1. Laboratory - 4

2.  Threading Concept  Threading in.NET  Multi-Threaded Socket  Example

3.  A thread is like a replication of a process but each replication is still belonging to a same process.  Operating system concept ◦ Thread – lightweight process ◦ Process – program in memory ◦ Program – set of instruction  Thread share memory but process has its own memory

4.  Example : SimpleThread.cs  Thread class  4 constructors public Thread(ThreadStart) public Thread(ParameterizedThreadStart) public Thread(ThreadStart, int) public Thread(ParameterizedThreadStart, int)  Requires ThreadStart delegate for thread with no parameter  Thread with parameter will require ParameterizedThreadStart

5.  ThreadStart class SomeClass { void SomeThreadMethod() { // Some task to be performed here } void NormalMethod() { ThreadStart ts = new ThreadStart(SomeThreadMethod); Thread t = new Thread(ts); t.Start(); }

6.  It seems that each thread runs concurrently  But in practice, the context switching between threads are so fast, it appears parallelism  The execution order of each thread is random  In some cases, we need to have a certain task within a thread to be completed first before a context switching is carried out.  For example: Race condition (RaceCondition.cs)

7.  Many methods are available to initiate thread synchronization.  In this class we will use three synchronization technique: ◦ Lock ◦ Monitor ◦ Mutex  Example (Source code are given)

8.  Previously, server can handle only one client per time  We need to have a way to handle multiple client connection

9.  In connection-oriented protocol, the RemoteEndPoint property gets the EndPoint containing the remote IP address and port number to which the Socket is connected.  The RemoteEndPoint is set after a call to either Accept or Connect.  It is not needed to put the whole socket program within the threading method.  The part of the socket program requires to run concurrently will only be in included in multithreading method.

10.  Multi-Threaded Server

11.  Listener Flow

12.  Example: EchoServerMT.cs