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 a reference string, What is a reference string? An algorithm is...

What is a reference string? An algorithm is evaluated by running it on a particular string of memory references and computing the number of page faults. The string of memory re

Describe the actions of sun ultra sparc processor, Q. The Sun Ultra SPARC p...

Q. The Sun Ultra SPARC processor has numerous register sets that describe the actions of a context switch if the new context is previously loaded into one of the register sets. Wha

Memory management, what is hashed page tables & explain of there work & fig...

what is hashed page tables & explain of there work & figure

How program execute in operating system, Q. How Program execute in operatin...

Q. How Program execute in operating system? Program execution: Operating system loads a program in memory and executes the program. The program should be able to end its exec

Explain a method for process migration, Q. Process migration in a heterogen...

Q. Process migration in a heterogeneous network is typically impossible given the differences in architectures and operating systems. Explain a method for process migration across

Discuss various services provided by the operating system, List and discuss...

List and discuss the various services provided by the operating system. Program execution - system capability to load a program into memory and to run it. I/O operatio

Batch oriented and interactive operating system., properies of Batch orient...

properies of Batch oriented and interactive operating system.

Convert the hex to binary, Convert the following from hex to binary and dra...

Convert the following from hex to binary and draw it on the memory map.     RAM    = 0000 -> 00FF     EPROM = FF00  -> FFFF Answer:   0000  0000 0000  0000 (0)    RAM sta

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