History Question

[Ben Pfaff]

There seems to be some confusion here, as is often seen, between
the kernel and the rest of the operating system.  Linux is a
kernel; GNU is a set of userland programs[1]; *BSD is both[2].

Linux and *BSD kernels aren't derived from UNIX sources.  Linux
never was; *BSD historically has some heritage, I believe.

[1] and an experimental (micro)kernel named HURD, which is little
used and has been under development since the early nineties.

[2] although BSD borrows some of its tools (compiler, etc.) from
GNU, and GNU borrows some of its code (database library, etc.)
from BSD.