I love DexDrive and have one for both PSX and N64. They work like any other disk drive. You run the program that comes with it, put a card in, and you can backup or restore save files to and from your hard drive or a computer disk. You can even e-mail save files with your frineds, which is great for created characters, teams, or plays in sports games. I really wish they'd put one out for Dreamcast. I think 15 is plenty for a PSX memory card since most games only take one save slot. It's a hell of a lot more than an N64 controller pack lets you save. I hate VMUs though. They don't seem to hold much, and the batteries in them die constantly. When I decide to get NBA 2K1, I'll have to get two more VMUs (at $20 each at the cheapest) just so I can play full seasons in NFL 2K1 and NBA 2K1.