What source code repository should I use for source code control or source code management (SCM)?

Reasons to consider using source code control

• Developer has multiple machines for development, can get difficult to remember which machine has the latest version of a project.
• Having all source codes for all projects in one place
  • Can enhance code reuse

Choices for source code management

Documentation about SCM software

• Subversion
  • google:subversion source code management
  • Why use subversion: http://copenhagen.pm.org/presentations/subversion/subversion.htm
  • http://www.orcaware.com/svn/Subversion-Blair_Zajac.ppt - 31 slides
    • Why us cvs vs. svn - (What is cvs)
      • Functional replacement for CVS
      • Directory versioning (renames and moves)
      • Atomic commits (all or nothing)
      • Faster network access (binary diffs)
      • File & directory meta-data
      • Requires less network access
    • Subversion client side
      • Each working directory has a .svn directory
      • Similar to CVS's CVS directory
      • Repository password stored in each .svn
      • Stores a pristine copy of each file in directory - Nice
    • Two locations of SVN repositories
      • On a local filesystem
      • Typically used for a single developer
      • Accessed via direct file read/write access
      • Requires that users have local accounts
      • Uses filesystem and user/group security
    • On a remote system
      • Accessed via a HTTP or HTTPS connection
      • Does not require that users have accounts on the server
      • Use Apache style authentication
    • Subversion server design
      • Server uses Apache web server
        • Browse repository with Internet Explorer or Netscape
        • With mod_deflate, compression can be used between client and server
      • Repository uses Berkeley Database
        • Data integrity
        • Atomic writes
        • Recoverability
        • Hot backups
    • Command line differences
      • CVS
        • Argument position matters
        • % cvs -d /export/home1/cvs update -d
      • SVN
        • Argument position does not matter
        • % svn log -r 123 foo.c
        • % svn log foo.c -r 123
    • How do revisions work
      • Revision numbers are applied to an object to identify a unique version of that object
        • Example files
        • % ls
        • bar.c foo.c
      • CVS
        • Revision numbers are per file
        • A revision number from one file does not necessarily have any meaning to another file with the same revision number
        • A commit only updates the revision numbers of files that were modified
        • bar.c may be at revision 1.2 and foo.c at 1.10
        • Updates to bar.c will not change foo.c's revision number
      • Subversion
        • Revision numbers are global across the whole repository
        • Identify how the entire repository looks at that instant in time
        • A commit creates a snapshot of the entire tree in the repository at that revision number
        • Allows users to say, "Hey so-and-so, go get revision 1432 of XYZ and try to compile it."
        • Before an update, both bar.c and foo.c are at revision 25
        • Modify bar.c and commit
        • Then update the working copy
        • Now bar.c and foo.c are at revision 26, except that foo.c in revision 25 and 26 are identical
        • No additional space in repository required, i.e. a cheap copy or a symbolic link is made