Differential backup stores the data changes as they occurred since the last full backup. The procedure is similar to incremental backup, but differs in data storage. Thus, during the first differential backup, a full backup is performed. It forms the reference and is used for the comparison of the following differential backups. In the second backup, only the data that has changed since the full backup is saved. In the third backup, the changed data of the third backup is added to the data of the second backup, and so on.
The technique of differential backups requires less storage space compared to full backups and can be used for data recovery in a relatively short time.