Software Configuration Management: Under the Hood of Two Leading Tools

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Software Configuration Management Under the
Hood of Two Leading Tools

• Presented by Andrew Wheeler Shane Marcus

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Agenda

• Project Motivation
• CM Tools Investigated
• ClearCase
• Subversion (SVN)
• Comparison
• Future Work

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Project Motivation

• Critical to software projects survival and
  completion
• A means of document control
• CMMIs demands
• Good SCM decisions can lead to a streamlining of
  the process
• Most popular SCM tools covered

4
ClearCase Background

• Initiated from DSEE
• Domain Software Engineering Environment
• Atria Software (Early 90s)
• Initially Released to UNIX Platforms
• Windows Support Came Later
• Rational Tool Alignment
• IBM Buyout

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Subversion (SVN) Background

• Shell Scripts Written by Dick Grune
• Resolve Conflicted Code
• Merge Two Files
• Brian Berliner Transformed Scripts (89)
• CVS was Born
• Subversion Derived from CVS
• Marketed as a Compelling Replacement to CVS
• Built by CollabNet, Inc.

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Comparison Areas
Evaluation
Networking
Atomic Commits
Directory Support
File Support
Remote Repository
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Differences in Comparison
Comparison Area ClearCase Subversion (SVN)
Networking Poor (Chatty RPC protocol) Very Good
Ease of Deployment Poor (Difficult and Complex) Excellent (lt 10 Minutes)
Remote Repository Replication Indirectly (Multisite) Indirectly Add-on or Utility
Evaluation On-line Only No Limitation
Cost 4250 / 5100 Free
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Related Work

• User Driven Evaluation
• Rose-Hulman Institute of Technology
• Used as repository for course materials and
  collaboration source among professors
• Feedback to students on coursework through SVN
• Collaboration among teams and backup structure
  for students

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Related Work (cont)

• Collaboration and SCM
• COVEN
• Presents key issues facing current SCM tools
• Branching and Merging
• Revision history and Reverting
• Labeling and Tagging

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Future Work

• Perform study of software projects who use SCM
  tools
• Collect needs through surveys and rate them
  against the features of a given SCM tool
• Collect metrics on how quickly a project can
  setup a repository structure
• Collect metrics on how much time is spent
  performing a given activity with the same amount
  of SLOC changes per SCM tool
• Compare SCM tool usage to staff size

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Conclusion

• ClearCase vs. Subversion (SVN)
• Feature Sets Nearly the Same
• Proprietary vs. Open Source
• Significant Cost Difference
• Initial Setup Time
• Difficult to Eliminate Biases
• Restricted Evaluation / Training Opportunity
• ClearCase On-line Only Evaluation
• Relied on Work Exposure to Product