El Reg maps the tributaries
Red Hat has released CentOS Stream 9, the first major version since the company badly shook its community by announcing it was ending traditional CentOS a year ago. This is the second release of the new CentOS Stream distro, and presumably the IBM subsidiary hopes it will offer a more appealing migration path for CentOS users than for them to jump ship. Notably, in CentOS Stream 8, RH’s Application Streams – analogous to Fedora’s «Modularity» – were mandatory, but they’re optional in 9. This is a big deal in the Red Hat world, but can be mysterious to the millions of non-Red Hat Linux users. Since it seems to please Red Hat to imagine that Red Hat is the entirety of the Linux world, its official materials don’t really give you any context, so The Register will try to translate for you. The original Red Hat Linux (RHL) was released in May 1995, making it one of the oldest distros, but the company killed it off after version 9 in 2003. RHL was replaced with Red Hat Enterprise Linux (RHEL), which became the company’s only supported distro. The word supported is key here. The pre-existing Fedora project, formerly a third-party repo for RHL add-ons, got promoted to being the free, unsupported, community distro: no paid support, updates for 13 months, a new version roughly twice a year, and upgrades from one version to the next could be tricky, although that’s much better now. Fedora tends to be pretty bleeding-edge compared to most regular-release-cycle distros – that’s why the codeword «innovative» features heavily in the project’s mission statement. The Reg has liked Fedora for a long time. The new shiny that works in Fedora, when it ends up boring and stable, goes into RHEL. As RH puts it, Fedora is «upstream» of RHEL. RHEL, on the other hand, was and is commercial: you can only get RHEL by buying it, which in reality means buying a support contract. But it’s still FOSS, meaning that RH is legally required to make the source code available. So anyone – not just customers – could download Red Hat’s source code packages for each and every package in RHEL, free of charge, and recompile them all to build a free clone of RHEL. Various third parties started doing this and producing independent distros which were RHEL-compatible, such as Scientific Linux (from FermiLab) and White Box Linux (from the Beauregard Public Library in Louisiana). The biggest of these, CentOS (Community Enterprise OS), started in 2004. The idea of these distros is that they are basically identical to RHEL, but with the names changed. Not just the same commands, but the same versions of the same binaries, with the same config files, in the same directories, for perfect compatibility.
