CDE (Common Desktop Environment) was the default working environment from Sun's Solaris 5.6 through 5.9. They've since switched to GNOME but CDE was open-sourced just a few months ago and it's what I use on Linux as well as Solaris. The clutter in that screenshot (not mine but close enough) is atypical. Generally, I keep Firefox open desktop 4 and xterms on the other three.