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 scsi, What is SCSI? Ans: It is the acronym for small computer s...

What is SCSI? Ans: It is the acronym for small computer system interface. It refers to a standard bus explained ANSI. Devices such as disks are linked to a computer via 50-wire

What is ram parity, RAM parity checking is the storing of a redundant parit...

RAM parity checking is the storing of a redundant parity bit showing the parity odd or even of a small amount of computer data typically one byte stored in random access memory, an

What is laser printers, Q. What is Laser Printers? Laser Printers are p...

Q. What is Laser Printers? Laser Printers are page printers. For print quality they also face same addressability issues as DMP/InkJet Printers. Though some other methods are p

What are the advantages of electronic payment system, What are the advantag...

What are the advantages of electronic payment system? Advantages of the electronic payment system are illustrated below: This gives good security schemes. Four important sec

Explain session_start subroutines, Can you give an example of what might be...

Can you give an example of what might be best suited to place in the application_Start and Session_Start subroutines? Application Start - We can place code to initialize var

What is meant by questionnaires, What is meant by Questionnaires This ...

What is meant by Questionnaires This includes sending out questionnaires to the work force or/and to customers to find out their views of existing system and to find out how.

In what way interrupts are classified in 8085, 8085 the interrupts are clas...

8085 the interrupts are classified as Software and Hardware interrupts.

Delete a user from a category, Execute the following functionality using Ja...

Execute the following functionality using Java & SQL with simple GUI interface: 1.  Insert/delete/update an XML document.  2.  Insert/delete/update a category.  3.  Alloca

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