What are semaphores, Computer Engineering

Assignment Help:

What are semaphores?

Semaphore: A semaphore is a synchronization tool which gives a general-purpose solution to controlling access to critical sections. It s an abstract data type (ADT) which defines a nonnegative integer variable that, apart from initialization, is accessed simply through two standard operations that are: wait and signal. The typical definition of wait in pseudo code is

wait(S){

          while(S<=0)

                 // do nothing

                          S--; }

The classical definitions of signal in pseudo code is signal(S){

                    S++; }

While one process modifies the semaphore value, anno one process can concurrently modify that similar semaphore value. As well, in the case of the wait(S), the testing of the integer value of S (i.e. S<=0), and its possible modification(S--), should also be executed without interruption.


Related Discussions:- What are semaphores

What is microcomputer system, Q. What is microcomputer system? The micr...

Q. What is microcomputer system? The microcomputer has a single microprocessor and a number of RAM and ROM chips as well as an interface unit which communicates with several ex

Find out the access time of ROM using bipolar transistors, The access time ...

The access time of ROM using bipolar transistors is about ? Ans. About 1 µ sec is the access time of ROM using bipolar transistors.

Using library methods returns number of threads, Q. Using Library methods r...

Q. Using Library methods returns number of threads? #include void subdomain(float x[ ], int istart, int ipoints) { int i; for (i = 0; i x[istart+i] = 123.456;

What do you mean by directives, Q What do you mean by Directives? Assem...

Q What do you mean by Directives? Assembly languages support numerous statements. This allows you to control the way in which a source program assembles and list. These stateme

Representations or languages - artificial intelligence, Representations/Lan...

Representations/Languages Used: Many people are taught "AI" with the opening line: "The three most important things in "AI" are  representation, representation and representat

Give explanation of user datagram protocol, Explain UDP (User Datagram Prot...

Explain UDP (User Datagram Protocol). UDP utilizes a connectionless communication paradigm. It is an application of using UDP doesn't require preestablishing a connection befor

QUELING SYSTEM, Q.SHOW THAT AVERAGE NUMBER OF UNIT IN A (M/M/1) QUELING SYT...

Q.SHOW THAT AVERAGE NUMBER OF UNIT IN A (M/M/1) QUELING SYTEM IS EQUAL TO P/(1-p). NOTE:P=ROW

Differentiate among validation and exception testing, Differentiate between...

Differentiate between validation and exception testing. - Validation testing is done to test software in conformance to requirements specified. It aims to demonstrate that soft

Write a program to event advertised, A museum has a collection of old poste...

A museum has a collection of old posters advertising events of various kinds (theatre, sport, fairs, lectures etc.). It wishes to keep a record of these, containing, for each poste

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