Programming .NET Components, 2nd Edition

Threads and Multithreading

In modern computing terminology, a thread is simply a path of execution within a process. Every application runs on at least one thread, which is initialized when the process within which the application runs is started up. The threads of an application always execute within the context provided by the application process. Typically, you find two kinds of operations in any application: CPU-bound and I/O-bound operations. CPU-bound operations use the machine’s central processing unit (CPU) to perform intensive or repetitious computations. I/O-bound operations are tied to an input or output device such as a user-interface peripheral (keyboard, screen, mouse, or printer), a hard drive (or any non-memory durable storage), a network or communication port, or any other hardware device.

It’s often useful to create multiple threads within an application, so that operations that are different in nature can be performed in parallel and the machine’s CPU (or CPUs) and devices can be used as efficiently as possible. An I/O-bound operation (such as disk access), for example, can take place concurrently with a CPU-bound operation (such as the processing of an image). As long as two I/O-bound operations don’t use the same I/O device (such as disk access and network-socket access), having them run on two different threads will improve your application’s ability to efficiently handle these I/O devices and increase the application’s throughput and performance. In the case ...