"These days, when one talks about free software, the first word that comes to mind is Linux--be it the kernel or a distribution based on it (which would then be a GNU/Linux operating system, and its flavour marked by a brand name: Red Hat, SuSE, Mandriva, Debian, Ubuntu, Slackware...)
"At one time, there was another project worthy of note: BeOS. It wasn't POSIX-compatible, but it was neat. But now, only free *NIX prevail... really?
"Enter ReactOS..."