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 process states in the unix system, Process States A total of n...

Process States A total of nine states are acknowledged by the UNIX system. They are like as follow: User running                                                   Executing

Permanently starves cpu-bound programs, Q. Presume that a scheduling algori...

Q. Presume that a scheduling algorithm at the level of short-term CPU scheduling favours those processes that have used the least processor time in the recent past. Why this algori

Define fifo page replacement algorithm, Define FIFO Page Replacement Algori...

Define FIFO Page Replacement Algorithm This policy simply eliminates pages in the order they arrived in the main memory. By using this policy we simply remove a page based upo

What are placement and replacement algorithms, Placement algorithms :calcu...

Placement algorithms :calculate where in available real-memory to execute a program. Common functions are next-fit, first-fit, and best-fit. Replacement algorithms :are

Give an overview of windows 2000 file management, Give an overview of WINDO...

Give an overview of WINDOWS 2000 file management. Windows makes use of the NTFS and File Allocation Table file systems. The Older versions of the FAT file system had file name

Explain linked list allocation using index, Linked list allocation using in...

Linked list allocation using index The blocks don't have a fixed size. Pointers are utilized to point to the next block in a file. The pointers are set aside as a separate tabl

What is spooling, What is spooling? Spooling overlaps the I/O of single...

What is spooling? Spooling overlaps the I/O of single job with the computation of other jobs.

Linux os, Introduction of linux

Introduction of linux

Virtual addresses, Virtual addresses are made up of two parts: the ?rst par...

Virtual addresses are made up of two parts: the ?rst part is the page number, and the second part is an offset inside that page. Suppose our pages are 4kb (4096 = 212 bytes) long,

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