That's fine. I was just wanting to make sure you weren't in any danger of bricking your device if you had installed a bunch of apps from testing and devel.

You stated you had installed a lot of apps. If you're dabbling in testing and devel you need to be careful, but otherwise you should be fine.

78% is pretty close to normal. Sounds like you may have mplayer installed or something.

If you reboot the machine and do another df it will probably drop a couple of percent. This is because there is a bug that exists where space on the root partition (that's the "/" I was telling you about) isn't cleaned out after installing things. It gets cleared during a restart.