balancing agility and discipline chapter 4 sharon beall eecs 811 april 22, 2004

Balancing Agility and DisciplineChapter 4

Sharon Beall

EECS 811

April 22, 2004

2

Agenda

Lease Management Example Command Center Processing and

Display System Replacement (CCPDS-R) Example

Home Ground Charts Summary

3

Lease ManagementThe Project

Leasing industry 500 KLOC 30 developers 20 participants 1,000 story cards 18 months with traditional approach 36 months with XP

4

Lease Management Eight “Bad Smells”

1. Time to develop story card increased in later iterations

Iteration length static Too much tacit knowledge required Stories subdivided to meet schedules

5

Lease ManagementEight “Bad Smells”

2. Integrating functions problematic in later iterations

Individual tests okay Failed integration with other functions High-level architectural plan developed

6


3. Unit and system testing issues Tacit knowledge strain again Complex specialized functions Breaking tests, architecture High-level architectural plan assisted

7


4. Customer complaints No complaints until later iterations Customer never understood real user

needs Early coaching necessary

8


5. Integration, Schedules, and Effort Misrepresented accomplishments Story cards taking extra effort than

portrayed Created task list for each story Monitored by management

9


6. Refactoring Never Done Developers knew refactoring was needed Busy doing assigned work Detailed work plans and task lists included

refactoring

10


7. Simple design and YAGNI drawbacks Developers continuously refactoring some

modules High costs since future changes known for

those modules Adopted a pattern for this module after

some time(YAGNI – You Aren’t Going to Need It)

11


8. Test drivers and re-use Normally simple design and YAGNI Due to size and number of objects,

different tests with similar drivers for different object states

Adopted a pattern for test drivers as well

12

Lease ManagementLessons Learned

Tacit knowledge is agile, however with large software projects, presents scaling problems

To diverge from an agile process requires talented people to recognize and respond

Simple design is risky on large projects with known change

14

Lease ManagementExtending XP

High level architectural plans Definitions of milestones and

completion criteria Usage of patterns and architectural

solutionsAuthors note…scale agile processes

as-needed and as-discovered!

15

CCPDS-RThe Project

Re-engineer command center for missile warning system

1 million lines of code 75 programmers 3 user sets 48 months

16

CCPDS-RAgile Manifesto

Individuals and Interactions over Processes and Tools

TRW versus DoD

DoD milestone standards redefined to reflect stakeholder’s interest. Use of automated tools to verify software to specs.

Contract award fees designated for personnel System architecture organized for developers’

skill levels

17


Working Software over Comprehensive Documentation

DoD requires Preliminary Design Review (PDR) with docs and charts

TRW chose to put it off until software could be demonstrated

Documentation generated for those who really really needed it

18


Customer Collaboration over Contract Negotiation

Win-win idea used to negotiate contracts Ada version of COCOMO used Allowed for savings via reuse (if Agile,

would have been costs due to YAGNI and rework)

19


Responding to Change over Following a Plan

Plans and specs were machine processable Metrics tracked progress in identifying

problems Allowed easy tracking and early fixes Easy adaptation of plans Advance work in software reuse amongst 3

customer sets

21

CCPDS-R Extending Plan-Driven Methods

A win-win customer driven view can be combined with a process-document driven view

Award fees generated for TRW developers

22

Summary

Examples that hybrids can succeed Easily tailoring the process not published Taking parts of each method to

complement a given project is not easy, but can be successful

…Guidelines in the next chapter to do this!

23

Closing

Questions? Comments?

balancing agility and discipline chapter 4 sharon beall eecs 811 april 22, 2004

Documents