Wikipedia
The USENIX Association is the Advanced Computing Systems Association. It was founded in 1975 under the name "Unix Users Group," focusing primarily on the study and development of Unix and similar systems. In June 1977, a lawyer from AT&T Corporation informed the group that they could not use the word UNIX as it was a trademark of Western Electric (the manufacturing arm of AT&T until 1995), which led to the change of name to USENIX. It has since grown into a respected organization among practitioners, developers, and researchers of computer operating systems more generally. Since its founding, it has published a technical journal entitled ;login:.
USENIX was started as a technical organization. As commercial interest grew, a number of separate groups started in parallel, most notably the Software Tools Users Group (STUG), a technical adjunct for Unix-like tools and interface on non-Unix operating systems, and /usr/group, a commercially oriented user group.
USENIX has a special interest group for system administrators, LISA, formerly SAGE.
It sponsors several conferences and workshops each year, most notably the USENIX Symposium on Operating Systems Design and Implementation (OSDI), the USENIX Symposium on Networked Systems Design and Implementation (NSDI), the USENIX Annual Technical Conference, the USENIX Security Symposium, the USENIX Conference on File and Storage Technologies (FAST), and with LISA (formerly SAGE), the Large Installation System Administration Conference (LISA).
USENIX's founding President was Lou Katz.