Task Process and threads- What do they mean?

What do you mean by a program?

A program is a General term for a unit of computation and is typically used in context of programming . A program is the code that is stored on your computer and may be written in any language like C, java etc,  that is intended to fulfill a certain task. There are many types of programs, including programs that help your computer function and are part of the operating system, and other programs that fulfill a particular function . These task-specific programs are also known as Applications [MS Word , Google Chrome etc]. In Windows you can see this by opening the task manager. These programs are stored in our hard disk. Once we run that program, they load into our main memory RAM. Now they are called as process.

Task Manager showing Running Applications

Now what do you mean by a process,  process is a program or part of it in execution  it is also known as an instance of a program in execution.

Process requires certain system resources like CPU memory I/O devices etc.

It is an independently  executable unit handled by an Operating System.

Sometimes to ensure better utilization of computational resources, a process is further broken up into threads Threads are also known as lightweight process because many Threads can be run in parallel that means one at a time for each process without incurring significant additional overhead. 

A process may be single threaded or multi threaded. We will discuss about process and its structure in detail later. Click Here

Process Chrome.exe which is multithreaded (36 threads). 

In the operating system context a task is defined as the program in execution and the related information maintained by the operating system for the program.