CentOS
From ISSW
The Community Enterprise OS (CentOS - homepage) is a de-branded version of RedHat Enterprise Linux (RHEL) compiled from source binaries. It aims to be binary compatible with RHEL.
Unlike RHEL it is not supported by IBM as a platform for WebSphere products. However, since it does not require a RedHat subscription to obtain updates, it is an ideal choice for engagements where explicit support is not required, eg. proof of concepts.
The latest version is 5.2.
