New to threads. How do they work?

[Lawrence D'Oliveiro]

In message <3hh3c2pu1b6a34g1u80c9s19a5hqi2omme at 4ax.com>, Dennis Lee Bieber
wrote:

> On Sat, 22 Jul 2006 17:19:22 +1200, Lawrence D'Oliveiro
> <ldo at geek-central.gen.new_zealand> declaimed the following in
> comp.lang.python:
> 
>> 
>> Perhaps because with threads, data is shared by default. Whereas with
>> processes, it is private by default, and needs to be explicitly shared if
>> you want that.
> 
> Or just that the "name" "thread" was a late-comer for some of us...
> 
> The Amiga had "tasks" at the lowest level (these were what the core
> OS library managed -- that core handled task switching, memory
> allocation, and IPC [event flags, message ports]). "Processes" were
> scheduled by the executive, but had additional data -- like stdin/stdout
> and environment variables... all the stuff one could access from a
> command line. Or, confusing for many... Processes were "DOS" level,
> Tasks were "OS" level.

Or for a more up-to-date example, how about the Linux way, where "processes"
and "threads" are just two points on a spectrum of possibilities, all
controlled by options to the clone(2) system call.