BNT201 – OPERATING SYSTEM

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Assignment

DRIVE	SUMMER, 2015
PROGRAM	BSCNT
SEMESTER	2
SEMESTER CODE & NAME	BNT201 – OPERATING SYSTEM
BK ID	B1405
CREDIT	4
MARKS	60

Note: Answer all questions. Kindly note that answers for 10 marks questions should be approximately of 400 words. Each question is followed by evaluation scheme.

1 What is operating system? Explain any four major functions of operating system.

Answer: The operating system is the most important program that is on a computer.  The operating system basically runs the computer and allows other programs to run as well.  The operating system does all the basic things that a computer needs to do, such as recognizing inputs from the mouse or the keyboard.  It keeps track of where all the files are on the computer.  It allocates resources to the various programs that are running and it prevents unauthorized access to the computer.

2 What is hardware virtual machine? Discuss any three ways through which the software virtualization can be done.

Answer: Computer hardware virtualization is the virtualization of computers as complete hardware platforms, certain logical abstractions of their componentry, or only the functionality required to run various operating systems. Virtualization hides the physical characteristics of a computing platform from the users, presenting instead another abstract computing platform.

There are three major types of virtualization:

3 Explain the following scheduling algorithm:

a) First come First served

Answer: First-come, first-served (FCFS) – sometimes first-in, first-served and first-come, first choice – is a service policy whereby the requests of customers or clients are attended to in the order that they arrived, without other biases or preferences. The policy can be employed when processing sales orders, in determining restaurant sea

b) Shortest Job First

Answer: Shortest-Job-First (SJF) is a non-preemptive discipline in which waiting job (or process) with the smallest estimated run-time-to-completion is run next. In other words, when CPU is available, it is assigned to the process that has smallest next CPU burst.

The SJF scheduling is

4 Define deadlock. Discuss any four condition that leads to deadlock.

Answer: a deadlock is a situation in which two or more competing actions are each waiting for the other to finish, and thus neither ever does. In a transactional database, a deadlock happens when two processes each within its own transaction updates two rows of information but in the opposite order. For example, process A updates row 1 then row 2 in the exact timeframe that process B updates row 2 then row 1. Process A can't finish updating row 2 until process B is finished, but process B cannot finish updating row 1 until process A is finished

5 Explain LRU page replacement algorithm with an example.

Answer: Although LRU is theoretically realizable, it is not cheap. To fully implement LRU, it is necessary to maintain a linked list of all pages in memory, with the most recently used page at the front and the least recently used page at the rear. The difficulty is that the list must be updated on every memory reference. Finding a page in the list, deleting it, and then moving it to the front is a very time consuming operation, even in hardware.

6 What is computer virus? List the types of virus and its various infection methods.

Answer: A Computer virus is a small program that interferes with normal functions of the computer. Usually a virus program is attached to a computer file. The file to which a virus is attached is called infected file. When the infected file is copied on a disk, the virus is also copied and It hides itself on the disk.

Dear students get fully solved  assignments

Send your semester & Specialization name to our mail id :

“ help.mbaassignments@gmail.com ”

or

Call us at : 08263069601