Product Line Engineering

CS 415, Software Engineering II

Mark Ardis, Rose-Hulman Institute

March 11, 2003

2

Acknowledgements

• David Weiss

• Lloyd Nakatani

• Janel Green

• Bob Olsen

• Paul Pontrelli

3

Outline

1. What is product line engineering?

2. How did we use product line engineering at Lucent?

3. Why did product line engineering work (at Lucent)?

4

Airbus Beats Boeing in Huge Jetliner Deal with USAir (11/6/96 NY Times)

• USAir, which had never bought a plane from Airbus, will purchase 120 Airbus A319s, A320s, and A321s...

• USAir’s current fleet is a hodgepodge of nine types of aircraft

• A simplified domestic fleet would allow USAir to lower costs.

• Importance of Commonality– USAir will reduce costs by using one aircraft type– Airbus is reducing its production costs by reusing one

aircraft type

5

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

6

Airbus Wins $4 Billion Order...

• “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.”

7

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

8

Application Environment

FAST: Family-oriented Abstraction, Specification, Translation

Domain Engineering

Application Engineering

Applications

Feedback

9

Domain Engineering

Application Environment

Domain Analysis

Domain Model

Domain Implementation

Analysis Document,Application Modeling

Language

Tools,Process

10

Application Engineering

Application Engineering

Application

Application EnvironmentApplicationRequirements

11

Economics of Families

CurrentPractice

Number of Family Members

Cumulative Cost Domain

Engineering

12

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

• Consensus process– All domain experts invited to participate– Led by a trained moderator– Real-time editing of the document

13

Application Engineering Environment

• A language for specifying family members

• Translators from specification to code• Libraries of common code • Supporting tools

– Simulator– Test case generator– Verifier

14

FAST Benefits

• Improved Understanding

• Shorter Intervals

• Lower Costs (Domain Dependent)

• Process Innovation

• Improved Technology

15

Cartoon of the Day

16

How Did We Use Product Line Engineering at Lucent?

17

Eli Whitney

• Born December 8, 1765• Raised on a farm in

rural Massachusetts• Attended Yale College

1789-1792• What did Whitney do in

1793?

18

The Cotton Gin

• Whitney invented the cotton gin in 1793

• Southern planters refused to pay royalties on patent– The gin was easy to

manufacture– Southern legislatures

conspired against Whitney

19

Eli Whitney

• Whitney’s company was out of business by 1797

• What did Whitney do in 1798?

20

Flintlock Components

21

Whitney’s Gamble on Automation

• Whitney offered to make 10,000 muskets in 2 years

• No other manufacturer had ever made more than a few hundred muskets

• Automation was needed to improve the efficiency of the locksmiths

• Whitney invented milling machines to produce interchangeable parts

• Demonstrated for Congress in 1802

22

Putnam Machine Company, 1875

23

Configuration Control

• Software that enables changes in switch configuration while the switch is operating– Ensures that requested configurations are valid

and safe– Reconfigures– Example: Remove a Protocol Handler (PH) from

service and replace it with a spare

• New switching technology requires new configuration controllers– New unit types for new functionality of lower cost

24

Maintenance Domain Structure

Human MachineInterface

Diagnostics

Hardware SoftwareInterface

MaintenanceAdministrator

Fault Detectionand Analysis

RoutineMaintenance

InitializationControl

ConfigurationControl

25

Commonality Analysis of Configuration Control

• 1 staff-year effort over 6 months by 6 experts

• Produced a Commonality Analysis– Definitions: rational vocabulary– Commonalities: reusable algorithms– Variabilities: relationships between devices– Parameters of Variation: enumerated types

• Reviewed by organization

26

Building Technology for Configuration Control

• 2 staff-years effort over 12 months by 3 experts

• Languages -- capture generic algorithms and parameters

• Translators -- translate to executable code

• Interface to legacy system• Graphical editor

27

SMALL-D

Configuration Control Architecture

SMALL-V SMALL-R

Domain Engineering Environment

Application Engineering Environment

VFSMC Data

Application

RAD

28

Configuration ControlDevelopment Environment

ApplicationEngineer

DomainEngineer

Application SpecificConfiguration Control

ReusableAssets

ApplicationData

ApplicationEnvironment

Interface

RAD

C Code

KnowledgeBase

29

RAD Tool

30

Reusable Assets

• Validations -- generic algorithms for every unit type

• Realizations -- generic algorithms for every unit type

• Relationships– data that is used to drive the generic algorithms– design information shared across development

31

Applications• Project 1 (1994)

– re-engineering project to demonstrate feasibility– replaced existing code and demonstrated in lab

• Project 2 (1996)– shadow project to demonstrate performance– duplicated work of another team and compared results

• Project 3 (1997-1998)– first real application– reworked domain analysis as work progressed

• Project 4 (1999)– production use

32

CAL HSIDECC

PSAD

AIMTLP

TRPTAC

0

20

40

60

80

100

Interval Reduction on 5ESS Projects

33

Measuring Benefits

• Siy and Mockus studied the effect of domain engineering on the AIM project:– Studied 22,804 MRs involved in 1351

distinct software features over a 7 year period

– Found that domain engineered MRs took 1/4 of the time of other MRs

– Total savings was $6M - $9M for 1999.

34

Where is Domain Engineering Being Used in Lucent?

• Switching– Naperville, IL– Boulder, CO– Hilversum, Netherlands– Malmesbury, England– Poland

• Wireless– Software development processes

35

Why Did Product Line Engineering Work

(at Lucent)?

36

Diffusion of Innovations• Classic work by Everett M. Rogers (ISBN 0-02-926671-

8)• Discovered keys to technology transfer:

– Relative advantage• How much better is it?

– Compatibility• Is it consistent with values, experiences, and needs?

– Complexity• How difficult is it to understand and use?

– Trialability• How easily may it be tried experimentally?

– Observability• How visible are the results of use?

37

Technology Transfer at Lucent

• Estimates are that we only use about 10% of the good ideas developed within Bell Labs Research

• What’s wrong with the other 90%?– Relative advantage?– Compatibility?– Complexity?– Trialability?– Observability?

38

Oral Culture of 5ESS

39

Problems of Oral Culture

• No History (Goody and Watt)– Story changes with each telling– Evolution breeds decay

• No abstraction (Luria)– Insistence on reasoning in terms of ground

elements– Refusal to extend arguments to

abstractions

40

From Orality to Literacy

• Write it down

• Identify abstractions

• Construct languages

• Create in the new languages

41

Power of Written Language

• Generic algorithms of Configuration Control– Translated to flowcharts and English for review– Executed in simulator for further review– Translated to VFSM for execution

• Commonality Analysis of Configuration Control– Starting point for DECC implementation– Starting point for 4 other designs

42

Diffusion of Domain Engineering

• Relative advantage: – Solution to the right problem

• Compatibility: – by the right people

• Complexity: – using the right tools and methods

• Trialability:– so that anyone can try it

• Observability: – and see the results

43

Conclusion

• Domain engineering reduces interval and cost of software development

• Resulting products are more consistent and easier to maintain

• Capturing domain knowledge in written form was the key

44

References

Siy and Mockus, "Measuring domain engineering effects on software coding cost", 6th International Symposium on Software Metrics, 304-311, November 4-6, 1999.

Ardis, Dudak, Dor, Leu, Nakatani, Olsen, Pontrelli, "Domain engineered configuration control", Software Product Line Conference, August 28-31, 2000.

Ardis and Green, "Successful introduction of domain engineering into software development", Bell Labs Technical Journal 3(3), July-September 1998.