Solution:

What is a context diagram?

The context diagram is used to establish the context and boundaries of the system to be modeled:

which things are inside and outside of the system being modeled, and what is the relationship of the a system with these external entities.

A context diagram sometimes called a level 0 data-flow diagram, is drawn in order to define and clarify the boundaries of the software system.

It identifies the flows of information between the system and external entities. The entire software system is shown as a single process.

A possible context diagram for the Video-Rental LTD case study is shown below.

The process of establishing the analysis framework by drawing and reviewing the context diagram inevitably involves some initial discussions with users regarding problems with the existing system and the specific requirements for the new system.

These are formally documented along with any specific system requirements identified in previous studies.

Having agreed on the framework, a detailed investigation of the current system must be planned. This involves identifying how each of the areas included within the scope will be investigated.

This could be done by interviewing users, providing questionnaires to users or clients, studying the existing system documentation and procedures, observing, and so on.

Key users are identified and their specific roles in the investigation are agreed upon.