I'm traveling for work today, so I'm working on a train. That's mobile computing, isn't it? Some trains have really nice tables and plenty of power outlets. I remember when airplanes used to have working power outlets on the seats. Now, those green lights are never on.
So, have you ever computed on a train? It can be a bit bumpy at times, so I often wonder what my laptop hard drive is going through. If you do a lot of computing on the train, you should probably get an SSD (solid state disk) in your mobile computer. SSDs are dropping in price (they're still expensive), but it's a worthwhile investment if you're constantly working on trains.