In data flow diagrams, what does an open-ended rectangle represent?

In data flow diagrams (DFDs), an open-ended rectangle represents a Data Store or Warehouse. This symbol is used to signify a location where data is held for future use within the system. Data stores can represent physical databases, data repositories, or any other storage mechanism for data that the system requires to function effectively.

The open-ended rectangle visually distinguishes these data storage elements from other components in the DFD, such as processes, external entities, and data flows. By using this specific symbol, it becomes clear where data is being collected, maintained, and retrieved during the operations described in the diagram.

Understanding the representation of an open-ended rectangle as a Data Store is crucial since it helps delineate the architecture of the system and simplifies the identification of where data is managed and how it interacts with other parts of the system's processes.