So I like Plan 9 (the operating system—I haven’t seen the movie). I don’t really use Plan 9 all that often, but I would love to run a little cluster for fun. I was looking up the absolute cheapest way I could run an auth server, a file server, and a cpu server, and the first thing that came to mind are Single Board Computers (SBCs).

However, something like a Raspberry Pi seems overkill for this. All I need is a cpu, some ram, half a gig of disk to hold the OS, and two perhiperals—ethernet, and a serial connection. Something small.

So I was looking through small SBCs that have the bare minimum of components on them, and I realized that PoE is amazing. Imagine if this was a normal server or IoT device, and it could auto-config when it boots up. I could literally plug it in to ethernet, and I’m done. No other cables are needed! That dramatically decreases the number of cables I have to use. The switch is the power supply, too. That has to be why it’s so useful for stuff like security cameras—no need to bring power and data to the camera.

PoE in the right situation can be wildly useful.