The CVS Version Control System Explained

During December 1986, Dick Grune released a bunch of shell scripts by posting it to newsgroup comp.sources.unix. It contained many of the conflict resolution algorithms used in software that had been useful for many programmers for decades. This software was called CVS version control.

What is CVS version control?

Concurrent Version System (CVS) is open source software that records the history of your documents and source code. It tracks all changes in your files and saves all revisions without taking up too much disk space. It was originally built for programmers working on computer source code, as sometimes a bug is introduced when a certain modification is done on the software they are working on. However, by using CVS (or other version control systems such as Subversion and Git that have been developed since), they can easily restore the previous revisions of their files to determine what changes introduced the bug.

What are the benefits that you can gain from using CVS?

CVS version control is free, downloadable, and is easy to install and understand. Using CVS version control allows you to work on a file system using several machines. For example, you are working on a source code on your personal computer. You can access the repository using another computer and make local copies of the files. When you are finished editing the file, you can commit it back to the repository, and the CVS version control updates the file. CVS help prevent source trees from getting out of sync, hence preventing much confusion.

Also, CVS version control is a great tool for large projects with multiple users. It enables users to work on a single file and make edits to such file at the same time. The users save a local copy of the file and make their modifications. When they are finished making the necessary changes, they commit the files back into the repository. The users have an option to merge their files individually, then CVS merges all the changes to one final file. In case there are problems that arise from merging the file, the software alerts the users to make corresponding decisions.

CVS is also recommended for users with a slow Internet connection. They can simply make local copies of the files from the repository and edit them offline. When they are finished, they can connect to the Internet and CVS will sync the files.

What are the problems you can encounter with CVS?

Though CVS version control might be useful in some instances, it also has a number of limitations. CVS is a mature technology and lacks some functionality that newer version control tools have. For instance, CVS version control is not capable of atomic operation support, which prevents corruption of the source code should the network connection be interrupted. An atomic operation is a sequence of instructions that is guaranteed to be executed in succession, without any disruption, or not at all. An interrupted CVS connection may result in partial commits..

CVS also contains some security risks from symbolic links to files, and has not been updated since 2008. Moving or renaming files in CVS also does not include a version update, and branch operations in CVS are expensive, as CVS is not designed for long term branching.

Nowadays, CVS version is replaced by Subversion (SVN), which was originally made as an alternative to CVS. It fixes many of the bugs and issues inherent in the CVS system while maintaining high compatibility with it. Unlike CVS, SVN employs atomic operations which prevent corruption in the database.

Version Control

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