What is the difference between a process and a thread?

The difference between a process and a thread lies in their structure and resource management within an operating system.

A process is essentially an independent program that is being executed. It has its own memory space and resources, which means that processes run in isolation from one another. This independence ensures that a problem in one process does not directly affect another. Each process includes the program code and its current activity, as well as its own set of system resources, including memory, file handles, and execution context.

On the other hand, a thread is a smaller unit of execution that exists within a process. Threads share the same memory space and resources allocated to the process they belong to, allowing for efficient communication and data sharing. However, this also means that if one thread causes a fault (like an exception or crash), it can affect the entire process and all the threads within it.

By recognizing that a process is essentially a standalone program with its resources while a thread is a lightweight entity that relies on the process context it operates in, it becomes clear why the selected answer accurately captures the distinction between these two fundamental concepts in operating systems.