 The versions leading to v7 are also sometime called Ancient unix.After the release of Version 10, the Unix research team at Bell Labs turned its focus to Plan 9 from Bell Labs, a distinct operating system that was first released to the public in 1993.Each of the systems in this list is evolved from the version before, with Unix System III evolving from both the UNIX Time-Sharing System v7 and the descendants of the UNIX Time-Sharing System v6.