Errata

The Backup process types are explained the wrong way round. The Incremental backup process is describing the Differential backup process and vice versa. The Incremantal backup contains only new changes to the data since the last Full or Incremental backup and the restore requires the last Full backup along with subsequent Incremental backups taken since the last Full backup (e.g. If three Incremental backups were taken since the last Full backup, the last Full backup along with all three Incremental backups are required to restore the data. The Incremental backups would need to be restored in the order they were taken). With the Incremental backup process, each Incremental backup is dependant upon the previous one because it only backups changes since the last Full or Incremental backup. On the other hand, the Differential backup contains all the changes since the last Full backup even if there were previous Differential backups taken. A Differential backup thus contains all the changes since the last Full backup and only the last Full backup and latest Differential backup is required to restore the data to the most recent state. Therefore, a Differential backup doesn't rely on any previous Differential backups because it has the same changes to data as these backups in addition to any new changes in data since the last Differential was taken.