I think Moto's right - some laptops had external drives that connected to the printer port. I've got an old Omnibook 6000 that works like that.
Dunno about 5 1/4" drives on the Amiga, but 3,5" ones are all host powered and it looks like that combo has a fuse on the back. Is that an external power cord or the D-Sub cable? If that's a power cord, one port connects to the PC's printer port, the other to the printer - no way this is an Amiga drive.
I dimly remember that Schneider/Amstrad computers sometimes had external drives that were pretty much set up like that.
Ah yes: you can open the 3,5" drive's front lid a bit: if there are two sensors on the right side, it's a HD floppy.
