Unix System Laboratories. USL, which develops and markets the Unix System V operating system, the Tuxedo Enterprise Transaction Processing System and other standards-based system software products, started in 1991 as a subsidiary spun off from AT&T. Novell acquired USL in December 1992, partially as a counter to Microsoft and its Windows products. The announcement virtually set the stage for the next-generation operating system war. Novell, which is likely to better integrate NetWare servers with Unix, seeks to achieve three goals: expand its market share, reduce its losses to Windows NT, and accelerate the expansion of Unix, the low-end commercial market.