NTbackup - Backup Types

Normal
Backs up selected files, and mark each file as backed up.

Copy
Backs up selected filed, but doen not mark any as backed up.

Incremental
Backs up selected files only if they were created or modified since the previous backup.

Differential
Backs up selected filed only if they were created or modified since the previous backup, but does not mark them as backed up.

Dialy
Backs up only files that were created or modified today.