Hi, I've been contacted by a local training center specialized in Oracle databases, to train a group of four administrators to use Linux. They're supposed to use Oracle Linux (more exactly "OL5"), which I understand is some specialized version of Red Hat Enterprise Linux. I'm reasonably proficient with CentOS. I've been using it exclusively on desktops and servers since 2007 (version 4.3 if I remember correctly), after a few years on Slackware and Debian. I've setup CentOS-based networks in small town halls, public libraries and schools, my dedicated webserver is running the latest CentOS, and I've published a book about basic Linux concepts entirely based on CentOS 5.3. On the other hand, I've never got to work on the "real thing", so to speak. The only time I put my hands on a Red Hat Enterprise Linux server was to retrieve the root password for a distracted client (add init=/bin/bash to the kernel line in GRUB, mount -o remount,rw /, passwd :oD). And I never came near a machine running Oracle Linux. What differences can I expect between a server running Oracle Linux and my average server running CentOS ? As far as I can guess, their "unbreakable" Linux kernel will still be some package called 'kernel' (with the according 'kernel-devel' and 'kernel-headers' packages). Probably Yum will be used as a dependency resolver (will it?), only with different repositories. And for the rest, I except it to work the same, in that I can still use chkconfig, ntsysv, rpm, etc. (what about system-config-securitylevel-tui or similar tools?) In short, what differences/similarities can I expect? Is there some document stating these? Cheers from the sunny South of France, Niki Kovacs -- http://www.microlinux.fr