Software Engineering II

Lecture 1

Fakhar Lodhi

Software Engineering - IEEE

1. The application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software; that is, the application of engineering to software.

2. The study of approaches as in 1.

‘all aspects of software production’ - Software engineering is not just concerned with the technical processes of software development but also with activities such as software project management and with the development of tools, methods and theories to support software production.

-Sommerville

Software Engineering

A software engineer is challenged to produce high-quality software with finite

amount of resources and to a predicted schedule and budget.

Law of diminishing returns

Making the engineering decision!

Benefit

Cos

t

Software Engineering

Software Engineering is not just about producing software, but about producing software in a COST-

EFFECTIVE manner.

The Balancing Act!

Potentially conflicting requirements

Cost vs. Efficiency Cost vs. Reliability Efficiency vs. User-interface

Challenge is to balance these requirements.

Software Development Loop

ProblemDefinition

SolutionIntegration

TechnicalDevelopment

Status Quo

The name of the game is continuous change and evolution in all

dimensions!

Well-Engineered Software

Provides the required functionality

Reliable User-friendly Cost-effective

Efficient Maintainable

Breakdown of Effort Cost - Software Cost Estimation by

Capers Jones No. Activity Effort1 Requirements 3.84%2 Prototyping 4.50%3 Architecture 2.25%4 Project Plans 1.33%5 Initial Design 3.84%6 Detailed Design4.50%7 Design Reviews3.02%8 Coding 13.50%9 Reuse acquisition 1.13%10 Package Purchase 1.69%11 Code Inspection 4.50%12 Independent V&V 5.42%

13 Configuration Mgt. 0.41%14 Integration 2.71%15 User Documentation 9.67%16 Unit Testing 4.50%17 Function Testing 4.50%18 Integration Testing 3.84%19 System Testing 3.38%20 Beta Testing 3.02%21 Acceptance Testing 1.94%22 Independent Testing 3.38%23 Quality Assurance 4.50%24 Installation and Training

1.94%25 Project Management 6.75%

Effort Breakdown

• Project Management 8.08%• Requirements 14.43%• Design 11.36% • Coding 13.50%• SQA 30.64%• SCM 13.02%• Integration 6.54%• Misc. ~3%

Software Engineering Practices

• Software product realization• Software project management• Software process management• Software quality assurance• Software configuration management

Management

Construction

project planning and managementconfiguration managementquality assuranceinstallation and trainingetc.

RequirementsDesignCodingTestingMaintenanceetc.

Quality Focus

Process

TOOLS

Task Set

Method

A Software Engineering Framework

Common Process Framework

Umbrella Activities

Framework Activities

TASKS

MILESONES, DELIVERABLES

SQA POINTS

Task Sets

The Process

• A software process is a road map that helps you create a timely, high quality result.

• It is the way we produce software• Provides stability and control• Work Product

– Programs, documents, and data produced as a consequence of the software engineering activities

Process Maturity

• SEI – Software Engineering Institute • 5 maturity levels • Capability Maturity Model (CMM)

INITIAL – Ad hoc Process

REPEATABLE – Project Management

DEFINED – Process Definition

MANAGED – Process Measurement

OPTIMIZED – Process Improvement

CMM Maturity Levels

• Goals• Abilities

Key Process Areas (KPAs)

• Methods for monitoring implementation

• Commitments• Activities

• Methods for verifying implementation

• Software Configuration Management• Software Quality Assurance• Software subcontract Management

Level 2 KPAs

• Software project tracking and oversight• Software project planning• Requirement management

Level 2 KPAs - Continued

• Peer reviews• Inter-group coordination• Software product Engineering• Integrated software management

Level 3 KPAs

Level 3 KPAs - Continued• Training program• Organization process management• Organization process focus

• Software quality management

• Quantitative process management

Level 4 KPAs

• Process change management• Technology change management• Defect prevention

Level 5 KPAs

Software Lifecycle Models

• The way you organize your activities• Lifecycle model is a series of steps through which

the product progresses

1. Vision – focus on why2. Definition – focus on what2. Development – focus on how3. Maintenance – focus on change

Software Engineering Phases

Vision Definition Development Maintenance