The document compares centralized version control systems (CVCS) and distributed version control systems (DVCS), outlining their functionalities, advantages, and disadvantages. CVCS relies on a central server for collaboration while DVCS allows each user to maintain a complete repository locally, enabling efficient changes and faster performance. Additionally, it discusses the monorepo and multirepo approaches to code management, highlighting their respective benefits and challenges.

1. Centralized
and
Distributed
Version
Control
System

2. Local Version Control
Module Objectives
1
Distributed VCS
3
Centralized VCS
2
Comparison between CVCS
and DVCS
4

3. Local Repository
 Local version control keeps track of the
files within the local system.
 It saves a series of patches, but
collaboration or branching is almost
impossible with local repositories.
 A local repository, from a DVCS
viewpoint is a collection of files which
originates from a certain version of the
repository.

4. Centralized Version Control System (CVCS)
 CVCS systems keep a single copy of the project on
a central server and the developers commit their
changes to this central copy of the project.
 Updates to the code is recorded in the central
system; when developers pull the code, changes are
automatically applied to the files that were changed
and developers pull this updated version.
 CVCS eliminate the need to keep multiple copied of
their files on their hard drives.
 Examples: CVS, Subversion, Preforce

5. Distributed Version Control System (DVCS)
• DVCS replicates the repository onto each
user’s machine, i.e. each user has a self-
contained first-class repository.
• There is no need for a privileged master
repository, though teams have it by
convention, for doing continuous
integration.

6. Features of Distributed Version Control System
• Private workspace
• Easier merging
• Easy to scale horizontally

7. Advantages of Distributed Version Control System
• Other than push and pull, all actions can be performed very quickly, since it is the hard drive and not the
remote server that is accessed every time.
• Changesets can be committed to local repository first and than a group of these changesets can be pushed to
the central repository in a single shot.
• Only push and pull need internet connectivity.
• Every developer has a complete copy of the entire repository and the impact any change can be checked locally
before the code is pushed to the central repository.
• DVCS is built to handle changes efficiently, since every change has a Global Unique Identifier (GUID) that makes it
easy to track.
• Branching and merging is easy.
• DVCS is easy to manage as compared to CVCS

8. Disadvantages of Distributed Version Control System
• It may not always be obvious who did the most recent change
• File locking doesn’t allow different developers to work on the same piece of code simultaneously. It helps to
avoid merge conflicts, but slows down development
• DVCS enables you to clone the repository – this could mean a security issue
• Managing non-mergeable files is contrary to the DVCS concept.
• If your project contains many large, binary files that cannot be easily compressed, the space needed to store all
versions of these files can accumulate quickly.
• If your project has a very long history (50,000 changesets or more), downloading the entire history can take an
impractical amount of time and disk space.

9. CVCS vs DVCS

10. CVCS vs DVCS

11. CVCS vs DVCS

12. Monorepo
• The monorepo approach uses a single repository
to host all the code for the multiple libraries or
services composing a company’s projects.
• The whole codebase from a company - spanning
various projects and coded in different languages
— is hosted in a single repository.
Multirepo
• The multi-repo approach uses several
repositories to host the multiple libraries or
services of a project developed by a company.
• It’ll host every minimum set of reusable code or
standalone functionality (such as a
microservice) under its repository.

14. Monorepo
• Lowers Barriers of Entry
• Centrally Located Code Management
• Painless Application-Wide Refactoring
• More Difficult To Break Adjacent Functionality
• Teams Share Development Culture
Multirepo
• Independent Library Versioning
• Independent Service Releases
• Helps Define Access Control Across the
Organization
• Allows Teams To Work Autonomously
Benefits

15. Monorepo
• Slower Development Cycles
• Requires Download of Entire Codebase
• Unmodified Libraries May Be Newly Versioned
• Forking Is More Difficult
Multirepo
• Libraries Must Constantly Be Resynced
• May Fragment Teams
Issues

16. Useful Links:
• https://www.toolsqa.com/git/git-tutorial/
• https://www.atlassian.com/git/tutorials
• https://www.edureka.co/blog/interview-questions/git-interview-questions/