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Utility software helps maintain the system. Utility software includes:

• encryption software
• defragmentation software
• data compression software
• backup software

Encryption software

Encryption software disguises the contents of files so they can only be understood by authorised users. The software uses a complex algorithm to scramble the content so that it appears to be gibberish. Only authorised users can unscramble the content.

The software can encrypt specified files, or the whole of the hard disk on which the files are stored.

You can read more about encryption .

Defragmentation software

When a file is stored on a hard disk it is actually stored not as a whole file, but as a series of segments. Sometimes the segments run together in sequence (see File 1) and sometimes the segments are split up over a disk (see File 3). This is known as fragmentation.

Over time, more and more files become fragmented, as do individual files. A fragmented disk takes longer to read from and write to, making a computer run slower.

Defragmentation software takes the fragmented files and rearranges the segments so that they run contiguously. This decreases read/write time, thereby speeding up computer performance.

Data compression software

Compression software reduces the size of a file stored on secondary storage.

Smaller files are easier to transmit across a network as they require fewer packets to be sent. Their reduced size also means more files can be stored in any given area of storage.

You can read more about compression .

Backup software

Data can be lost accidentally, or deliberately. A user may accidentally delete or overwrite a file, or a hard disk may fail, preventing access to any files stored on it. A hacker or malicious user may deliberately delete or overwrite data.

To prevent data loss, regular copies of the data should be made. A copy of data is known as a backup. Backups can contain a copy of all files on a computer, or just ones specified by a user.

Network managers make regular backups of all files on a network using backup software. The software automatically makes a backup at a scheduled time of day, usually during the evening when the network is quiet. Backups are usually made to a high capacity secondary storage device, or to the cloud.

If data loss occurs, data can be retrieved from the backup. The software allows all backed-up files to be retrieved or just specified files.

Two types of backup are possible:

• full backup
• incremental backup

A full backup involves making a copy of every file on the computer or network. They can require a lot of storage space and can be time consuming to make.

Incremental backups take a copy of any new files created since the last backup, or of any files that have been edited, such as user documents.

Most network managers make an initial full backup and then switch to daily incremental backups. This way all data is backed up and daily backups are small and less time-consuming.