The Computers: Software: Operating Systems: (Open Source Operating Systems )

This section lists operating systems (OSs) based on open source code. Some such OSs have closed source variants (BeOS, DOS, Unix, VMS), or straddle these two licensing models (QNX). Open Source computer programs (OSs are programs) are those that include source code, and-or for which the source code is freely available, or made available without a fee or limited permissions. On this page, OSs are arranged in three groups and levels: 1) Top group: types or classes of OS. 2) Middle group: OSs for which there are more than one instance of an OS of this name-type, an OS family. 3) Bottom group: specific OSs, individual instances; there is only one OS of this name-type. Open Source Operating Systems Software Computers.

Open-source software ( OSS ) is computer software with its source code made available with a license in which the copyright holder provides the rights to study, change, and distribute the software to anyone and for any purpose. (wikipedia)