Multi partition problems?

[longpanda]

In old Windows version (like Windows7 / Window 8...)  Only first partition can be mounted and used by user.
So if I set the 2nd partition as exfat partition to hold ISO files. How they put the ISO files into this partition?
They can't see the 2nd partition and use it at all.  After all, there are still a lot of people only using Windows 7/8/8.1 ...