A legacy operating system (OS) is a computer system or software product that is no longer actively developed or supported. Legacy operating systems are typically found on older hardware systems and older software versions of applications. These systems can range from DOS (Disk Operating System) to early versions of Windows, such as Windows 95 and Windows XP, as well as Apple's Mac OS 8 and 9. Legacy operating systems can be difficult to integrate with newer hardware and software, as they often lack the necessary drivers, libraries, and support. However, these systems are still used in certain cases, such as for certain legacy applications and games, or to run legacy hardware systems.
Arch Linux
Manjaro Linux
Xubuntu
Lubuntu
Antergos
Puppy Linux
Haiku
SliTaz
Knoppix
Bodhi Linux
Porteus
Tiny Core Linux
Illumos
Pearl OS
KolibriOS
Damn Small Linux
TempleOS
Slax
WattOS
MidnightBSD
Discontinued It seems that the project is no longer updated (no release candidate since 2012, no stable release since 2008), but still fully functional.