I recently bought a new netbook (Samsung NC10) for taking on the train when I go to London, Birmingham etc. for meetings. So far it’s been an excellent buy, except that the battery life has been nowhere near the five hours quoted in the literature and I’ve only managed to get less than two hours constant running.
At first I couldn’t understand why this was happening, until I realised that Ubuntu automatically starts bluetooth when I boot the machine, and this drains the battery. I never use bluetooth, so I tried to disable it permanently. However, whilst the preferences panel allows you to disable bluetooth for the current session, it will still start automatically when you reboot. There’s an option to disable bluetooth on startup, but this only applies to the panel applet and doesn’t actually stop the bluetooth service from running.
After a bit of searching I discovered a program called Boot-up Manager, which can be installed through the standard repositories—it is the ‘bum’ package (stop sniggering at the back!). Start this up after installation and uncheck the ‘activate’ checkbox next to bluetooth, and the next time you start your machine it will be disabled. You can still start the service manually through the panel applet, should you need bluetooth for a single session.