1、An Introduction to SCM & GForge,Lin Guo guolincs.cornell.edu,2,Roadmap,What is SCM Why do we need SCM Interesting SCM features SCM tools GForge Conclusion,3,What is SCM,Source Control Management Maintain a repository of source files Track all changes Control changes Software Configuration Management
2、 More than source control Manage source repositories,4,Why we need SCM,Source Control Sharing: supports concurrent development Versioning: provide version number and dates Change tracking: find details of a change Archival: reproduce any file from any point Documentation, drawing, etc. Configuration
3、 Management Branch: release version vs. develop version Snapshot of the whole system Prohibit further check-in before release,5,Roadmap,What is SCM Why do we need SCM Interesting SCM features Source control vocabulary Code Sharing Branch Label SCM tools GForge Conclusion,6,Source Control Vocabulary,
4、Update: obtain the latest versions of the code Check-out: obtain the writable version of files Check-in: commit the changes to files Lock/unlock: one only person may modify a file Integrate: combines the changes with others Add/delete: add/remove files to repositories Top-of-trunk: most updated,7,Ro
5、admap,What is SCM Why do we need SCM Interesting SCM features Source control vocabulary Code Sharing Lock Sharing SCM tools GForge Conclusion,8,Code Sharing,Multiple people can work on the same source base without colliding - (1) Lock: locks individual files so only one person at a time can modify i
6、t or (2) Merge: Allows multiple people to modify a source file and the system will automatically merge the changes (usually),9,Locking,Only one person can modify certain source files. Works fairly well if developers work on different areas of the project and dont conflict often Problem 1: People for
7、get to unlock files when they are done Problem 2: People work around locking by editing a private copy and checking in when the file is finally unlocked - easy to lose changes.,10,Merging,Several people can work on a file at once Before committing changes, each user merges their copy with the latest
8、 copy in the database This is normally done automatically by the system and usually works, but you should not blindly accept the result of the merge,11,Roadmap,What is SCM Why do we need SCM Interesting SCM features Source control vocabulary Code Sharing Branching SCM tools GForge Conclusion,12,Bran
9、ching,Brach sources for different purposes When a new version ships, typically create a branch for maintenance Companies ship several products from the same source base Branching repository “fork” and branch off the base repository. Double update: (manually) merge back changes in the branching repos
10、itory,1.0,1.0.1,2.0,13,Roadmap,What is SCM Why do we need SCM Interesting SCM features Source control vocabulary Code Sharing Branching Labeling SCM tools GForge Conclusion,14,Labeling,Label all the files in the source base that make up a product at each milestone Just before and just after a major
11、change (eg. changing several interfaces) When a new version ships, want to fix fatal bugs in the original version.,15,Roadmap,What is SCM Why do we need SCM Interesting SCM features SCM tools GForge Conclusion,16,CSM Tools,RCS “revision control system” In most Unix system, only source control CVS “c
12、oncurrent versions system” Free in linux, also support configuration management SourceSafe well-integrated into other Microsoft developer products, but not on other platforms ClearCase commercial CSM tool SourceGorge (Gforge) Projects are available for public discovery and development http:/gforge.c
13、is.cornell.edu/ (http:/gforge.org),17,Helpful Rules,Archived Files Should Always Compile Update to get your codes “top-of-chunk” Code review Compile and run latest archived files *as a set* before Check-in No Cheating (even “simple bug fixes”) Release a lock after you are done. Dont overwrite someon
14、e elses code,18,Roadmap,What is SCM Why do we need SCM Interesting SCM features SCM tools GForge Conclusion,GForge,20,GForge,GForge is an online SCM system SCM tools: create and control access to CVS and Subversion Collaborating tool: forums and mailing lists; Access control: over the automatically
15、created repository depending on the role settings of the project File release, document management, news announcements, surveys, task managements, etc. Gforge in Cornell CIS https:/gforge.cis.cornell.edu/,21,GForge,22,GForge,23,GForge,24,GForge,25,GForge,26,GForge,27,Conclusion,SCM tools are Very He
16、lpful GForge is a Good Project Tools Available at CIS,28,RCS,File management only Transaction model check out and lock edit check in and unlock Little support for binaries,29,CVS,Built on top of RCS Therefore little support for binaries Database can be remote No locking: merge before commit Fast Int
17、egrates with emacs,30,SourceSafe,Microsofts entry into the field Project-based Checkout-edit-checkin model Built-in web site creation tools Integrates with MSDEV,31,Clearcase,Clearcase is configuration management on steroids You create a view of the database with a config spec, which describes how t
18、o select files from the database. When you set a view, Clearcase creates a virtual filesystem containing only those versions of the files selected by the config spec,32,SourceForge,On-line Version Control System Projects are available for public discovery and development A very good environment for open source projects,
