Distributed version control Facts for Kids

A distributed version control system (often called DVCS) is a smart way to manage changes in computer code. Imagine you're building a huge LEGO castle with friends. Instead of one central instruction book that everyone shares, each of you gets your own complete copy of the instructions, including every change ever made!

This means every developer has a full copy of the project's code and its entire history on their own computer. This makes it easier to work offline and speeds up many tasks. It also means there isn't just one main copy, so if something happens to one computer, the project is still safe on others. Git, the most popular system for managing code changes today, is a distributed version control system.

How DVCS is Different from Centralized Systems
- Benefits of Using DVCS
- Challenges of Using DVCS
How Teams Work with DVCS
- Main and Branch Copies
- Pull Requests: Sharing Your Work
History of DVCS
See also

How DVCS is Different from Centralized Systems

Distributed version control systems work like a team where everyone is equal (this is called a peer-to-peer approach). This is different from older systems that use a main server (a client-server approach).

In a DVCS, there's no single "master" copy of the code. Instead, each person working on the project has their own full copy of the code and all its past changes. When someone makes a change, they can share it directly with others.

Benefits of Using DVCS

DVCS has many cool advantages:

Work Anywhere: You can work on the code even if you're not connected to the internet.
Super Fast: Tasks like saving your changes or looking at the project's history are much quicker. This is because you don't need to talk to a central server all the time.
Private Work: You can make changes and save them to your own copy without sharing them with everyone right away. This is great for trying out new ideas.
Built-in Backups: Since everyone has a full copy, it's like having many backups. If one computer has a problem, the code is safe on others.
Flexible Teamwork: It allows different ways for teams to work together, which is great for big projects like the Linux kernel.
Easy to Branch Off: If a project gets stuck or people disagree, it's much easier to create a new version of the project (called a "fork").

Challenges of Using DVCS

Even with all its benefits, DVCS has a few challenges:

First Download Takes Longer: When you first get a project, it takes a bit longer because you're downloading the entire history, not just the latest version.
More Storage Needed: Each person needs more space on their computer because they have a complete copy of the project's history.

Some older, centralized systems are now adding features that make them more like DVCS. Also, some distributed systems are finding ways to make the first download faster and use less storage.

How Teams Work with DVCS

The distributed model is great for big projects where many developers work on different parts at the same time. Think of a huge open-source project like the Linux operating system. Developers can work on their own parts and then offer their changes to be added to the main project.

Developers can make a copy (or "clone") of the entire project history onto their own computers. They save their changes to their local copy first. Later, when they are ready, they "push" their changes to the main project. This way, teams can work from anywhere, even if they are not connected to the internet.

Main and Branch Copies

In some truly distributed projects, like Linux, every person might keep their own version of the project. They can share changes with each other, and a common version slowly forms from everyone's contributions. This also makes it very easy to "fork" a project, which means creating a new, separate version of it.

However, many projects choose to have one main "official" copy of the code. This main copy is managed by the project's leaders. New developers usually copy this official version to start. They then work on their local copy and regularly update it with changes from the official version. Once their work is done, their changes are added back to the official copy.

Many organizations use services like GitHub to host their main project copies. These services offer reliable access and extra tools like ways to track issues or automatically test code.

Pull Requests: Sharing Your Work

When a developer wants to add their changes to a project using a DVCS, they usually create a pull request (sometimes called a merge request). This is like saying, "Hey, project maintainers, I've made some cool changes. Can you 'pull' them into the main project?"

The pull request lets the maintainers see all the changes. There's usually a place for comments, so people can discuss the new code. Anyone with access to the project can see these requests. The maintainers then decide if they want to accept or reject the changes.

If the changes are approved, they are "merged" into the main project. Sometimes, the code needs to be tested first. Some projects have a special area for untested changes. Other projects use automated tools to test every pull request to make sure the new code works well.

History of DVCS

The first open-source distributed version control systems included Arch, Monotone, and Darcs. But they didn't become very popular until Git and Mercurial came along.

BitKeeper was used for the development of the Linux kernel from 2002 to 2005. The company that made BitKeeper later stopped offering a free license to the Linux developers. This led Linus Torvalds, the creator of Linux, to develop Git, which is now the most popular version control system in the world.

Distributed version control facts for kids

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