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Something else I want to mention is that there

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are many different version control systems but we can classify

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them normally in two main types: centralized VCS's and

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decentralized VCS's. So what is the difference between these two?

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Let's use again our friends Janet and Brett.

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In the case of a centralized version control system

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there is a single centralized, as the name says,

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repository. On which they are commiting their files. So when

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Janet commits a file. The file will go from

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her local working directory to the repository, and the same

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will happen to Brett. The decentralized system is a little

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more interesting because in this case, they will both have

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sort of a local repository in which they can commit

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their changes. So they can commit changes without the other

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users of the VCS being able to see these changes.

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And when they're happy with the version. And when they're

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ready to release the version, they can push it to a central

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repository. And at that point, it will become available to the other

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users of the repository. To the other users of the VCS. There

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are several advantages in a distributive

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system. I'm just going to mention a few,

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because there are really many. One is the fact of having this

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local version. If you used VCS before, I'm sure you've been in

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the situation in which you want to kind of take a snapshot

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of what you have. But you don't want that snapshot to be available

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to the other users. Because it's still not ready to be

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released, to be looked up. If you're using a centralized system,

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there's really no way you can do that, unless you make

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a local copy, which is something we said you don't want

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to do. With a distributor, with a decentralized VCS you can

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commit your local changes here, in your local repository, and you

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can push them to the central repository only when you're ready.

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Another big advantage, is that you can use multiple remote repository.

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In fact, centralized is not the right name for this

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one. This is just a remote repository, and I can have

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more than one. For example, Brad might want to push

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to another remote repository. As well. For instance, this could be

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a repository where the files are accessible for wider distribution.

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Imagine developing a software system in which a team is sharing

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internal versions, and then only some of these versions are actually

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pushed to the repository that is seeable to the whole world.