A. The USB port isn’t powered to support external devices such as hard drives. Low powered devices, such as USB lights normally require a USB A port (the type that flash drives use) whereas the USB port on the CDP-S100 is a different shape (B type port).
It may be possible to use an adapter to convert the USB port but this is something that you would need to research yourself as we don’t supply these. In theory, a low powered USB LED would work if a suitable adapter is used.