I'm using a Mac Pro (early 2009) which has 4 Firewire ports. Today I connected two Firewire Compact Flash readers. The first CF card mounted properly. When I put the second CF card in the second Firewire CF reader it caused both readers to crash. Does anyone know what the problem is? Why is it not possible to connect two Firewire devices to two ports of the Mac Pro at the same time?