Microsoft Disk Operating System (MS-DOS)
This file system originated from an operating system that Microsoft bought called QDOS, or the Quick and Dirty Operating System. Computers before Microsoft® Windows® operating system (OS) became available used this file system. While uncommon, it's still used in some places today.
FAT is an acronym for File Allocation Table. It was the standard format for floppy disks and hard drives all through the DOS years. FAT32 is the most common of the FAT file systems for Windows OS up to and including Windows® 8 operating system.
New Technology Files System (NTFS)
This is the newer and most often used file system. It's fully read and write compatible with current Windows and Mac® operating systems.