Operating Systems (AD-405) - Important Questions

Write short notes on Time-sharing (and Batch processing) operating systems

What are the five major activities of an operating system with regard to memory management?

List the functions of OS. How operating system perform management task in a system?

What are the five major activities of an operating system with regard to process management?

Explain the evolution of operating systems and the characteristics of modern operating systems.

Define an operating system and explain its goals, functions and system management tasks.

What is meant by a system call, how can it be used, and how does an application program use these calls during execution?

Write short notes on following. (any two)

Consider a variant of the RR algorithm where the entries in the ready queue are pointers to the PCB

Suppose a process P wants to wait for two messages, one from mailbox A and one from mailbox B. What sequence of send and receive should it execute.

Define a semaphore for the dining philosophers problem.

Explain concurrency controls? What are the differences between real and virtual concurrency?

How process is differing from program? Describe process transition diagram in detail.

Write short notes on synchronization, paging, and system calls.

What resources are used when a thread is created? How do they differ from those when a process is created?

Explain the meaning of busy waiting, identify other kinds of waiting in an operating system, and discuss whether busy waiting can be avoided altogether.

Can a system detect that some of its processes are starving? If your answer "Yes" explain how it can? If your answer no, explain how the system can deal with the starvation problem.

Explain the importance of semaphores in OS, including binary and counting semaphores with examples.

Explain what a process is (including difference from program and overview of process management) and explain the process life cycle / process states with the process state transition diagram.

Calculate the number of page faults using optimal page replacement for a given reference string and number of frames.

Consider the following segment table. What are the physical addresses for the following logical address?

Explain the benefits of mapping objects into virtual memory.

What is Overlay? How to dynamic linking and loading perform in memory management?

Calculate the number of page faults for the given reference string and frames using FIFO, LRU and/or Optimal page replacement and compare them.

Explain segmentation and virtual/logical to physical address translation in a segmented system with diagram/example

Explain paging and segmentation and how they help remove fragmentation

Explain virtual memory and discuss advantages and disadvantages of non-contiguous storage allocation.

Give an example of an application where file data should be accessed sequentially and an example where it should be accessed randomly.

Suppose that a disk drive has 5000 cylinders numbered 0 to 4999. The drive is currently serving 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, 750, 750, 750, 130. Starting from current head position, what is the total distance that the disk arm moves to satisfy all pending request for each of following.

Explain why some systems keep track of file type while others do not, and discuss which approach is better.

Consider a file system on a disk that has both logical and physical block sizes of 512 bytes. Assume that the information about each file is already in memory. For each of three allocation strategy (continuous, linked and indexed), how is the logical to physical address mapping accomplished in this system? (for indexed allocation assume that a file is always less than 512 blocks long).

What is a file? Explain different file attributes and operations.

Explain file systems and disk organization/structure, including how data is read from and written to disk.

Calculate total head movement distance for given request queue using SSTF / SCAN / LOOK disk scheduling algorithms.

Explain the difference between SCAN and LOOK disk scheduling algorithms.

List the advantages and disadvantages of Magnetic Tape memory.

Explain in detail about various ways of free space management.

Explain the file systems used in Linux and Windows.

What is a file? Briefly explain different directory structures. What kind of directory structure is used in UNIX?

List three possible types of failures that can occur in a distributed system.

Why might a system use interrupt driven I/O to manage a single serial port but polling I/O to manage a front end processor, such as a terminal concentrator.

What aspects/features of a distributed system would be selected for a system running on a totally reliable network?

Describe a method for process migration across machines with different architectures running i) the same operating system; ii) different operating systems.

What are the advantages and disadvantages of making the computer network transparent to the user?

What are the benefits of a distributed file system (DFS) compared to a file system in a centralized system?

Explain the concept of buffering and spooling.

Discuss the design issues of a distributed operating system.

Write a short note on Remote Procedure Call (RPC).

In a multiprogramming and time sharing environment several users share system simultaneously. This situation can result in various security problems.

Write short notes: Virus