software development processes

1The INI is a cooperative endeavor of: College of Engineering School of Computer Science

Tepper School of Business Heinz College

Software Development Processes

Kun Niu

Spring, 2011

April 7th

05-899D Human Aspects of Software Development (HASD)

The Information Networking Institute is a cooperative endeavor of:

College of EngineeringSchool of Computer Science

Tepper School of BusinessHeinz College



Agenda Definition Software Development Lifecycle Software Programming Process Software Development Activity Summary



Agenda Definition



Definition• Software Development Lifecycle

- Also known as a software development process, is a structure imposed on the development of a software product. (Agile, Waterfall, etc.)[Wikipedia]

• Software Programming Process- The process of designing, writing, testing, debugging / troubleshooting, and maintaining the source code of computer programs (Test Driven Development, Model Driven Development, etc.)

• Software Development Activity- Detailed technique used in software programming process (Pair programming, Rubber duck debugging, etc.)



Why do people do research in these fields?

• Improve the probability of project success – Software development lifecycle

• Improve the productivity of the whole programming processes – Software programming process

• Improve the productivity of a specific phase of software programming process – Software programming activity



Agenda Definition Software Development Lifecycle



Usage and Perceptions of Agile Software Development in an Industrial Context: An Exploratory Study [Begel, 2007]

• Contribution• Try to understand how Agile Software Development methodologies

are used in large scale industry• Dominant agile practices and methodologies• Common benefits and problems associated with ASD



Exploratory Study Design• A web-based survey

Email to 2,821 recipients out of 28,000

• Demographic (response) 18% for developers 18% for testers 10% for managers Average 9.2 years of software development experience (0 - 35 y)

• Survey Design Survey sections: Demographic, Agile development, Pair

programming Card sort: free response for benefits and issues



Collocation Data Use Agile?Collocated dynamics Yes No

Not-collocated 12 29Same country 4 10 Same city 1 2 Same campus 8 12 Same building 24 35 Same floor 68 138 Same hallway 25 76 Same office 14 18 Total 156 321

Many respondents using Agile of survey collocate in the same place



Methodologies used



Practices used



Team attitudes and morale factors

60% people agree Agile work well for them and their team.Less than 40% people think Agile can work for large groups.



Benefits and problemsBenefits

Problems

Why not use?



Threats to validity• Participants bias• Unknown team size and group size• Difficult to generalize because of different Microsoft’s

product context



Rapid Software Developmentthrough Team Collocation [Stephanie, 2002]

• A field study conducted at a fortune 500 auto mobile company

• Collocated software development team using Rapid Software Development Center

• Six projects from different areas of the company• Prototyping, iterative development using “timeboxing”• Report by a combination of case study and empirical

evaluation



Room Layout



Measures• Productivity Metrics

Function points normalized by certified Functional Points Foundation Group Member

• Cycle Time Number of months per 1000 functions

• User Satisfaction Composite of factors like ease of use, system performance etc.

• Measures of Team Experiences How often they will use rooms and hoteling space, conference room



Measure results(pilot teams)

Productivity Measures

Satisfaction Measures



Measure results (with subsequent team)Productivity Measures

Satisfaction Measures

Entry versus Exit questionnaire data



Conclution• Benefits

Improve productivity (timeboxing and facilities)

• Issues Large projects No accurate quality information Don’t know if the increased productivity was due to Hawthorne



Agenda Definition Software Development Lifecycle Software Programming Process



Test Driven Development



Evaluating the Efficacy of Test-Driven Development: Industrial Case Studies

• Bhat, 2006 from Microsoft• Two case studies, Windows and Messenger (A and B)

Project organizationsProcess timelines and defect

density measurement



Case Study AContext Factors

Outcome measures

Product measures



Case Study BContext Factors

Outcome measures

Product measures



Result



Threats to validity• High quality code resulted from a new process

Alleviated by the fact that all were professional programmers who had their own tasks

• The projects may be easier and the comparison may be in accurate Alleviated by the projects in the same organization and the

complexity may be to the same degree

• Hard to generalize in different environment and different contexts The authors are trying to collect data from other TDD projects



A Survey of Evidence for Test DrivenDevelopment in Academia• Chetan, 2008• Surveys the current state of TDD experiments

conducted at universities



Misconceptions about TDD• You create a 100% regression test suite.

Not always cost-effective(UI)

• Unit tests form 100% of your design specification. Design document is necessary

• You only need to unit test. System integration test, performance test

• TDD does not scale. Divide into small suites



Research conducted by someone else



TDD introduction & learning• Introduction

Courses include> Explaining automated unit test> Describing TDD> Providing document> Supplying examples

Edward introduced at the beginning of the class, and used throughout the entire experiment

> Reinforce may be a key

• Learning Incremental instructional approach Test driven learning – Learn by example



Conclusion• TDD exposes students to analytical and

comprehension skills needed in software testing• TDD tends to help students with the design of complex

projects, and increases student confidence.• Test-driven development reveals valuable software

testing skills to fledgling programmers; the next step is figuring out how and when to introduce it into a curriculum.



Agenda Definition Software Development Lifecycle Software Programming Process Software Development Activity



The Social Dynamics of Pair Programming• Jan 2007• The paper presents a series of pair programming

interactions drawn from a long term ethnographic study of two software development teams

• Term used in pair programming such as “driver” and “navigator” may not be right



Pair programming history• Beck’s book <<Extreme Programming Explained>>There are two roles in each pair. One partner, the one with the

keyboard and the mouse, is thinking about the best way to implement this method right here. The other partner is thinking more strategically:

- Is this whole approach going to work?- What are some other test cases that might not work yet?- Is there some way to simplify the whole system so the current

problem just disappears?

• Few studies focuses on the nature of interactions



Research• Four months ethnographic study• Two software development teams• Have a long history of pair programming



Findings• Both software development teams differed greatly

from the driver and navigator roles described in the academic and practitioner literature

• When the two programmers had equivalent expertise, they engaged jointly in programmer activities.

• When the distribution of task-relevant expertise differed, the programmer with more expertise dominated the interaction.

• Keyboard control had a subtle, but consistent effect on decision making.



Implication of the research• The pairs appeared to be most effective when both programmers

took on driver and navigator responsibilities• Programmers felt more engaged in their tasks when they either

had keyboard control or keyboard control was imminent• Expertise emerges as a particularly important factor influencing

pair interactions Pairing less knowledgeable programmers with more knowledge

programmers did seem to be effective when the less knowledgeable programmer was new to the team and code base

• Programming partner rotation appeared to be effective in ensuring increased dispersion of code knowledge across the team, rotating late in the task may break up an effectively functioning pair and introduce a new programmer in a disadvantaged position



Pair Programming: What’s in it for Me? • Begel, 2008• Report on a longitudinal evaluation of pair

programming at Microsoft Corporation• Understand how pair programming methodologies are

used, what kinds of problems and benefits they are perceived to have, the types of partners people would like to work, and a general consensus on PP‟s usefulness in the software engineering professional community

• A web-based survey of Microsoft developers



Contribution1. Quantitative data on the adoption of pair programming in a large software company. 2. The perceived benefits and problems of pair programming. 3. The characteristics an engineer looks for in an ideal pair programming partner and team. 4. The perception that pair programming produces higher quality code at the expense



Previous study result• Different universities have opposite results in PP

research• Different industrial projects also have different result• Conclusion from the author

Pair programming appears to be very different in academic than in industry

In academia, pair programming is used for education and has positive effects on student retention.

In industry, there is little research on pair programming, and what little there is shows conflicting results.

No good qualitative assessment of how professional programmers might explain these results.



Effect of Pair Programming on Work



PP benefits & problemsBenefits Problems



Attributes of good programming partners and teams

Attributes of Good Partners Attributes of Good Teams



Agenda Definition Software Development Lifecycle Software Programming Process Software Development Activity Summary



Session Summary• Software development lifecycle

• Tools tend to provide quantitative data to help manager’s judgment• How to generalize the result is still a problem (Can be solved?)• How to improve the accuracy of result?

• Software programming process TDD is a widely researched field both in industry and in academic How to make people accommodate it is still a problem

• Software development activity Pair programming in XP is popular Industry studies show difference real use and academic research



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software development processes

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