depends what you mean by the term "back-up".
you *can* "back-up" your copy of Winzip or WinRAR (software) that you purchase, but you would still have to re-install it, after installing your new hard drive (.. assuming a clean installation of Windows with no Ghost backup).
tho this is unnecessary, cuz you could just download a new, updated copy from the manufacturer's web site.
so i think this is what you are referring to when you mention not being able to "backup software".
in its most generic sense, a backup is simply duplicating files .. in case something happens to the originals.
"mirroring" is a specific term that is sometimes used generally, and I'm not sure of the context in which you're using it.
'mirroring' as I understand it, is usually a feature RAID hardware, where you reproduce instantly the contents of one drive on another.
http://en.wikipedia.org/wiki/Disk_mirroring[ notice that RAID is Rad with an 'i' added. =) ]
ghost simply takes all the contents of the drive you select, bundles them all into a single compressed file, and writes that file to where you instruct it to.
this might provide some insight or clarification:
http://clone.radified.com/or maybe this page:
http://ghost.radified.com/ghost_intro.htmmost importantly you need to understand this:
http://ghost.radified.com/ghost_caveat.htm