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 what type of group scope you will use, Question: (a) The actual...

Question: (a) The actual use and scope groups depend on the mode in which a domain is running. There are two domain modes in which you can run a Windows 2000 domain. List and d

What are the advantages of linked allocation, What are the advantages of Li...

What are the advantages of Linked allocation? The benefits are a. No external fragmentation b. Size of the file does not require to be declared

Os, why we say" OS is a resource allocator" and “OS is a control program"?

why we say" OS is a resource allocator" and “OS is a control program"?

What is an idle thread, idle thread The special thread a dispatcher wi...

idle thread The special thread a dispatcher will run when no ready thread is found. The primary purpose of the idle process and its threads is to remove what would otherwise b

Determine the syntax of the assembler directive equ, Determine the syntax o...

Determine the syntax of the assembler directive EQU The following is syntax of the assembler directive EQU: EQU

What are the different methods for handling deadlocks?, What are the differ...

What are the different methods for handling deadlocks? Deadlock detection and recovery: Permit the system to enter a deadlock state, detect it and after that rec

Define analysis for syntactic structure of source statement, An analysis, w...

An analysis, which defines the syntactic structure of the source statement, is known as Syntax analysis defines the syntactic structure of the source statement

Compute the effective instruction time on the system, Q. An operating syst...

Q. An operating system sustains a paged virtual memory using a central processor with a cycle time of 1 microsecond. It costs an additional one microsecond to access a page other

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