No. FireWire does not charge or transfer music and data when your Mac is asleep or turned off. To prevent your computer from going to sleep, you can set your Energy Saver preferences to "never sleep." Or you can purchase a self-powered FireWire hub, which will allow you to charge and transfer music from your computer all the time, even when it's asleep. You can use the FireWire cable with the included power adapter to charge iPod without your computer.