FAT32

FAT32 (a variety of FAT, which stands for File Allocation Table) is a simple filesystem with limited capabilities. Although the Intellectual Property Rights belong to Microsoft, the format specifications are made available publicly. Nowadays the FAT32 filesystem is mostly used on portable devices such as thumbdrives, external hard drives and SD cards.

Resources

 * Microsoft EFI FAT32 File System Specification
 * Wikipedia - FAT32