1 Product Lines 1: Commonality Analysis CSSE 371 Software Requirements and Specification Mark Ardis, Rose-Hulman Institute November 1, 2004

2 Outline Motivation for product line approach Commonality analysis

3 Airbus Wins $4 Billion Order From Iberia, Beating Boeing (2/4/98 NY Times) Iberia ordered 76 planes:  9 A319’s, each with capacity for 124 passengers  36 A320’s, each with capacity for 150 passengers  31 A321’s, each with capacity for 185 passengers “Iberia president said single-aisle Airbus models... though differing in passenger capacity, had identical cockpits and mechanical specifications that offered savings in crew training and maintenance.”

4 Product Line Approach Reorganize the software development process  Evolve a family rather than build single systems  Invest in family infrastructure: Capitalize Develop systematic approach to building flexible application generators

5 Economics of Families Current Practice Number of Family Members Cumulative Cost Product Line Approach

6 Example Families Toyota automobiles and trucks IBM 360 computers Software?

7 Defining a Family: Commonality Analysis Dictionary: Technical vocabulary of the domain Commonalities: Assertions about every member of the family Variabilities: Assertions about variation across the family Parameters of Variation: Type and binding time of variabilities

8 Analysis Process Consensus process  All domain experts invited to participate  Led by a trained moderator  Real-time editing of the document

9 Commonality Analysis Exercise