Version Control

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Version Control

• By Peter, Derek, Carlos

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What is Version Control?

• AKA Revision Control
• Version control involves the management of
  multiple revisions of the same entity.
• In other words, it allow multiple developers and
  teams work on multiple instances of a project by
  tracking all the changes and revisions made to
  that specific resource.

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How is Version Control used?

• It is most commonly used in software development
  to aid in the management of the evolution of
  various entities such as application source code,
  GUI design, various diagrams and charts other
  critical information that may be worked on by a
  team of people.

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Whats out there?

• 2 Examples of Open Source Products
• CVS
• Subversion

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CVS Overview

• CVS is a version control system, and by using it,
  you can record the history of sources files, and
  documents.
• CVS is a production quality system in wide use
  around the world, including many free software
  projects.

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CVS Features

• CVS stores individual file history
• It can run scripts which you can supply to log
  CVS operations or enforce site-specific polices.
• Client/server CVS enables developers scattered by
  geography or slow modems to function as a single
  team.
• The version history is stored on a single central
  server and the client machines have a copy of all
  the files that the developers are working on.
• The network between the client and the server
  must be up to perform CVS operations (such as
  check-ins or updates) but need not be up to edit
  or manipulate the current versions of the files.

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CVS Features continued

• Clients can perform all the same operations which
  are available locally.
• In cases where several developers or teams want
  to each maintain their own version of the files,
  because of geography and/or policy, CVS vendor
  branches can import a version from another team,
  and then CVS can merge the changes from the
  vendor branch with the latest files if that is
  what is desired.
• Unreserved checkouts, allowing more than one
  developer to work on the same files at the same
  time.

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CVS Features continued

• CVS provides a flexible modules database that
  provides a symbolic mapping of names to
  components of a larger software distribution. It
  applies names to collections of directories and
  files. A single command can manipulate the entire
  collection.
• CVS servers run on most UNIX variants, and
  clients for Windows NT/95, OS/2 and VMS are also
  available.
• CVS will also operate in what is sometimes called
  server mode against local repositories on Windows
  95/NT.

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Subversion

• Subversion was created as a replacement for CVS.
  Its advantages include
• Directory versioning
• Directory Tress are versioned through Subversion
  virtual file-system.
• True version history
• You can add, delete, copy, and rename both files
  and directories.
• Newly added files begin with a fresh, clean
  history
• Atomic commits
• Collection of modifications either goes into the
  repository completely, or not at all.
• Allows developers to construct and commit changes
  as logical chunks
• Versioned metadata
• Each file and directory has a set of
  propertieskeys and their valuesassociated with
  it.
• You can create and store any arbitrary key/value
  pairs you wish.

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Subversion continued

• Choice of network layers
• Subversion can plug into the Apache HTTP Server
  as an extension module.
• Consistent data handling
• Both text (human-readable) and binary
  (human-unreadable) files are stored equally
  compressed in the repository, and differences are
  transmitted in both directions across the
  network.
• Efficient branching and tagging
• Subversion creates branches and tags by simply
  copying the project, using a mechanism similar to
  a hard-link.
• Hackability
• Subversion has no historical baggage it is
  implemented as a collection of shared C libraries
  with well-defined APIs.

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CVS Intallation

• Installation for Windows
• Installer can be found on http//www.wincvs.org
• WinCVS also requires download CVSNT which comes
  included in the install
• package,
• however it can be downloaded separately
• There are 3 different package you can download
• Development
• The most up to date releases
• Least Tested
• Not recommended for production environment
• Recommended
• Development builds become Recommended when no
  serious issues get reported with them
• Most Stable
• Recommended for novice users and in critical
  environments
• Milestone
• feature-complete and sufficiently stable
• No further development will be done unless
  serious issues arise

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CVS Installation continued

• As the name suggests, recommended builds are
  ideal for production environments
• Installation on Mac and Linux/Unix
• Mac Version can also be found on
• http//www.wincvs.org
• Linux version can be found on
• http//ftp.gnu.org/non-gnu/cvs/
• Instructions for installing CVS on Linux can be
  found here
• http//www.devguy.com/fp/cfgmgmt/cvs/cvs_admin_lin
  ux.htm

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Subversion Installation

• Subversion is built on a portability layer called
  APR (the Apache Portable Runtime library)
• This means Subversion should work on any
  operating system that the Apache httpd server
  runs on Windows, Linux, all variations of BSD,
  Mac OS X, Netware, and others.
• The easiest way to get Subversion is to download
  a binary package built for your operating system.
  
• Subversion's website (http//subversion.tigris.org
  ) Alternately, you can build Subversion directly
  from source code.
• Requirements
• APR (the Apache Portable Runtime library)
• Apache HTTP Server (optional)
• Berkeley DB (optional, but strongly recommended)

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Conclusion

• Version Control is an essential part of a team
  development environment, allowing the whole team
  to work on the project at the same time.
• CVS vs. Subversion
• It is a matter of personal preference however CVS
  is more well-known and therefore, possibly has a
  better support network.
• http//www.nongnu.org/cvs/
• http//www.wincvs.com
• http//ximbiot.com/cvs/cvshome/
• http//ftp.gnu.org/non-gnu/cvs/
• http//svnbook.red-bean.com/
• http//subversion.tigris.org/

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All Information Obtained From

• http//www.nongnu.org/cvs/
• http//www.wincvs.com
• http//ximbiot.com/cvs/cvshome/
• http//ftp.gnu.org/non-gnu/cvs/
• http//svnbook.red-bean.com/
• http//subversion.tigris.org/