1 Pertemuan 6 Komunikasi antar Proses (IPC) Lanjutan Matakuliah: T0316/sistem Operasi Tahun: 2005 Versi/Revisi: 5 OFFCLASS01.

Presentasi berjudul: "1 Pertemuan 6 Komunikasi antar Proses (IPC) Lanjutan Matakuliah: T0316/sistem Operasi Tahun: 2005 Versi/Revisi: 5 OFFCLASS01."— Transcript presentasi:

1 1 Pertemuan 6 Komunikasi antar Proses (IPC) Lanjutan Matakuliah: T0316/sistem Operasi Tahun: 2005 Versi/Revisi: 5 OFFCLASS01

2 2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : menerangkan interprocess communication tanpa busy waiting (C2)

3 3 Outline Materi Semaphore Mutexes Monitor Message Passing

4 4 Operation DOWN and UP are Atomic Action INTERPROCESS COMMUNICATION (Cont’d) SEMAPHORES  Integer variable to count the number of wakeups  It is 0 if there is no wakeup, or some positive value if one or more wakeups were pending 1.DOWN (S) S = S – 1 IF (S < 0) THEN SLEEP 2.UP (S) S = S + 1 IF (S <= 0) THEN WAKEUP Two operations on semaphore: 1.DOWN (S) IF (S > 0) THEN S = S – 1 ELSE SLEEP Or alternatively

5 5 The producer-consumer problem using semaphores

6 6 Implementation of mutex_lock and mutex_unlock MUTEXES  Variable that can be one of two states: unlocked or locked

7 7 MONITORS  Higher level synchronization primitives  A collection of procedure, variables and data structure that are all packed together into a module A monitor

8 8  Only one monitor procedure can be active at a time  Buffer has N slots Producer-consumer problem using monitors

9 9 MESSAGE PASSING Two primitives:  Send (destination, &message)  Receive (source, &message) Design issues for message passing system  Message lost  Acknowledgement  Domains  Authentication  Performance

10 10 Implementation of producer- consumer problem using message passing

11 11 Several variants of message passing:  Mailbox  Buffering mechanism  Rendezvous  No buffering mechanism