The concept of a thread
In the field of computer science, a thread of execution is the smallest unit of programming commands (code) that a scheduler (usually as part of an operating system) can process and manage. Depending on the operating system, the implementation of threads and processes (which we will cover in future chapters) varies, but a thread is typically an element (a component) of a process.
Threads versus processes
More than one thread can be implemented within the same process, most often executing concurrently and accessing/sharing the same resources, such as memory; separate processes do not do this. Threads in the same process share the latter's instructions (its code) and context (the values that its variables reference at any given moment).
The key difference between the two concepts is that a thread is typically a component of a process. Therefore, one process can include multiple threads, which can be executing simultaneously. Threads also usually allow for shared resources...
