= FAT = FAT is a simple non-Unix-like disk-based file system originally designed for the MS-DOS operating system and supported by HelenOS. The file system comes in several flavors, each with different limitations. The FAT16 was the second file-system supported by HelenOS and the first one to need an underlying block device. The original FAT16 server was created in 2008 by Jakub Jermar. In 2011, the GSoC student Oleg Romanenko added support for the other two variants: FAT12 and FAT32. Oleg also implemented support for the long file name extension (LFN), defeating thus the greatest limitation of this file system, which is the 8.3 file naming scheme.