Software Configuration Management: Under the Hood of Two Leading Tools Presented by: Andrew Wheeler & Shane Marcus

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

Project Motivation Critical to software projects survival and completion A means of document control CMMI’s demands Good SCM decisions can lead to a streamlining of the process Most popular SCM tools covered Critical to software projects survival and completion A means of document control CMMI’s demands Good SCM decisions can lead to a streamlining of the process Most popular SCM tools covered

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 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

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. 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.

Comparison Areas Ease of Deployment Cost Atomic Commits Networking File Support Remote Repository Evaluation Directory Support

Differences in Comparison Comparison AreaClearCaseSubversion (SVN) NetworkingPoor (Chatty RPC protocol) Very Good Ease of Deployment Poor (Difficult and Complex) Excellent (< 10 Minutes) Remote Repository Replication Indirectly (Multisite) Indirectly [Add-on or Utility] EvaluationOn-line OnlyNo Limitation Cost$4250 / $5100Free

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 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

Related Work (cont) Collaboration and SCM COVEN Presents key issues facing current SCM tools Branching and Merging Revision history and Reverting Labeling and Tagging Collaboration and SCM COVEN Presents key issues facing current SCM tools Branching and Merging Revision history and Reverting Labeling and Tagging

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 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

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 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