CentOS is a Linux distribution that attempts to provide a free, enterprise-class, community-supported computing platform.

Edubuntu is an official derivative of the Ubuntu operating system designed for use in classrooms inside schools, homes and communities.

FreeBSD is an operating system for a variety of platforms which focuses on features, speed, and stability.

Gentoo Linux is an computer operating system distribution

Kubuntu is an official flavour of the Ubuntu operating system which uses the KDE Plasma Desktop instead of the Unity graphical environment.

macOS is an operating system developed by Apple.

Debian is the open source and free Linux based operating system.

Fedora is an operating system based on the Linux kernel.

FreeDOS (formerly Free-DOS and PD-DOS) is a free operating system for IBM PC compatible computers. It intends to provide a complete DOS-compatible environment…

Haiku is a free and open-source operating system compatible with the now discontinued BeOS.

Linux Mint is a Linux based free operating system.

OpenBSD is a free and open source Unix-like computer operating system descended from Berkeley Software Distribution (BSD).