What is the difference between a process and a thread?

Question

What is the technical difference between a process and a thread?

I get the feeling a word like \'process\' is overused and there are also hardware and software threa

Answer 1

Both threads and processes are atomic units of OS resource allocation (i.e. there is a concurrency model describing how CPU time is divided between them, and the model of owning other OS resources). There is a difference in:

• Shared resources (threads are sharing memory by definition, they do not own anything except stack and local variables; processes could also share memory, but there is a separate mechanism for that, maintained by OS)
• Allocation space (kernel space for processes vs. user space for threads)

Greg Hewgill above was correct about the Erlang meaning of the word "process", and here there's a discussion of why Erlang could do processes lightweight.