Write a note on the usage of semaphores, Operating System

Assignment Help:

Write a note on the usage of semaphores.

Semaphore is a synchronization tool and it is a variable having integer values. It is accessed only by two standard atomic operations wait and signal. These operation were initially termed p(for wait) and v(for signal).

                The traditional definition for wait in pseudocode is:

 

                             wait(s)  {

                                         while(s<=0)

                                           ;//no-op

                                         s--;

                                          }

             The traditional definition for signal in pseudo code is:

 

                            signal(s) {

                                             s++;

                                           }

Alteration to the integer value of the semaphore in the wait and signal operations should be executed indivisibly. i.e., when one process alters the semaphore value .No other process is able to simultaneously modify that same semaphore value. Additionally in the case of wait(s) the testing of the integer value of s (s<=0) and its possible modification (s--) must as well be executed without interruption.


Related Discussions:- Write a note on the usage of semaphores

Explain the basic method of paging method, Explain the basic method of pagi...

Explain the basic method of paging method. Physical memory is divided into the fixed-sized blocks called frames. Logical memory is as well divided into blocks of the same size

Read-write locks, Consider a large web-based database. In some sense, Googl...

Consider a large web-based database. In some sense, Google is sort of like this. There might be many users who want to read from the database, but only a few users who are allowed

Explain memory management using bit maps, MEMORY MANAGEMENT USING BIT MAPS ...

MEMORY MANAGEMENT USING BIT MAPS   In this memory is separated into different allocation units each of some particular size(a few bites).consider every space of size 4k. A

Prolog application, 1. Problem Domain You will be considering the Wumpus ...

1. Problem Domain You will be considering the Wumpus world introduced in Russell and Norvig (2009) Chapter 7. For this programming assignment you'll use Prolog's ability to do in

Define lazy swapper, Define lazy swapper. Rather than swapping the enti...

Define lazy swapper. Rather than swapping the entire process into main memory, a lazy swapper is used. A lazy swapper never swaps a page into memory unless that page will be ne

Define swapping, Define swapping. A process requires being in memory to...

Define swapping. A process requires being in memory to be executed. Though a process can be swapped temporarily out of memory to a backing store and then brought back into memo

Define a election algorithm, Consider a setting where processors are not as...

Consider a setting where processors are not associated with unique identifiers but the total number of processors is known and the processors are organized along a bidirectional ri

What methods are used to monitor intrusion detection, Question : a) Wh...

Question : a) What do you understand by a Directory Structure? Support your answer with a diagram. b) Give an example how Access Lists and Groups are arranged to mode of

How many disks can be used effectively by one fast wide bus, Q. More than ...

Q. More than one disk drive is able to be attached to a SCSI bus. Especially a fast wide SCSI-II bus can be connected to at most 15 disk drives. Remember that this bus has a bandw

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd