Unix System Laborotories, Inc.
After the lengthy anti-trust suit and the divestiture of the phone companies, AT&T was free of restraints imposed by decades of regulated monopoly. It was able to enter the computer industry and commercialize UNIX, a popular product of Bell Laboratories. UNIX System III, USL's first product, was released in 1982.
In 1989, AT&T re-organized itself and spun off its UNIX operations as a separate company, USO, the Unix Software Operation. In 1990, on the heels of the release of SVR4, USO became USL. USL, in charge of all UNIX source licensing, sued BSDi for copyright violations.
In 1992, USL was purchased by Novell, who moved to extricate the company from the lawsuit mess with the famous settlement that allowed BSDi, FreeBSD, and NetBSD to move forward.