| Name | License | Kernel type | Kernel programming language | Kernel thread support | OS family | Oldest non-EOL version | Forks |
| Linux | | Monolithic with modules | C | 1:1 | Unix-like | 4.4 | elks |
| FreeBSD | | Monolithic with modules | C | 1:1 | BSD, Unix-like | 13.5 | DragonFly BSD |
| OpenBSD | | Monolithic | C | 1:1 | BSD, Unix-like | 6.4 | MirOS |
| NetBSD | | Monolithic with modules | C | 1:1 | BSD, Unix-like | 7.0 | OpenBSD |
| DragonFly BSD | | Hybrid | C | 1:1 | BSD, Unix-like | | |
| OpenSolaris, illumos | | Monolithic with modules | C | 1:1, M:N | Unix | | |
| Darwin, OpenDarwin | | Hybrid | C, C++ | 1:1 | BSD, Unix, Unix-like, OS X | | |
| OpenHarmony | | Multi-kernel | Various | 1:1, M:N, POSIX | HarmonyOS, LiteOS | 3.0.1 LTS | Oniro OS, HarmonyOS |
| Oniro | | Multi-kernel | Various | 1:1, M:N, POSIX | OpenHarmony | 3.2 LTS | |
| MINIX | | Microkernel | C | | Unix-like | | |
| RedoxOS | | Microkernel | Rust | | Unix-like | | |
| FreeRTOS | | RTOS | C | | RTOS | | |
| FreeDOS | | Monolithic | C | | DOS | 1.1 | |
| Genode | | Microkernel | C++ | 1:1 | Genode | | |
| Haiku | | Hybrid | C, C++ | | BeOS | | |
| House | | | Haskell | | own/original | | |
| KolibriOS | | Monolithic | ASM | | MenuetOS | | |
| MenuetOS | | Monolithic | ASM | | own/original | | KolibriOS |
| GNU | | or Monolithic | C | 1:1 | Unix-like | 2.4 on Linux-libre kernel | Linux |
| ReactOS | | Hybrid | C, C++ | | Windows-like | | |
| RISC OS | | Monolithic | ARM assembly, C, BBC BASIC | | RISC OS | | RISC OS 6 |
| L4, Fiasco, Pistachio | | Microkernel | C++ | | L4 | | |
| Plan 9 | | Hybrid | C | 1:1, 1:M Cothread style. | own, Unix informed | | Inferno, Plan B, 9front |
| AROS | | Exokernel | C | | AmigaOS | | |
| Syllable | | Hybrid | C, C++ | 1:1 | Unix-like, BeOS, AmigaOS, POSIX | | |
| Inferno | | | C | | Plan 9 | | OzInferno |
| NuttX | | RTOS | C | | RTOS | | |
| eCos | | RTOS | C, C++ | | RTOS | | |
| RTEMS | | RTOS | C and ASM with native support for other languages including C++ and Ada | POSIX, RTEID/ORKID, uITRON | RTOS | 4.7.1 | |
| HelenOS | | Microkernel | C | M:N | own/original | | |
| E/OS | | Monolithic | ASM, C | 1:1 | BeOS, Unix-like | | |
| TempleOS | | Monolithic | HolyC, C, C++ | | Commodore 64-like | | - |
| | Microkernel | C, C++, Assembly, Makefile, IGOR Pro | | OS/2-like | | |
| Name | License | Kernel type | Kernel programming language | Kernel thread support | OS family | Oldest non-EOL version | Forks |
| Name | x86, i386, | x86 SMP | Xen | IA-64 | x86-64 | PowerPC | PowerPC SMP | SPARC32 | SPARC SMP | Alpha | MIPS | ARM | XScale | M68k | PA-RISC | OpenRISC | Elbrus | LoongArch | SuperH | z/Architecture | others | hosted mode |
| Linux | | | | | | | | | | | | | | | | | | | | | FR-V, Cell, ETRAX CRIS, M32R, Xtensa, h8, s390, SuperH | UML, coLinux, MkLinux, , |
| FreeBSD | | | | | | | | | | | | | | | | | | | | | PC98 | |
| OpenBSD | | | | | | | | | | | | | | | | | | | | | | |
| NetBSD | | | | | | | | | | | | | | | | | | | | | SuperH, ns32k, VAX, hppa, M68010, mipseb, mipsel, sh3eb, sh3el, sparc64 | |
| DragonFly BSD | | | | | | | | | | | | | | | | | | | | | | |
| OpenSolaris illumos | | | | | | | | | | | | | | | | | | | | | | |
| Darwin, OpenDarwin | | | | | | | | | | | | | | | | | | | | | | |
| OpenHarmony | | | | | | | | | | | | | | | | | | | | | | |
| Oniro | | | | | | | | | | | | | | | | | | | | | | |
| MINIX | | | | | | | | | | | | | | | | | | | | | | |
| FreeDOS | | | | | | | | | | | | | | | | | | | | | | |
| Genode | | | | | | | | | | | | | | | | | | | | | RISC-V | Linux |
| Haiku | | | | | | | | | | | | | | | | | | | | | RISC-V | |
| KolibriOS | | | | | | | | | | | | | | | | | | | | | | |
| MenuetOS | | | | | | | | | | | | | | | | | | | | | | |
| GNU | | | | | | | | | | | | | | | | | | | | | FR-V, Cell, ETRAX CRIS, M32R, Xtensa, h8, s390, SuperH | UML, |
| ReactOS | | | | | | | | | | | | | | | | | | | | | | |
| RISC OS | | | | | | | | | | | | | | | | | | | | | | Genode |
| L4, Pistachio | | | | | | | | | | | | | | | | | | | | | | Genode |
| Plan 9 | | | | | | | | | | | | | | | | | | | | | See | lguest, vx32 |
| AROS | | | | | | | | | | | | | | | | | | | | | | , |
| Syllable | | | | | | | | | | | | | | | | | | | | | | |
| Inferno | | | | | | | | | | | | | | | | | | | | | AMD Am29000, Texas Instruments OMAP | Microsoft Windows, Linux, FreeBSD, Plan 9, OS X, Solaris, Irix, UnixWare, HP-UX, Internet Explorer |
| FreeRTOS | | | | | | | | | | | | | | | | | | | | | AVR, PIC, MSP430, HCS12, 8052, MicroBlaze, Cortex-M3, H8S | |
| eCos | | | | | | | | | | | | | | | | | | | | | , ColdFire, FR-V, h8, , Nios II, | Microsoft Windows, Linux |
| RTEMS | | | Xen | | | | | | | | | | | | | | | | | | Blackfin, Nios II, Coldfire, Texas Instruments C3x/C4x, H8S | Linux, Solaris, Cygwin, FreeBSD, multiple CPU simulators |
| HelenOS | | | | | | | | | | | | | | | | | | | | | | |
| E/OS | | | | | | | | | | | | | | | | | | | | | | |
| TempleOS | | | | | | | | | | | | | | | | | | | | | | QEMU, VirtualBox, etc. |
| Name | x86, i386, IA-32 | x86 SMP | Xen | IA-64 | x86-64 | PowerPC | PowerPC SMP | SPARC32 | SPARC SMP | Alpha | MIPS | ARM | XScale | M68k | PA-RISC | OpenRISC | Elbrus | LoongArch | SuperH | z/Architecture | other | hosted mode |