All data volumes in a database instance are known collectively as the data area. The data area contains, amongst other things, the application data, the database catalog and the undo log entries of the database instance.
Concepts of the Database System, Volumes (Permanent Memory)
Database Manager GUI, Displaying Data Area Information
Database Manager CLI, show
Database Administration in CCMS: MaxDB, Monitoring the Data Area
Database Administration in CCMS: SAP liveCache Technology, Monitoring the Data Area