Version control systems (VCS) allow developers to manage code through capabilities like reversibility, concurrency, and annotation. Subversion is a popular centralized VCS that was released in 2000. It uses a trunk-branch-tag structure where the trunk contains stable code, branches are for development work, and tags create snapshots. Developers check code out from the repository, check changes in after making modifications, and view file histories.

1. VERSION CONTROL SYSTEMSUBVERSION

2. WHAT IS VCS ?A version control system (VCS) is a tool for managing a collection of program code that provides you with three important capabilities: ReversibilityConcurrencyAnnotation

3. WHAT VCS DO ?There are three basic things you can do with a VCSCHECK OUTa work file copy from a repositoryCHECK INor COMMIT a change in a work file to its master in a repositoryVIEW HISTORY of files. Everything else VCS’s do is an elaboration or support for those three operations.

4. EVOLUTION OF VCSYou’ve all used at least one of the Sub Version Control Management (SCM) on the following list, but are you aware of how long the system you’re using has been around? Do you know the big names? Here is a short compilation of VCS.PRE HISTORYRCS [Released in 1982]THE CLASSIC ERACVS [Released in 1990]Contd. . .PVCS

5. ClearCase

6. VSS

7. PerForceENTER THE MIDDLE AGESSubversion [Released in 2000]Contd. . .AccuRevENTER THE RENAISSANCE BitKeeper [Released in 2002]

8. Mercurial [Released in 2005]

9. Plastic SCM [Released in 2006]

10. GitReleased [Released in 2007]Contd. . .Bazzar [Released in 2008]

11. Darcs [Released in 2010]

12. Team Foundation Server.CATEGORIZING VCSThere are three fundamental ways in which VCS’s can differ from each other:They can be centralized or decentralized.

13. They can be locking, merge-before-commit, or commit-before-merge.

14. They can do file operations or file set operations.CVS Diagram

15. DVCS Diagram

16. VERSION MANAGEMENT USING XCODEXcode provides several ways to save versions of your project:Take a Snapshot of Your Project. Project ArchivingKeep Track of Changes with Source Control. [Using SVN or GIT]An archive packages your products for distribution, either through your own distribution mechanism or for submission to the App Store.

17. SVN Subversion is probably the version control system with the widest adoption. Most open-source projects use Subversion as a repository because other larger projects, such as Source Forge, Apache, Python, Ruby and many others, use it as well.Google Code uses Subversion exclusively to distribute code. In Subversion (often abbreviated SVN), code is stored in a repository, which is located somewhere on the network. (To use Subversion for your personal projects you can create your own repository as well.)

18. SVN WORKING MODEL

19. SVN ARCHITECTURESVN Client ProgramRepository Access Layer-DAV-SVN-LocalSVN Repository

20. Lets get started !!ANALOGYWorking with SVN is somewhat like growing a tree:Atree has a trunk and some branches.Branches grow from the trunk, and thinner branches grow from thicker branches.Atree can grow with a trunk and no branch (but not for long).

21. Contd . .A tree with branches but no trunk looks more like a bundle of twigs fallen on the floor.If the trunk is sick, so are the branches and eventually, the whole tree can die.If a branch is sick, you can cut it, and another one may grow.If a branch grows too much, it may become too heavy for the trunk, and the tree will fall down.When you feel your tree, your trunk, or a branch is nice looking, you can take a picture of it to remember how nice it was that day.

22. SVN TRUNK The trunk is the main place were stable code can be found. This is like the assembly line of a car factory, putting finished car parts together. Dealing with SVN trunk, you should keep following things in mind:NEVER work directly on the trunk.

23. Do not commit changes (from a branch merge) to the trunk which may break it.SVN BRANCHES A branch is a “cheap copy” of a subtree (ie, the trunk or a branch) of a SVN repository. Dealing with SVN branches:If you need to alter your application or develop a new feature for it, create a new branch.New branches must be created from the trunk, except for new sub-branches (if needed) which must be created from a branch.When you create a new branch, you should switch to it immediately.When a branch is completed and considered stable, it must be merged back to its original copy, that is: back to the trunk if it was copied from the trunk, or back to its parent branch if it was copied from a branch.

24. SVN TAGS It is a snapshot with a name of a specific revision of the trunk, or of a branch. Dealing with TAGS:Do never switch to/checkout from/commit to a SVN tag: a tag is some sort of “picture”, not the real thing; tags are to be read, never writtenOn specific/critical environments (production, staging, testing, etc), checkout and update from a fixed tag, but do never commit to a tag.When the trunk is stable and ready to be released publicly, re-create tags accordingly, then update the concerned environments (production, staging, etc)Do not tag a tag

25. SVN COMMANDSThe underneath link is a download link to a text file enlisting the basic commands used in SVN:http://dl.dropbox.com/u/35724246/TA_MONDAY_SESSIONS/Session_6.3_28-9-2011.txt

26. Creditshttp://svnbook.red-bean.com/en/1.5/index.htmlhttp://www.clear.rice.edu/comp314/svn.htmlhttp://www.smashingmagazine.com/2008/09/18/the-top-7-open-source-version-control-systems/http://developer.apple.com/library/mac/#documentation/ToolsLanguages/Conceptual/Xcode4UserGuide/SCM/SCM.htmlhttp://www.infoq.com/articles/dvcs-guidehttp://codex.wordpress.org/Using_Subversion

27. THANK YOU.