(n.) Developed by Ken Thompson in 1969, the most popular general-purpose, multiuser operating system in the world. The coauthor is Dennis Ritchie, who created the C programming language. Unix became the first source-portable operating system in 1974 when it was implemented in C. Unix is the subject of an international standardization effort. It is a 32-bit system with excellent multitasking capabilities. Similar systems include Open Software Foundation (OSF), Version 7, Berkeley Software Distribution (BSD), Xenix, Ultrix, Linux, and GNU. Unix is a trademark, owned originally by AT&T, sold to Novell in 1993, and subsequently to Santa Cruz Operation, Inc. (SCO) in 1996. In 1993, Novell assigned the rights to the Unix name to X/Open Company Ltd., and they license it worldwide.