I presume you're asking
where it could be downloaded from. I've never seen FDI or HDI images of the game anywhere.
I have the original game, and the seller was kind enough to supply a copy on 3.5" diskettes in addition to the original 5.25" disks, but the disk format is different and unreadable on a standard PC. There may be tools that let you do it though via low-level floppy disk access routines. I tried EditDisk and couldn't get it to work. (It may require PC98 hardware running Windows 95.)
If someone knows how to create a FDI file from a PC98 diskette using a standard PC floppy drive please share your knowledge! If not, kudos to anyone who uses their Google-fu and finds a good how-to site or walkthrough on doing it with some simple tool like EditDisk.