memory concept with neat diagram?
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Explain the basic Scheme of page replacement and about the various page replacement strategies with examples?
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Explain about the structure of Directory.
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Explain about the Free space management in file system.
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Explain the following in detail with respect to disk: a) Seek time b) Latency c) Access time d) Transfer time
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List the implementation techniques of access matrix?
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List any two example systems that implement capability-based protection?
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Consider the following snapshot of a system. Answer the following questions using the banker’s algorithm:
a) What is the content of matrix “Need”?
b) Is the system in a safe state?
c) If a request from process P1 arrives for (0, 4, 2, 0) can the request be granted immediately?
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