I was looking at this Dimension that had the Dell Data Safe as an option. According to the explanation the DDS consisted of a Raid drive mirroring your primary HD and also uses Norton Ghose to backup updated files on to a partion on your primary HD.

Is this typical of a raid? Isn't just mirroring the HD on the raid drive enough? What software is used to retrieve a file from the raid drive or the Ghost partition?

The option was quoted as either an 80 or 160gb option. When they say 80gb, is that the total for both the drives (meaning you have less than 80gb of storage because of all the duplicate files) or does that 80 mean that's what's on each drive?