USENIX celebrates its 50th anniversary in 2025. We celebrate decades of innovations, experiments, and gatherings of the advanced computing system community. And in the spirit of our ever-evolving community, field, and industry, we announce the bittersweet conclusion of our longest-running event, the USENIX Annual Technical Conference in July 2025, following USENIX ATC ’25.

Since USENIX’s inception in 1975, it has been a key gathering place for innovators in the advanced computing systems community. The early days of meetings evolved into the two annual conferences, the USENIX Summer and Winter Conferences, which in 1995 merged into the single Annual Technical Conference that has continued to evolve and serve thousands of our constituents for 30 years.

For the past two decades, as more USENIX conferences have joined the USENIX calendar by focusing on specific topics that grew out of ATC itself, attendance at ATC has steadily decreased to the point where there is no longer a critical mass of researchers and practitioners joining us. Thus, after many years of experiments to adapt this conference to the ever-changing tech landscape and community, the USENIX Board of Directors has made the difficult decision to sunset USENIX ATC.

USENIX ATC in its many iterations has been the home of an incredible list of “firsts” in our industry:

• In 1979, ONYX, the first attempt at genuine UNIX hardware, was announced.
• In 1982, DEC unveiled the creation of its UNIX product.
• In 1983, Eric Allman presented the first paper on Sendmail, “Mail Systems and Addressing in 4.2BSD.”
• In 1985, Sun Microsystems presented the first paper on NFS, “Design and Implementation of the Sun Network Filesystem.”
• In 1988, the first light on Kerberos and the X Window system was presented.
• In 1989, Tom Christiansen made his first Perl presentation as an Invited Talk.
• In 1990, John Ousterhout presented Tcl.
• In 1995, the first talk on Oak (later JAVA) was given as a Work-in-Progress report.
• In 1998, Miguel de Icaza presented “The GNOME Desktop Environment.”

These examples represent just a few of the many contributions presented at USENIX ATC over the years, with hundreds of papers that account for thousands of citations of work that the community has presented, discussed, learned from, and built upon as the community evolved.

Part of that evolution involved the continued development of subcommunities, as has been the case with USENIX Security, which began as a workshop in 1988 and has since grown to an annual symposium and the largest of our events in terms of both papers published and number of attendees annually, with 417 papers and 1,015 attendees at USENIX Security ’24. The LISA (Large Installation System Administration) Conference, which also started as a workshop in 1987, grew in a similar fashion to its peak of over 1,000 attendees, but like USENIX ATC declined as its community changed until its own sunset in 2021.

Papers on file and storage systems that would have previously been presented at USENIX ATC in the early 2000s began to find homes at FAST when it was founded in 2002. Networked systems papers started flowing to NSDI in 2003. As the biennial OSDI continued to grow alongside ACM’s SOSP, OSDI became annual in 2021 and SOSP followed suit, providing the community with additional venues. While landmark moments in our community have continued at USENIX ATC, many others have also occurred at these other USENIX conferences, as showcased in the USENIX Test of Time Awards and the ACM SIGOPS Hall of Fame Awards, which celebrate influential works presented at both SOSP and OSDI. Although numerous papers continue to be submitted to USENIX ATC with significant research being reviewed, accepted, and presented, the community has evolved, and now attends conferences other than USENIX ATC. From 1,698 attendees in San Diego in 2000, ATC attendance dwindled to 165 attendees in Santa Clara in 2024—even as we had over 4,000 people attend all USENIX conferences in 2024.

USENIX recognizes the pivotal role that USENIX ATC has played in the shaping of the Association itself as well as the lives and careers of its many attendees and members. We also realize that change is inevitable, and all good things must come to an end: if it weren’t for ATC being a “victim of its own great success”—a foundry of so many other successful conferences and workshops—USENIX would never have grown and expanded so much over the decades. Thus our hearts are heavy as we celebrate ATC’s history and legacy alongside the evolution of its younger siblings and face the financial realities of the post-pandemic world and volatile global economy. USENIX’s resources to support its conferences and communities are not unlimited, particularly as we maintain our commitment to open-access publications that are free for our authors to publish. We have been reporting about these challenges via our Annual Meeting and subsequent reports for the past several years (2024, 2023, 2022, 2021, 2020). We deeply appreciate the financial support we have received from our community in the form of donations, memberships, and conference registrations. However, we continue to operate at a deficit and ATC continues to shrink. In making this hard choice, accepting the reality in front of us that encourages us to innovate in a different direction under challenging circumstances, we seek to embody the values of this community that was founded on curiosity, persistence, and collaboration.

As we celebrate 50 years of both USENIX and ATC in its varying forms, we look towards the future of this vibrant community in the form of the many conferences that ATC continues to help create in its image: welcoming, thoughtful environments for the presentation of innovative work that fellow conference attendees help push forward. We look forward to honoring ATC’s legacy alongside USENIX’s history and its future in Boston in July of 2025.

We would love to hear memories of your experience at the USENIX Annual Technical Conference over the years. Please submit your thoughts in words, video, or both by Monday, June 2. We will share your memories both at USENIX ATC ’25 and afterwards. We hope that you will join us at USENIX ATC ’25, which will include both a celebration of USENIX’s 50th anniversary on the evening of Monday, July 7, and a tribute to USENIX ATC on the evening of Tuesday, July 8.