Came across this interesting and thought provoking YouTube video of Linus Torvalds talking about Source Code Management and GIT to Google employees. It is a long one, over an hour, and with pretty harsh words (sales technique -- I assume) for CVS/SVN, most other commercial SCM tools, and their users but is worth watching.
My key takeways:
- Use a tool that meets your or your organizations development process. Conversely, the tool you use will define the process. Linus illustrates this well with the "committers club" based process that has developed around most OSS projects that use CVS/SVN as their SCM tool. Also, how these tools fall short to support Linus's main activity of accepting patches (read: merging branches) to his tree. However, can't really see most commerical organizations using a development process that Linus follows for Linux kernel.
- CVS/SVN work on a centralized repository with "slow" over-the-network check-in and checkouts. GIT, and other similar tools, work on a local repository with good support to merge branches from remote repositories. CVS/SVN suck at merging different branches and hence are rarely used. Agree that maintaining branches with either CVS and SVN is a pain. Haven't used GIT or other similar tools, so can't really comment.
- Speed of doing SCM activities matters a lot to Linus. And he is not talking about the response time for specific commands but the overall time consumed in SCM activities. Having witnessed the frustration of multi-hour checkouts from a remote ClearCase repository, I cannot agree more.
- Integrity guarantees provided by SHA-1 hashes (though, for some reason, Linus referred this as "Consistency" in his talk) as a safeguard against break-ins and/or disk corruption seem to matter a lot to Linus.