EXT2 (Extended File System 2 or Second Extended File System) is the default file system for most Linux distributions. FAT32 (File Allocation Table - 32 bit) and NTFS (New Technology File System) are used in Windows environments, and HFS+ (Hierarchical File System Plus) is used by Mac OSX.
The ext2 or second extended filesystem is a file system for the Linux kernel. It was initially designed by Rémy Card as a replacement for the extended file system (ext). Having been designed according to the same principles as the Berkeley Fast File System from BSD, it was the first commercial-grade filesystem for Linux.
The canonical implementation of ext2 is the "ext2fs" filesystem driver in the Linux kernel. Other implementations (of varying quality and completeness) exist …