hard drive wont unmount

[chrisxkelley]

i have an 80gb hitachi hard drive that i have been using via external usb on my mac (10.4) for a while. i planned on moving it to my ubuntu server and wanted to format it. i used the disk utility to format it using the unix filesystem, but the linux pc doesnt recognize it. i went to format it to ms dos filesystem (fat i think), and the disk utility in os 10.4 tells me that it could not format because it couldnt unmount the disk.

any ideas, programs (win, mac or linux) that could help me, or websites that could tell me what to do would be greatly appreciated.

thanks a lot
chris