1 practical experience with software evolution in statoil asa sevo seminar, 16 march 2006 odd petter...

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Practical Experience with Software Evolutionin Statoil ASASEVO Seminar, 16 March 2006

Odd Petter N. Slyngstad and Anita Gupta, Practical Experience with Software Evolution in Statoil ASA, SEVO Seminar 16.03.2006

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Overview


Two studies at Statoil ASA Context and Contribution

Study#1: Investigation of Software ReuseResearch Questions and HypothesesAnalysis and ResultsDiscussion

Study#2: Survey on Developers’ views on Software ReuseSurvey set-upResearch QuestionsResults from the Survey

Ongoing and Future Work

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Context and Contribution

Context: Statoil ASA is a large Oil & Gas company, has ~24000

employees worldwide, represented in 28 countries Contribution:

Better understanding and management of software evolution

Goal: Possible to use results as baseline for comparison


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Investigation of Software Reuse: Study Objects, Research Questions, Hypotheses and Results


Study Objects: Change Requests (202 CR’s) and Trouble Reports (ca 200 TR’s) for 6 of 7 reusable JEF (Java Enterprise Framework) components (ranging in size from 268 SLOC to 8885 SLOC), over three releases.

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Investigation of Software Reuse: Research Questions, Hypotheses and Results

Research Questions: RQ1: How does defect-density in reusable components evolve

over time?H10: The defect-density in JEF components do not change

with timeH1A: There is a difference in defect-density for JEF

components over time Result: ANOVA analysis resulted in the null hypothesis being

rejected, hence there is a significant difference in defect-density for JEF components over time.

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Investigation of Software Reuse: Research Questions, Hypotheses and Results

RQ2: How does the change-density for reusable components (stability) evolve over time?

H20: The change-density in JEF components does not change with time

H2A: There is a difference in the change-density for JEF components over time

Result: ANOVA analysis proved inconclusive here, so we cannot reject null hypothesis here. However, the data trend is nevertheless declining change-density for most of the components.


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Investigation of Software Reuse: Discussion of results

Quality attributes (defect-density and change-density) can be used to partially characterize evolution, as they show how the quality of the reusable JEF components evolves over time: Defect-density: Analysis indicates decreasing defect-density over time

for most of the components Change-density: Unable to conclude without further analysis Lower defect-density over time indicates an increased level of achieved

quality for the reusable components. Change-density (stability) is important to achieve stable evolution of the components and resources assigned to adapt/perfect the reusable components


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Survey on Developers’ Views on Software Reuse: Survey set-up

Questionnaire design: 30 Questions, 11 pages, 5 sections, 12-14 min. fill-in time.

Survey performed with short qualitative follow-up interviews.

Respondents were all developers involved with the DCF and S&A development projects, as well as those on the JEF team, 16 in total.


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Survey on Developers’ Views on Software Reuse: Results (1)

RQ1: What are the key benefits of reuse? Result: Lower development costs, shorter development time, higher

component quality as well as standardized architecture seen as benefits of reuse.

RQ2: Which factors contribute to facilitate reuse? Result: Improved documentation through information repository could

be beneficial. RQ3: Does reuse increase rework?

Result: Inconclusive, we can show no link between reuse and rework.


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Survey on Developers’ Views on Software Reuse: Results (2)

RQ4: Do developers have sufficient information to understand the relevant components? If the answer is no, how can they solve this problem? Result: Most developers have sufficient information, but

documentation should be improved. RQ5: Do developers trust the relevant quality specification of

the components? If the answer is no, how can they solve this problem? Result: Quality specification not trusted for reusable components –

should be improved.


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Survey on Developers’ Views on Software Reuse: Discussion

The promise of CBSE is the management of software evolution through software reuse, hence it is important to investigate the software reuse practices.

The results show that while significant benefits are seen from software reuse, improvements in documentation and quality specifications of the reusable components need to be made. Also, reuse does not appear to have a link to rework.

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Ongoing and Future Work

In-depth analysis of change-request data related to the JEF components, on trends related to software evolution.


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Questions and Comments?

[email protected] [email protected]

www.idi.ntnu.no/grupper/su/sevo/


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http://www.idi.ntnu.no/grupper/su/sevo/

1 practical experience with software evolution in statoil asa sevo seminar, 16 march 2006 odd petter...

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