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

Define cpu scheduling, Define CPU scheduling. CPU scheduling is the met...

Define CPU scheduling. CPU scheduling is the method of switching the CPU among several processes. CPU scheduling is the basis of multiprogrammed operating systems. By switching

Page fault handling , Page Fault Handling conditions like, where the copy...

Page Fault Handling conditions like, where the copy on write bit of a page is set and that page is send by more than one process, the Kernel assign new page and copies the conten

What are the various page replacement algorithms, What are the various page...

What are the various page replacement algorithms used for page replacement? FIFO page replacement Optimal page replacement LRU page replacement LRU approximat

How can the index blocks be implemented, How can the index blocks be implem...

How can the index blocks be implemented in the indexed allocation scheme? The index block can be implemented as follows a. Multilevel scheme b. Linked scheme c. Combin

Is disk scheduling except fcfs scheduling, Q. Is disk scheduling except FC...

Q. Is disk scheduling except FCFS scheduling useful in a single-user environment? describe your answer. Answer: In a single-user environment the I/O queue typically is empty.

Define most common phase structured grammar, Which is most common phase str...

Which is most common phase structured grammar? Most common phase structured grammar is Context – Sensitive

Changing the runlevel of system from 5 to 3 on startup, Front page We n...

Front page We need to continue or customization and documentation of our system. Currently our system boots into runlevel 5 and we need it to boot into runlevel 3. For future r

Scheduler that select process from secondary storage device, A scheduler th...

A scheduler that selects processes from secondary storage device is known as                    Medium term scheduler is a scheduler that selects processes from secondary stor

Define action that implementing meaning of instruction, Determine how Actio...

Determine how Action implementing instruction’s meaning are a actually carried out   Action implementing meaning of instruction are a actually carried out Instruction executio

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