[thayne]

PaulDavisThe1st is saying that the Unix pattern of forking a process (and not calling exec) was an early form of multi-threading (or multi-processing), but unlike threads in NT and later pthreads, they didn't share memory and communication between them required some form of IPC.

[PaulDavisThe1st]

Yep, absolutely corrrect. It was true at the lowest level (the semantics of fork) and it was true at the app/platform design level: in Windows you used threads inside a process, on Unix you used multiple communicating processes.

This obviously changed as pthreads came into being, and at this point, I suspect that the typical use for threads-sharing-memory and threads-not-sharing-memory is the same on most platforms.

A reminder that the task_t data structure describes threads and processes not just in Linux, but earlier Unixen also.