Well, among other things -- the CPU in the Pi is ARMv6 with a hardware FPU. Until the Pi came along, most people compiled either for ARMv6 with no FPU or for A

Well, among other things -- the CPU in the Pi is ARMv6 with a hardware FPU. Until the Pi came along, most people compiled either for ARMv6 with no FPU or for ARMv7, so at the beginning you had to compile your own packages if you wanted reasonable performance. Also, the Pi limits power draw to something like 100 mA; if you just plugged in a USB Hard Drive it'd more than likely shut down the entire board (especially in rev1). So you'd need to put a powered hub in the middle...