What is meant by an external interface in system design?

An external interface in system design refers to interactions that occur outside the proposed solution. This can involve communication between the system being developed and other systems, users, or external devices. Such interfaces are crucial because they define how a system will connect and communicate with the outside world, ensuring that it can effectively share data, accept user input, or interact with other applications.

For instance, an external interface might include APIs (Application Programming Interfaces) that allow different software systems to exchange information, user interfaces that allow users to interact with the system, or protocols that dictate how transactions between systems will take place. This aspect of system design is essential for ensuring that the system operates correctly within its environment and meets the needs of its users and other systems.

The other choices do not accurately capture the meaning of an external interface. Internal functions refer to operations within the system itself rather than its outward interactions. The method of storing data pertains to data management rather than interface design. Lastly, interfaces used only by the development team suggest a limited scope that does not encompass the broader interactions that an external interface would include.