Back in 2013, the Ubuntu Edge project had photos of their mobile phone connecting to a dock that turned it into a full desktop machine. I’m not sure where to find those images, but here are a couple of nostalgic links to the old project that didn’t achieve the funding goals:
Shuttleworth MC’ed a video showing a few eye-candy examples of it in operation:
Here’s another where a guy at Canonical demoed Convergence in action:
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I’ve been enamored by the single computer device idea since then. I got pretty stoked when I saw the thing you saw about a Convergence station for the Librem 5. I had the wind taken out of my sails after trying to drum up some statistics about that item directly from Purism:
Spoiler alert, no, people didn’t think it was a wise idea, but all thumbs up on Convergence in the OS.