Our No. 1 open source operating system has to be Linux -- and our server has to be CentOS. In a nutshell, CentOS is the source code of Red Hat Enterprise Linux provided under a different label, without the maintenance and support of Red Hat and, consequently, without the cost of a Red Hat support contract. For Linux admins who don't need that support, CentOS amounts to a free and unadulterated version of RHEL, and users can count on updates that follow quickly in the wake of Red Hat's changes. FULL REPORT ...