mcs – 041 block 1 unit 3 interprocess communication and synchronization

7/31/2019 MCS 041 Block 1 Unit 3 Interprocess Communication and Synchronization

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MCS 041

Block 1 Unit 3Interprocess Communication And Synchronization

By

Kirit A. Dhabalia


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Content

Interprocess Communication

Interprocess Synchronization

Semaphores Locks

Monitors and Condition Variables


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Supported by OS, allow one process to communicate with anotherprocess. Could be on same computer or different computerconnected through a network

It is not generally supported by single process operating systemssuch as DOS. OS/2 and MS windows support an IPC mechanism

called Dynamic Data Exchange If process needs to print its result, it must request the OS gives

access to the printers device driver. OS must decide to grant theaccess, provided printer is not being used by another processotherwise process will be waiting until availability.

Critical resource: It is a resource shared with constraints on its use(memory, files, printer )

Critical Section : It is code that accesses a critical resource

Mutual Exclusion : both processes do not attempt to use theresource at the same time (Ex. Printer)


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Shared-Memory System

Message-Passing System

Direct

Indirect

Capacity Link

Zero Capacity

Bounded Capacity

Unbounded Capacity


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Interprocess Synchronization

Serialization

Mutexes: Mutual Exclusion

Critical Sections: The Mutex Solution

Bakerys Algorithm

Semaphores Classical Problems In Concurrent Programming

Producers/Consumers Problems With a unbounded buffer

With a bounded buffer

Readers and Writers Problem

Dining Philosophers Problem

Sleeping Barber Problem


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Classical Problems In Concurrent Programming

Producers/Consumers Problem

With an unbounded buffer

With a bounded buffer

Readers and Writers Problem

Dining Philosophers Problem

Sleeping Barber Problem


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Locks

Locks are another synchronization mechanism

These locks has got two operation

Acquire

Release

A process will acquire a lock before accessinga shared variable and later it will be released

The difference between a lock and asemaphore is that a lock is released only bythe process that have acquired if earlier


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Monitors And Condition Variables

While using semaphores and locks, one must bevery careful, because a simple spelling mistakemay lead that the system ends up in a deadlock

Monitors are written to make synchronizationeasier and correctly.

Monitors are some procedures, variables anddata structures grouped together in a package

If a process cannot enter the monitor it mustblock itself. This operation is provided by thecondition variables


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Thank You

mcs – 041 block 1 unit 3 interprocess communication and synchronization

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