Hello, I am extremely new to the Mac World and I recently got a used Power PC G5 with a 1.9 GHz; 1GB DD2 SDRAM (if that means anything). Additionally, I picked up a Western Digital 750 GB external HD which had been used with a PC XP configuration. My Mac OSX (Ver. 10.4.11) won't read the Western Digital (WD); so I'm trying to "reformat" it to accept Mac video for editing purposes (storing completed iMovie projects right now and raw video footage); I ran across these options in the Utility; "Mirror Raid"; "Striped Raid" or "Concatenated Disk Set". Which should I chose and what can I do to install this WD to fit my needs? Can anyone out there help me or direct me to some help? Thanks, Larry If anyone has ANY answers (before I click and screw up my external HD or my MAC--PLEASE e-mail me at "email@example.com". I will be most appreciative. Take care.