Beginning to write a Software Requirements Specification (SRS) is a daunting process. As you start elicitation and move onward through the requirements cycle, you should plan your approach and begin writing as soon as possible. In this module, we discuss local and global rules that should be followed to lead to success.

Within a requirements document, you should tell a story. Pictures help in stories! In this lesson, we'll look into some of the "pictures" that you can create to clarify understanding for all readers and to help yourself know that all points are being covered clearly and completely. Specifically, we'll consider high, system-scope diagrams.

At a lower level, Entity Relationship Diagrams, Data Flow Diagrams, and SADT diagrams can be used. All three sets of diagrams work together to explain lower-level relationships and dataflow for components in the system-to-be. In this lesson, we'll discuss what these diagrams look like and what information should be included in such diagrams.

System level diagram and low level diagrams work together. Each low level diagram also relates to other low level diagrams. In addition to these diagrams, we also have diagrams to explain events.

All diagrams created for a SRS document must link together, in addition to being linked to and explained in the text. In this lesson, we consider inter-view relationships between diagrams and how the combination of multiple diagrams assists in analysis of our system view and explanation. We also talk briefly about a more formal format of requirements writing for mission critical and safety critical systems. Lastly, we discuss using diagrams to correspond with text in the SRS document- remember: you're telling a story!