Software Development: Tools and Processes Lecture -2: Basic - - PowerPoint PPT Presentation

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Software Development: Tools and Processes

Lecture -2: Basic concepts

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Software Engineering Process Office

SEPO-CG p 3

The Software Engineering Crisis

• Nearly 1/3 of information technology (computer and software) projects

were cancelled before completion

• Average overrun of project budgets was 189%
• The average schedule overrun for projects that were in difficulty was

222%

• On average, the delivered product contained only 61% of the
• riginally -specified features.
• Only 16% (1of 6) software projects were completed on time, on budget

“Charting the Seas of Technology: The CHAOS Study” The Standish Group, January 1995

• CrossTalk, October 1997

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Software Engineering Process Office

8/17/99 p 13

Percent Rework on Projects

At TRW 30%

(Boehm, 1987)

At NASA Software Engr. Lab 40%

(McGarry, 1987)

At Hewlett-Packard 33%

(Duncker, 1992)

At Raytheon 41%

(Dion, 1993)

From SEI study:

• Rework is 40% - 50% of project costs
• High-maturity organizations can get rework to <10%

(Paulk, 1999)

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Software project statistics

• A (US) Government Study Of nine federal

software projects with a total cost of $6.8M

• - $3.2M worth were delivered but not used
• $2M worth were paid for but not delivered
• $1.3M worth were abandoned or reworked
• $0.2M worth were used after substantial

modification

• $0.1M was used as delivered (one project)

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To avoid such disasters we should gain expertise in SE

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Basic Concepts: Acquiring Expertise

• How can one acquire expertise?

– Concept of information chunking – by George A. Miller – All information should be presented in small digestible units – the limit is 7 + 2 – One can become expert after acquiring 50,000 chunks of information – This usually takes 10 years – Which information chunks should be acquired? – To become software engineering expert - SWEBOK

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What do we understand by Body

• f Knowledge?

Stable core of BOK? Stable core of BOK?

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SWEBOK: Categories of Knowledge

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SWEBOK: Sources of Knowledge

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Basic Concepts: Software Engineering BOK There are 10 areas of Swebok

– Software requirement engineering – Software design – Software construction – Software Testing – Software Evolution and Maintenance – Software Configuration Management – Software Quality Engineering – Software Engineering Management – Software Engineering Infrastructure – Software engineering process

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Software requirement engineering

• Method of requirement gathering
• Requirement gathering = elicitation
• Documentation of requirements
• Analysis of the gathered requirements
• Managing the change in requirements

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Software design

• System hi level design

– architectural design

• System detailed design

– Sub division into modules – Definition of interfaces for modules – Algorithms within modules

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Software construction

• Implementation of software – coding
• Unit testing by the developers
• Performance optimization
• Over-lapping areas with design and testing

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Software Testing

• Black box and white box testing
• Execution of software for finding defects
• It includes all artifacts related to testing

– Test plans – Test cases – Unit tests – Integration tests – Stress tests

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Software Evolution and Maintenance

• Carrying out changes in the software after

deployment

• This is necessary to keep the software

running under dynamic business environment

• Related documentation and artifacts

should be reviewed and updated

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Software Configuration Management

• Identification of the items to be managed

through configuration management

• Deals with the version control
• Deals with the change control

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Software Quality Engineering

• Coordinate activities for developing the

software which satisfies the required quality criteria

• It includes activities like

– Quality planning – Quality measurement – Testing – Reviews

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Software Engineering Infrastructure

• This includes the support of tools

– CASE tools – PM tools – SCM tools – QA tools

• Methodologies

– Formal methods – Code reuse libraries – Practices for disseminating tools and methods

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Software engineering process

• Activities related to improvement of

software development quality

• Improvement of productivity
• Improvement of project management

techniques

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Software engineering code of ethics

• Code of ethics is defined by IEEE & ACM
• This includes

– Public interest – Client and employer – Product standards – Professional judgment – Reputation of profession – Fairness to colleagues – Life long learning of profession

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Benefits of Code of Ethics

• Helps avoid death march projects
• Helps avoid Low-ball bidding
• Helps avoid code and fix development
• Helps avoid knowledge stagnation

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Three Ps of Software Engineering

• Processes

– create discipline in development – build on past experience

• People

– Get the best out of people. How?

• Product

– Specs and testing – feature creep

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What is the most difficult task in software engineering ?

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What is the most important capability of a project manager ?

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Small Oral Quiz

• What is the difference between Skill and

knowledge

• What do we understand by knowledge

management?

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Professional Growth Model

Knowledge Mastery Competency Skills