FAT filesystems (msdos, vfat, umsdos) pertain to Microsoft systems. The simple msdos type supports the very primitive monocase variety in MS-DOS systems. For most modern Windows filesystems, you should use the vfat filesystem in order to get full access from Linux. The rarely used umsdos filesystem is peculiar to Linux. It supports Unix features such as symbolic links on top of an MS-DOS filesystem.
Any idea as to what that means?