Summary Checklist

• Views are usually too complex to be understood all at once. Chunking information helps convey it more effectively. View packets are the documentation units that chunk view information.
• View packets are related to one another by child-parent relationships, which correspond to zooming in and out, and sibling relationships, which correspond to panning to different areas of the system.
• Because systems almost always exhibit multiple styles, view packets in different views can be parents, children, or siblings.
• Refinement, the gradual disclosure of more detailed information, is another chunking mechanism. Decomposition refinement reveals internal substructure. Implementation refinement replaces elements with different elements showing an implementation.
• Views can exhibit descriptive completeness. Descriptively complete views show all elements and relations; views that are not descriptively complete suppress some elements and relations.
• A context diagram shows what's in and what's out of the system under consideration and the external entities with which the system interacts. A pure context diagram shows no internal structure, but in practice, many do.
• A system does not show a single top-level context diagram, but rather one in each view. Each such diagram shows the interactions with the environment in the vocabulary for that view. All show what's in and what's out.
• Other context diagrams are used to establish the scope of a view packet.
• Combining views often yields useful insights about the architecture, when the combination is carefully considered. A combined view comes about either as a hybrid style or an overlay.
• Views with a high correspondence are good candidates for combining.
• Document variability and dynamism using the same styles you normally would choose for that architecture. Show what's constant and what's not. For the latter, describe the range of options and when the option is bound.
• To document a new style, write a style guide. Include vocabulary, semantics, analyses, and implementation strategies.