System Context

Fig:SysCon shows the system context. A circle represents an external entity outside the software, the user in this case. A rectangle represents the software system itself (SWHS). Arrows are used to show the data flow between the system and its environment.

SWHS is mostly self-contained. The only external interaction is through the user interface. The responsibilities of the user and the system are as follows:

• User Responsibilities:
  • Provide the input data to the system, ensuring no errors in the data entry
  • Take care that consistent units are used for input variables
• SWHS Responsibilities:
  • Detect data type mismatch, such as a string of characters instead of a floating point number
  • Determine if the inputs satisfy the required physical and software constraints
  • Calculate the required outputs