Slides of my talk "Why you should be using a distributed version control system (DVCS) for your project", first presented at SAPO CodeBits in Lisbon, Portugal on 2009-12-03.

1. Why you should be using a
distributed version control system
(DVCS) for your project
Lenz Grimmer <lenz@grimmer.com>
<
http://lenzg.net/ | Twitter: @lenzgr
2009-12-03
SAPO Codebits | Lisbon | Portugal

2. Agenda
● Disadvantages of the central
approach
● DVCS Concepts and Advantages
● Overview: Bazaar, git, Mercurial

3. $ whoami
1998 2002
2008 2010?

4. Disadvantages of the centralized
approach
(e.g. Subversion and CVS)

5. Most operations require
communication with the central
repository

6. Checkpointing your work
requires committing to the
central repository

7. Branching and merging
considered painful

8. Collaboration is hampered

9. DVCS: Concepts and
Advantages

10. There is no central instance
(Well, duh!)

11. Disconnected operations

12. Local commits

13. Easy branching and merging

14. Multi-protocol support

15. Sample workflows

16. Solo Workflow
● Create project
● Commit changes
Hack ● Review/browse
history
● Tag/publish release
● Apply new changes
● Rinse & Repeat

17. Pair programming
Create repository
HackCommit
Hack
Commit
Branch
Push, pull, merge
Pull and merge
Developer A Developer B

18. Code deployment
Commit
Upstream Live site
project
Hack
Merge
Branch
Push
Developer

19. Central Branch & Gatekeeper
Developer A Developer B
Branch, Merge,
Edit, Commit,
Pull
Push Edit, Commit,
Push
Merge, Review
Push
Central repository Gatekeeper

20. Overview: Bazaar, git, Mercurial

21. Comparison aspects
● Usability differences
● Project hosting sites
● OS support
rd
●
3 party tools (e.g. IDE integration, GUIs)
● Plugins/Extensibility
● Speed
● Reference projects
● Handling of branches and merges

22. Bazaar
● Python
● Sponsored by Canonical
● Hosting Platforms: Launchpad | Sourceforge
● Many plugins
● One branch per directory – simplifies the UI
● IDE/GUI support
● Strong OS support (incl. Windows)
● References: Debian apt, awn, Gnash,
MySQL, Ubuntu

23. git
● C | Perl | Shell
● Originated from the Linux Kernel Community
● Speed first, usability later
● Powerful, but steeper learning curve
● Multiple branches per directory
● Platforms: Kenai, github, gitorious,
SourceForge
● References: Linux Kernel, Ruby on Rails,
jQuery

24. Mercurial
● Python
● Plugins
● Platforms: Bitbucket, Google Code, Kenai
● Multiple branches per directory (named
branches)
● A „pull“ updates the repo, not the working
copy
● References: NetBeans, OpenJDK,
OpenOffice, OpenSolaris, Python

25. Q&A
Questions, Comments?

26. Thank you!
Lenz Grimmer <lenz@grimmer.com>