The file system, File System ( FS), is a component of the operating system and forms the interface between it and the drives. It determines how the computer names, stores, organizes and manages files on the disks. A file system consists of files, directories and addresses through which files are located. The top- level root directory of a file system is the root directory.
The file systems of most operating systems are incompatible with each other; however, there are operating systems that support multiple file systems. Thus the File Allocation Table( FAT), the file system for the DOS operating system, which works in the version FAT16 with a 16-bit addressing and can administer a data quantity of up to 4 GB. The successor version FAT32 is used in Linux, Windows 95, 98 and Windows NT and can manage up to 2 terabytes( TB). And in Extended File Allocation Table( exFAT) with an address space of 64 bits works. This allows file sizes of up to 512 terabytes (TB) to be managed.
In addition, there is the New Technology File System( NTFS) for Windows NT, the High Performance File System( HPFS) from IBM for OS/2, Windows NT and Linux, the Journaling File System (JFS) from IBM for AIX, the Extended Secondary File System (EXT2 and EXT3) for Linux, for Windows 8 the Resilient File System( ReFS) and some more. For Apple's MacIntosh there are two standard file systems with the Hierarchical File System( HFS+ and the further development HFS+, which work with smaller allocation units compared to File Allocation Table (FAT) and can access the partitions faster.
File systems differ in security features, multi- user capabilities and effective use of storage space. For example, some operate with journaling to ensure data consistency. For compact discs( CD) and DVDs, the ISO 9660 file system has become established.