i want to know whats a good external hard drive do i need a specific one for my emac specs 1.42ghz 1gb ram 80gb hd
I recommend a 2.5" s-ata hard drive enclosure, because they are bus powered, meaning it will not require an external power supply, as long as it is connected to USB2, or the six pin FW 400. If it has just the four pin FW going into the drive, it will not have bus power. Another advantage to one of these, is the drive will power on and off with your Mac, but it will stay on when the Mac is sleeping, if it is USB.
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Yes true that you wouldn't need a power supply but desktop hard drives are always country miles in front of laptop hard drives speed wise.