1.torvalds / linuxLinux kernel source treeCOther license254K total67K forks+3,902 starsfrom 250,391 · score 8.27
2.HeyPuter / puter🌐 The Internet Computer! Free, Open-Source, and Self-Hostable.desktopdesktop-environmentosjsweb-desktopwebtopcloud-os+14 moreTypeScriptAGPL-3.044K total4.1K forks+496 starsfrom 43,575 · score 6.21
3.reactos / reactosA free Windows-compatible Operating Systemoperating-systemckernelososdevx86+7 moreCGPL-2.018K total2.3K forks+295 starsfrom 18,132 · score 5.69
4.jordanhubbard / daemonarchyA new desktop installer and curated and signed package ecosystem for FreeBSD; inspired by Omarchy, FreeBSD and the classic world of video gamesPythonNo license234 total9 forks+236 starsfrom 2 · score 5.47
5.mit-pdos / xv6-riscvXv6 for RISC-VCOther license11K total4.6K forks+177 starsfrom 10,566 · score 5.18
6.SerenityOS / serenityThe Serenity Operating System 🐞operating-systemc-plus-plusosunixdesktop-environmentkernel+1 moreC++BSD-2-CLAUSE34K total3.5K forks+106 starsfrom 33,836 · score 4.67
7.microsoft / MS-DOSArchivedThe original sources of MS-DOS 1.25, 2.0, and 4.0 for reference purposesms-dosAssemblyMIT32K total4.7K forks+6 starsfrom 32,252 · score 1.95