Sorry mate... bit late as usual but maybe it may help ya next time
What does the ATA100 mean and why do I want it?
ATA100 is the specification for the interface. As hard drives have got bigger and faster the interface starts to become a bottleneck and so the interface has been changed to keep the speeds up.
ATA100 supports 100Mbps data transfer.
ATA133 supports 133Mbps data transfer but its a relatively new interface and not many motherboards support it but it does connect to ATA100 interfaces.
I could tell you how good your Seagate drive is but I'll let your make up your own mind
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Fug