1. WP 2 Usability Attributes Affected by Software Architecture Deliverable D2 – Usability Patterns Presenter: Robert Chatley - ICSTM

2. Page 2 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Usability Patterns Techniques or mechanisms applied to design of software Address needs specified in terms of Usability Properties Applied at architectural design stage, not detailed design stage

3. Page 3 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Usability Pattern definition Name Description Relationship to software architecture Relationship to Usability Properties Example

4. Page 4 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Example Usability Pattern Name – Undo Description – The ability to undo an action and return to the previous state.

5. Page 5 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Relationship to Software Architecture Need component to record actions User and system actions need to be represented Details of previous state must also be recorded Component to reverse or replay actions

6. Page 6 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Relationship to Usability Properties Error Management - Correction –Users can undo an erroneous action Explicit User Control –Users feel more in control of the interaction

7. Page 7 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Another Example Name – Progress Indication Description – A mechanism to indicate how much of the current task is completed/remaining.

8. Page 8 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Relationship to Software Architecture Need component to model and monitor system tasks Send info on progress to UI Component generating progress indication must run concurrently with task

9. Page 9 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Relationship to Usability Properties Providing Feedback – User is provided with information about what the system is doing – Helps to plan tasks – User is reassured system has not “hung”

10. Page 10 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Example of Use Download progress in Internet Explorer

11. Page 11 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Applying a Pattern Context : designing a web browser Usability Property : provide feedback Pattern : progress indication

12. Page 12 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Architecture Before Display Network client Renderer Cache Controls

13. Page 13 © Status, 2002. CONFIDENTIAL First Review – June 17, 2002, Brussels D2 Usability Attributes Affected by Software Architecture Architecture After Display Network client Renderer Cache Controls Status display Progress monitor