FATtiedostojärjestelmä

FATtiedostojärjestelmä, often referred to simply as FAT, is a family of file systems developed by Microsoft. Its origins trace back to the early days of personal computing, and it has been a dominant force for removable media and older operating systems. The name FAT stands for File Allocation Table, which is the core data structure used by the file system to manage files on a disk. This table tracks which clusters (contiguous blocks of disk space) are allocated to each file.

There have been several versions of FAT, each introducing improvements. FAT12, FAT16, and FAT32 are the most well-known. FAT12 was used in early MS-DOS systems and had a very limited capacity. FAT16 offered larger file and partition sizes, becoming prevalent with MS-DOS and early Windows versions. FAT32, introduced with Windows 95 OSR2, significantly increased the maximum partition size and supported smaller cluster sizes, leading to more efficient use of space for smaller files.

Despite its widespread compatibility and simplicity, FAT has limitations. Its maximum file size is typically 4 GB (for FAT32), and it lacks advanced features found in modern file systems, such as journaling, file permissions, and compression. However, its ubiquity makes it an ideal choice for USB flash drives, SD cards, and other portable storage devices where cross-platform compatibility is crucial. Newer iterations like exFAT (Extended File Allocation Table) have been developed to address some of FAT32's limitations, particularly for flash memory devices.