That's a perfectly valid question. Redhat Linux used to be the commercially sold, boxed version of Redhat meant for desktop users. After version 9 of Redhat Linux, the Redhat company decided to discontinue this and focus strictly on enterprise Linux deployments to businesses. The community-based desktop version of Redhat was given over to a side project called Fedora. Their latest version is Fedora Core 6.
Fedora is sort of the test bed for new things that may or may not end up getting used in Redhat Enterprise Linux. It's current, but not as thoroughly tested for stability and compatibility as Redhat Enterprise. Fedora is available for free.
Redhat Enterprise Linux (RHEL) is a commercially-sold desktop and server OS that Redhat sells in large numbers (100+ licenses at a time) along with service contracts to large corporations and other business customers. It is not available for free under the Redhat Enterprise name.
Since Redhat Enterprise is made of completely open-source software, Redhat does have to allow some way for people to download the sourcecode, and several projects have made their job of downloading it, compiling it, and distributing it free of charge. One of the most popular Redhat Enterprise "clones" is CentOS. This is the same product as RHEL, minus any Redhat logos and without any official company support. |