Portage is a package management system originally created for and used by Gentoo Linux and also by Chrome OS, Sabayon, and Funtoo Linux among others. Portage is based on the concept of ports collections. Gentoo is sometimes referred to as a meta-distribution due to the extreme flexibility of Portage, which makes it operating-system-independent. The Gentoo/Alt project is concerned with using Portage to manage other operating systems, such as BSDs, Mac OS X and Solaris.