From what I've found on google, type A is the jack that is found on the controller (back of the computer). And type B is the type that is connected to a component (such as the scanner). We've mostly seen 2 types of these jacks, a smaller one (used for digital cameras and such - not sure what it's called). And this larger one called type B, which plugs into a scanner or another component. There's no B type on the computer itself, so the physical limitation of thumb drives is actually dependant on type A plugs, which is in the back of the computer itself
hence:
http://www.microwarehouse.co.uk/prod...px?SKU=DCA3746
hmm, why can't I find any firewire thumbdrives? FW plugs are smaller then USB