As LCGuy has already pointed out, the sizes of HDDs in older Macs are software-limited, by the System. By the time of OS 9 the theoretical limit was 2TB, but the ability to address the possible number of blocks did not always keep pace with the appetite until 48-bit LBA (logical block-addressing) arrived in the ROM-in-RAM v10.2.1 of OS 9.2.2 for the G4/MDDs. Then the foot was on the other boot, because there were not yet drives as big as there was room to address. So the short answer is, no in your Mac, but yes in an external FireWire drive attached to your Mac. FireWire doesn't believe in restrictions. (It's a free soul.) All you need to do is get your FireWire connection, but it will, of course, be FireWire 400. However, that is no slouch at transfer, and with the right Oxford chip, will also be bootable if there is a (bootable) System installed on the external drive.
1TB will be a lot to back-up, and necessitate another external FireWire drive. One of the external drives will need two FireWire ports for the daisy-chaining, or the FireWire card in the Mac will need to have two ports. Time taken by disk housekeeping operations will bemore than tiresome, as UnknownK suggests.
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