|Thanks for your input.|
When I run the TestDisk utility, it shows my Hammer 640GB external disk size as 2199 GB/2047 GiB but detects it properly as Hammer Morespace.
It prompts me to check HD jumper settings, BIOS detection, or installing patches for disk drivers if the size shown is incorrect.
However, I don't think the external drive has any jumpers, it doesn't show in my BIOS, and I couldn't find any driver patches for the same.
Any additional help would be great.