I'm thinking about getting an external hard drive unit for my home use. We have 3 PC's running XP and my Mac. I have looked and some if not most work on PC or Mac os. Can I back up and store files for both PC and Mac on the same unit?
If you format the drive to FAT (known as MS-DOS format in Disk Utility) then yes, both Mac and Windows will be able to read/write to this drive. However, your files will be limited to 4 GB in size.