[JMPIX]

i dont know what formatting means...I have just purchased a USB 250GB LaCie Porsche harddrive and also a 120 GB firewire one of teh same design. Do I need to format the drives or do I just plug them in and copy all my files on to them... not formatting has seemed to work ok on my last external hard drive... but someone told me i should format the drives for my mac?
thanks

[Timetheus]

I don't know that you need to format the drives, but I would just to ensure that all data is properly erased and the drives are in the Mac OS extended file system (Mac OS X's native File system, though it can also read/write the older Window's FAT32 and read the somewhat newer Windows XP's NTFS)

To do so, open your applications folder, followed by your Utilities folder and launch the "disk utility" in that folder (It comes with OS X). Make sure your externals are connected and select them in the list on the left (If I remember right they'll be named "Firewire HD" by default).

In the top center of the screen select the "erase" tab. Below this select "Mac OS X extended (Journaled)" and type a name for your drive (If you want). Than just click "Erase" near the bottom. Disk Utility does the rest, and after it finishes your drives are good to go.

[osiris24x]

Drives need to be partitioned and formatted for the correct filesystem, in order to function properly. The Mac is able to read/write FAT32 drives (these are MS Windows drives) so it isn't necessary, but it is strongly recommended. Using the method that Timetheus laid out above, I recommend you always initialize a new drive, before use.