Novell's implementation of Unix System 5 heavily based on Release 4.2 but with enhancements and new bundled products. In 1993 Novell acquired Unix Systems Laboratories from AT&T along with the Unix trademark. UnixWare was the result of Novell's efforts to make Unix interoperable with Novell NetWare. In 1995 Novell sold UnixWare and the rights to the Unix operating system to SCO at a time when UnixWare was gainnig popularity. It was later the first 64-bit operating system on the Intel platform, and, in 1999, is the world's fastest-growing commercial operating system.