The OS uses applications called utilities which allow the user to manage the computer. There are many different utility programs and they may vary across operating systems. They are often accessed via a special menu or control panel in the OS.
Backup - This allows the user to restore the system to a previous state which is saved as a backup. This is only usually used if a system malfunctions.
Disk cleaner - The storage drive is divided into a number of clusters. The table of contents serves as an address book, keeping a record of each file and the clusters used to store that file. When a file is deleted, the address to the location on the disk is removed.
Disk defragmentation - When files are deleted, unused clusters become available for reuse. These can end up being distributed across a drive, especially if the original files were small. If a large file is then written to a drive, its data could be spread across different clusters leading to file fragmentation. Defragmentation involves rearranging the information on a disk so that files appear in continuous sequences of clusters. This will improve file access times. Most modern operating systems run this process automatically.
Formatting - Storage drives need to be formatted to be compatible with an OS. The OS usually formats storage media when it is connected to the computer. It is often the case that a storage drive cannot be compatible with both Windows and Mac OS X.
user accounts - allow the user to allocate specific users and protects personal files and programs from unauthorised access.
encryption - can encrypt data when it is stored, or whenever it is transmitted over a network.