Robert V. Baron writes:

>If you are run the uname system call from a program that is emulating
>linux, for example, it should return "linux" -- not netbsd -- as the os.

There are arguments both ways. 

NetBSD emulating <<commercial Unix brand Z>> is not really
<<commerical Unix Z>>: the emulation is ususally not complete.  Also,
Jason Thorpe, amongst others, has argued for returning "NetBSD", so
that, e.g., Webserver statistics about client hosts reflect the
existence and userbase of NetBSD.