SCO OpenServer

SCO OpenServer (Xinuos OpenServer, OpenServer, SCO UNIX, SCO Open Desktop, SCO ODT) is a variant of UNIX originally released by SCO, and eventually becoming owned by Xinuos. Despite the "open" in its name, it has been closed-source, though somebody has edited its Wikipedia entry to say that it's become open-source (but that is tagged with "Citation needed"). It at one point used the DTFS filesystem (Desktop File System), but this is no longer supported; various other filesystems have been used with it.

Links

 * OpenServer
 * SCO/Xinuous official page