* NetBSD: 8 in Tier I, another 49 in Tier 2, total of 57.
* Gentoo Linux: 10 to 12, as they target i[456]86 separately within IA-32
* Debian Linux: 11
* Fedora Linux: 4 primary, 7 secondary, total of 11
* L4: 9
* Red Hat EL: 8
* Ubuntu Linux: 8
* QNX OS: 8
* OpenSuSe Linux: 7
* Alpine Linux: 6
* CentOS (Linux): 5
* Illumos: 4
* Kali Linux: 4
* Q4OS (Linux): 4
* Android: 4
* Arch Linux: 1 official, 2 unofficial
* Parabola Linux: 3
* Slackware Linux: 3
* ChromeOS: 3
* QNX Neutrino RTOS: 2
* Haiku: 2, with 3 more ports underway
RiscOS runs across four or five generations of ARM.
Darwin used to run on three more platforms but newer versions don't.
Illumos is the kernel and libraries underlying OpenIndiana, Dyson, and many other systems based off the old OpenSolaris effort.
* NetBSD: 8 in Tier I, another 49 in Tier 2, total of 57.
* Gentoo Linux: 10 to 12, as they target i[456]86 separately within IA-32
* Debian Linux: 11
* Fedora Linux: 4 primary, 7 secondary, total of 11
* L4: 9
* Red Hat EL: 8
* Ubuntu Linux: 8
* QNX OS: 8
* OpenSuSe Linux: 7
* Alpine Linux: 6
* CentOS (Linux): 5
* Illumos: 4
* Kali Linux: 4
* Q4OS (Linux): 4
* Android: 4
* Arch Linux: 1 official, 2 unofficial
* Parabola Linux: 3
* Slackware Linux: 3
* ChromeOS: 3
* QNX Neutrino RTOS: 2
* Haiku: 2, with 3 more ports underway
RiscOS runs across four or five generations of ARM.
Darwin used to run on three more platforms but newer versions don't.
Illumos is the kernel and libraries underlying OpenIndiana, Dyson, and many other systems based off the old OpenSolaris effort.