Some free, open source computer operating systems include Ubuntu and FreeBSD. Ubuntu offers built-in firewall and virus protection, and as of December 2015, it is available in more than 40 languages.
Ubuntu is compatible with a wide range of free software, including Google Chrome, LibreOffice, Skype, Thunderbird and Gimp. It can run alongside other operating systems such as Windows and Mac OSX. As of 2015, computer manufacturers including Dell, HP and Lenovo let customers buy computers with Ubuntu installed.
FreeBSD is a UNIX-based operating system, and it can function as a server and a desktop operating system. It supports free applications such as Mozilla Firefox, LibreOffice and OpenOffice.