[CentOS] CentOS vs. RHEL vs. Oracle Linux ?

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