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

Quantum settings denoted by q, Determining the time quantum for a job is a ...

Determining the time quantum for a job is a critical task. Given the assumptions that the average switching time between processes is s, and the average amount of time an I/O bo

System structures, advantages and disadvantages of monolithic and layered a...

advantages and disadvantages of monolithic and layered approach

Error detection, about error detection in operating system and how does it ...

about error detection in operating system and how does it take place?

Explain the concept of reentrancy, Concept of Reentrancy   It is a ...

Concept of Reentrancy   It is a useful, memory-saving method for multiprogrammed timesharing machines. A Reentrant method is one in which multiple clients can share a singl

Deadlock-avoidance algorithm, Regard as a computer system that runs 5000 jo...

Regard as a computer system that runs 5000 jobs per month with no deadlock-prevention or deadlock-avoidance scheme. Deadlocks take place about twice per month and the operator must

CPU, TURNAROUND TIME

TURNAROUND TIME

What resources are utilized when a thread is created, Q. What resources are...

Q. What resources are utilized when a thread is created? How do they vary from those used when a process is created? Answer: For the reason that a thread is smaller than a pr

Explain segmentation hardware?, Explain segmentation hardware? We defin...

Explain segmentation hardware? We define an completion to map two-dimensional user-defined addresses into one-dimensional physical addresses. This mapping is affected by means

Obelia, what do obelia eat and how do they feed

what do obelia eat and how do they feed

Explain deadlock avoidance, Deadlock Avoidance It's a method to evade ...

Deadlock Avoidance It's a method to evade deadlock by careful resource scheduling. This approach to the deadlock problem foresees deadlock before it actually occurs. This a

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