Most modern computers store the data and programs they are not immediately using on disks: magnetic disks, called hard disks or hard drives for those that are usually built in, or floppy disks, also known as diskettes, or just floppies, for those that are regularly inserted and removed; and optical disks, often called CDs (Compact Disks): CD-ROMs (Read Only Media), CD-Rs (Recordable), and CD-RWs (Read-Write). The device that accesses a disk for a computer is called a disk drive; a hard disk is usually built in to its hard drive, so those terms are often used interchangeably. This category contains programs for working with these disks: testing, checking, scanning, repairing errors, formatting, defragmenting, using different data storage formats, such as for different operating systems, and similar utilities.
Tools that examine a disk's physical sectors and file system structure for corruption. Sometimes partially corrupted data can be recovered, and affected sectors marked as bad, not to be used again.
There are different ways to organize computer data and program files on a disk, called file systems, or sometimes disk formats. While usually a given operating system only uses one main one at a time, it can often access several others. HPS, FAT, FAT32, NTFS and HPFS are some of the common file systems used on personal computers. This category contains utilities to enable one operating system to work with different file systems.
Partition management is the division of a disk into several different logical areas, that can usually be treated as separate virtual disks. Different disk partitions may be given different file systems, or compression levels. Using different operating systems on the same computer often involves creating different partitions for each. This category contains software to create and edit these disk partitions.
Utilities to show how the disk is being used, especially how files are taking space on a disk. These can provide graphical views, charts, or maps of disk space.