Process:

• Scheduling done by OS
• Own virtual address space
• Can communicate with other processes using IPC methods
• Each process can have multiple states of code executions, i.e. threads

Thread:

• Has its own instruction pointer
• Has a state of the registers in the processor

Fiber:

• A "manual version" of a thread, i.e. without hardware backing
• A software method of overlapping work

• libdill: C library that makes writing structured concurrent programs easy
• libcsp: concurrency in C using Communicating sequential processes (CSP) model