Backup Types:

Full Backup - All data files are backed up, regardless of the status of the file archive flag.  The archive flag is cleared after the backup.  A full backup takes the longest time to run and creates the largest backups.  Restoring a full backup requires only the latest full backup file or tape.

Incremental Backup - Only data files that have changed since the last incremental backup based on the state of the archive flag are backed up.  The archive flag is cleared after the backup.  This is the quickest running backup type and it creates the smallest backup files.  However, to restore an incremental backup requires the longest time.  You must first restore the latest full backup, then restore every incremental backup since then in the proper order.

Differential Backups - This type is a compromise between the a full backup and an incremental backup.  It backs up all data files since the last full backup based on the status of the file archive flag.  However, it does not clear the archive flag when done.  To restore a differential backup requires you first restore the latest full backup and then the latest differential backup.