You cannot push to anything external from the camera (unless you have the wifi accessory). A computer with the proper drivers can pull images from the camera. They are available for PC's and Macs.Canon cameras do not write to a USB Hard drive thru their USB port, if thats what you were asking about. The 1D X has a network port, so if you have a self powered drive with a network connection, that would work.
That is what I was thinking. Well they transfer to a external drive or does it have to have a computer?