What is CentOS?
CentOS stands for Community Enterprise Operating System. It is an Enterprise Linux distribution based on the sources from Red Hat Enterprise Linux. It provides a free, enterprise-class, community-supported computing platform.
Starting with CentOS 5 each version is supported for 10 years by means of security updates. Previous versions of the same were for 7 years. A new CentOS version is released approximately every 2 years and each CentOS version is regularly updated to support newer hardware. This results in a secure, low-maintenance, reliable, predictable and reproducible environment.
Some of the ISO images released by the CentOS project have no direct upstream equivalents. They are created for specific purposes, such as for providing a live bootable image, or for providing a reduced-size installation media.