Good luck writing a driver for a proprietary UMD Drive. The biggest problem is getting all the information about it to properly write such a driver. This is the same issue people have with Drivers for ATi Graphics Cards in Linux.

BTW: Who the hell is going to buy another PSP just so they can tear out the UMD drive from it to hook it up to the PC, and it's not even like there's a PSP emulator for the PC so it's completely useless outside of the idea that you can somehow exploit games. Which is already being done with GTA:LCS