What is FreeBSD and NETBSD ?
 

Are they operating system like redhat ?

Yes and no.

Red Hat is a GNU/Linux distribution. FreeBSD and NetBSD are not. They are, as their names imply, BSDs.

BSD and GNU/Linux are both open-source unix-like operating systems, but they are significantly different from one another.

This page does a good overview of the main differences:
http://www.over-yonder.net/~fullermd...bsd4linux1.php

http://www.freebsd.org/
FreeBSD is an advanced operating system for x86 compatible, AMD64, Alpha, IA-64, PC-98 and UltraSPARC® architectures. It is derived from BSD, the version of UNIX® developed at the University of California, Berkeley.