40 years later, X Window System is far more relevant than anyone could guess

Waylaid heading toward Wayland

The last official release of X, X11R7.7, arrived in June 2012. After a very long series of rights, licensing, and development debates, it has landed right where it is now: no plans for any future releases but still in use on Unix-like systems wherever its successor, Wayland, has not taken hold (or macOS isn't running).

Ars Technica's archives are full of pronouncements that, any day now, this or that distribution is going to leave X behind. As Evan Jenkins wrote 13 years ago:

X is the oldest lady at the dance, and she insists on dancing with everyone. X has millions of lines of source, but most of it was written long ago, when there were no GPUs, and no specialized transistors to do programmable shading or rotation and translation of vertexes. The hardware had no notion of oversampling and interpolation to reduce aliasing, nor was it capable of producing extremely precise color spaces. The time has come for the old lady to take a chair.

And yet, X is still something your Linux distribution might fall back to today in 2024 if graphics drivers have a hard time with Wayland. Ubuntu, having previously taken a shot at its own X replacement with Mir, switched to Wayland by default in 17.10 (Artful Aardvark), then back to X in 18.04 because of bugs, and only Wayland again in 21.04 in 2021. By then, most major distributions had landed on Wayland. But it will probably be quite some time until the last one does.

These days, a lot of astrophysics students and post-docs at Princeton are working on Mac computers; they get their hands dirty by interfacing with big Linux compute nodes (for which Lupton also wrote a beginner's guide). Lupton's X Windows guide was so old that he had trouble pinpointing a date on its creation. I tried a second time to ask him, in a slightly different, big-picture way, about X. Was he surprised, I asked, at how X was still something you could encounter on a computer, decades later?

"I'm not sure," he said. "It works. Maybe some people don't love how it works, but... I don't know, it's hard to think of why [it's still around]. It just is."