People are talking about trying to power and charge the Surface devices from a slave USB connection the way cell phones work. However, cell phones do not have their own host USB port for connecting other USB devices -- that want to be powered from the host
device (the Surface).
So let's say the Surface could be powered from a slave USB connector. Does that mean I should be able to power one Surface by connecting its slave USB connector to the host USB connector of another Surface, that in turn is being powered from its slave USB
connector?
The USB specification limits how much power can be drawn across the USB connection. If a Surface is going to supply maximum power to a peripheral plugged into its host USB connector, obviously its going to need to draw more than that amount of power from
its own power connection. If that power connection is USB, it cannot do that without exceeding the USB specification. (And USB power supplies are not designed with the expectation of the device exceeding the USB specification.)
The underlying point is the Surface is not like small devices like MP3 players and cell phones -- and one reason among several is because those devices do not support having USB peripherals plugged into them. The iPad doesn't even support USB peripherals
being plugged into it.
The question is, how many products exist that can be powered from a USB connection that will also host and power USB peripherals beyond just mere flash drives? How many tablets on the market can be powered from USB while also supporting a keyboard? Joystick?
External hard drive? Host powered USB hub with a multi-card flash reader/writer accessing multiple flash memory devices simultaneously?
I too would "prefer" my Surface to be able to work from USB power just like my Windows Phone. However I understand the limitations it would have placed on the device, and that my Surface is not just a tablet but also a replacement for my notebook computer
that never supported being powered from USB.