Too bad they didn't continue its development. Probably choosing a different GUI than TK would have helped to spark more people's interest in the project. There's a huge need for an alternative OS on Android phones, but most of the people who would benefit from it don't know that, so that need doesn't translate to actual demand.

I don't see Tk as being a problem. Rio, however, and the continued reliance upon 3-button mice, dates both Plan9 and Inferno and makes it quite hard to use them on laptops with trackpads.

what's wrong with three button mice? virtualy all pc's outwith macs that use mac mice use three button mouse's

Emulating three buttons on a trackpad (or touchscreen) is hard to do right. I don’t use mice on my laptops.

ah I see what you mean I mostly used desktops hadn't thought about ipads and the like

What's wrong with Tk, exactly?

Everything and nothing, depending if you're a hacker or a common user.

Actually, it's pretty bad for both. It's both ugly (which users hate) and a pain to develop for if you want to do anything slightly unconventional.

The pain of developing it was one reason I didn't do much with Hellaphone after that summer. Other reasons: lack of funding and no spare phone to use if I wanted to develop it on my own time.