I just bought an 8-in-1 and it appears as FOUR drives. Some slots are used for more than one format, since there are only 4 holes in the front, I guess it's one hole per drive
You shoudl be able to read and write to any card in any of the slots as a disk drive.
But it may not be possible to use more than one slot at a time.
Mine won't do CF and SD at the same time even though they are in different holes.