Example of producer consumer - semaphore, Operating System

Assignment Help:

Now let's implement bounded producer-consumer with semaphores, a Coke machine which is initially empty:

semaphore sem_mutex = 1 // binary semaphore for mutual exclusion, 1==unlocked

semaphore slots_left = N
semaphore cokes_left = 0
producer()
down(slots_left)
down(sem_mutex)
insert Coke into machine
up(cokes_left)
up(sem_mutex)
consumer()
down(cokes_left)
down(sem_mutex)
buy Coke
up(slots_left)
up(sem_mutex)

Note that the down(slots left) needs to go before the down(sem mutex), and similarly for down(cokes left) and down(sem mutex), because otherwise the system can end up waiting forever. For example, imagine an empty machine with the consumer arriving ?rst, and calling down(sem mutex) before down(cokes left).

In some sense, the consumer calling down(cokes left) is a reservation to get a Coke in the future. Even if there are no Cokes currently in the machine, the consumer is reserving a claim for a future Cokewith this action. Similarly, the producer calling down(slots left) is a reservation to insert a new Coke in the future.


Related Discussions:- Example of producer consumer - semaphore

What is the use of FIFOs in client-server applications, What is the use of ...

What is the use of FIFOs in client-server applications

Protection, Can you please explain in easy words how input output protectio...

Can you please explain in easy words how input output protection works

Explain the worker model, Explain the Worker Model The Worker Model of ...

Explain the Worker Model The Worker Model of client-server application architecture provides a very good understanding of threads and their power to the developer. This exercis

Define projected allocation state is safe - banker algorithm, A system cons...

A system consists of 10 units of resource class Ru. The resource needs of three user processes P1, P2 and P3 are like this                     Using Banker's algorithm, de

Why interrupt can be used, Why interrupt can be used? The majority of t...

Why interrupt can be used? The majority of the different parts of the PC need to send information to and from the processor and they expect to be able to get the processor's at

Describe the concept of transaction atomicity, Q. Describe the concept of t...

Q. Describe the concept of transaction atomicity? Answer: A transaction is a sequence of read as well as writes operations upon some data followed by a commit operation. If the

Deadlock, Suppose we have 3 processes running at the same time as shown in ...

Suppose we have 3 processes running at the same time as shown in the following table. Each resource only has one instance. Show a possible scenario of resource allocation that r

Allocation techniques, Since most of the programs require a lot of memory a...

Since most of the programs require a lot of memory allocation/deallocation, we expect the memory management to be fast, to have low fragmentation, make good use of locality, and be

Define the executor (worker thread), Define the Executor (Worker Thread)  ...

Define the Executor (Worker Thread)  The responsibility of the Executor (or Worker Threads) is to execute instructions on behalf of a client-server connection. The Executor mus

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