Springdale Linux

Springdale Linux (formerly PUIAS Linux) has quietly rebuilt Red Hat Enterprise Linux from public sources since long before Rocky Linux or AlmaLinux existed, maintained by the mathematics/computing groups at Princeton University and the Institute for Advanced Study for their own research computing needs. It's freely available to anyone and remains a fixture in academic high-performance-computing environments, where its long track record and close RHEL compatibility matter more than name recognition. It's a lower-profile but genuinely long-running alternative in the same 'free RHEL rebuild' category Rocky and AlmaLinux now dominate.