What is a thread?
Every OS provides abstractions to allow multiple programs to share the same hardware resources, such as CPU, memory, and input and output devices. The process is one of those abstractions, providing a reserved virtual address space that its running code cannot escape from. This basic sandbox avoids the process code interfering with other processes, establishing the basis for a balanced ecosystem. The process has nothing to do with code execution, but primarily with memory.
The abstraction that takes care of code execution is the thread. Every process has at least one thread, but any process code may request the creation of more threads that will all share the same virtual address space, delimited by the owning process. Running multiple threads in a single process is roughly equivalent to a group of woodworking friends working on the same project –they need to be coordinated, paying attention to each other's progress, and taking care not to block each...
