Kinds of File System in a Computer

Filesystems

• FAT DOS 6.x and Windows 9x-systems come with a defragmentation utility called Defrag. The DOS version is a limited version of Norton SpeedDisk.
• NTFS Windows 2000 and newer include an online defragmentation tool based on Diskeeper. NT 4 and below do not have built-in defragmentation utilities.
• ext2 uses an offline defragmenter called e2defrag, which does not work with its successor ext3, unless the ext3 filesystem is temporarily down-graded to ext2.
• JFS has a defragfs utility on IBM operating systems.
• HFS Plus in 1998 introduced a number of optimizations to the allocation algorithms in an attempt to defragment files while they're being accessed without a separate defragmenter.
• XFS provides an online defragmentation utility called xfs_fsr.