Solaris is a UNIX operating system made at Sun Microsystems (now Oracle). Before version 2 it was BSD based, after version 2 it was based on SVR4. The last Sun version is Solaris_10. It worked on x86 (PC) hardware but is more commonly found on Sparc hardware. Oracles Solaris_11 works only on the sparc architecture.
We wish the folks at http://www.sun.com/software/solaris/ would add a little more to the single "hostname" binary, so that when you run "hostname foo" it would update the +5 necessary files that need touched to change ones hostname. If you want to modify your hostname and aren't sure of all of the required files, you might want to try
For the last few major revisions of Solaris, the DNS option has not worked in the installer. You will have to ignore this during installation and configure it afterwards. This issue exists as of the latest version, Solaris_10.