Parallels makes a big file under OS X and emulates the IDE interface to make the guest OS think it has a hard drive.
Darrell Spice, Jr. Trendy yet complex\nPeople seek me out - though they're not sure why\n[link|http://spiceware.org/gallery/ArtisticOverpass|Artistic Overpass] [link|http://www.spiceware.org/|SpiceWare]