Yes, we need hundreds of methodologies!!!

1

It is only in this way we get to know what we do and how we can do

“this what” better!!!! Mira Kajko-Mattsson

Department of Computer and Systems SciencesStockholm University and Royal Institute of Technology

Sweden

Development, evolution and maintenance in ancient times

Programmer

Manager

No process model (write code, fix code) No documentation The programmer was the craftsman? The work product of ”these craftsmen” was not

always of good quality

With time, however……

Programmer

ManagerManager Manager

With time, however……

ManagerManager Manager

Large amount of functionality is never delivered

The product is late, overbudgeted, defective, never delivered, useless, of low quality, etc.

Lack of product and process knowledge

The product is difficult to change

Only as subset of delivered functionality is frequently used

Engineers are overworked

The product quality is too low

Software cost exceed hw cost

We should act like engineers, like software

engineers

Attempts to improve development

RequirementsAnalysis

SystemDesign

ProgramDesign

Coding

Unit &Integration

Testing

SystemTesting

AcceptanceTesting

Operation &Maintenance

Validate

Verify

Verify

V-model

Release 1 Release 2 Release 3Release 1 Release 2 Release 3

RequirementsSpecification

……..…….

Incremental development

Spiral model

• OOAD• CBD• Agile development• Daily Build• Formal methods • MDA

• OOAD• CBD• Agile development• Daily Build• Formal methods • MDA

Requirementsdefinition

System andsoftware design

Implementationand unit testing

Integration andsystem testing

Operation andmaintenance

Software Engineering contra

Good Enough Software Development

We are now challenging the Software Engineering term .

I wouldn’t like to fly a plane having good enough software

We need process models because they

lay out what needs to be done. Improve communication within the organization enable repetition of success ensure that lessons learned are paid heed to improve

schedule and budget predictability cycle time productivity quality (as measured by defects) customer satisfaction employee morale

increase return on investment decrease cost of quality ......