What's the DIFFERENCE between Linux and NetBSD?

The two operating systems are generally very similar, but they have some
important differences:

Linux behaves more like System V UNIX, while NetBSD is more similar to
the Berkeley flavors of UNIX.  From an end user perspective, Linux tends
to support more and newer hardware, and tends to have a larger share of
users.  NetBSD tends to support less new hardware, but its support for
existing hardware is always very solid.  Linux comes in several
distributions from different groups such as RedHat, Debian, Caldera, and
Slackware, whereas NetBSD has only one distribution.

NetBSD also supports more platforms.  At the time of this writing,
NetBSD supports DEC Alpha, Amiga, Acorn ARM, Atari, HP 9000/300,
i386-family PC, m68k Macintosh, m68k MVME, PC532, DEC MIPS, Sun SPARC,
Sun3, Sun 3x, DEC Vax, and Sharp X680x0.  Linux supports DEC Alpha,
i386-family PC, Sun SPARC, m68k systems (such as Amiga and Atari),and
Power Macintosh.  A port for the MIPS processor is also currently being
developed. On both NetBSD and Linux, however, the Athena environment has
only been ported to the i386-family PC.