Games like Xak are "on sector", so the disks contain no files so you cannot extract them to play the game. You can however use Runit to play theses games and actually save.
And if you don't want to use a user disk, you can also save to SRAM on an (FM)PAC. And you can save from SRAM to disk (or SD), so that also should work. Then you also have small save files. Besides Runit also other programs like hdemu should be able to let you save to diskimage.
