The version library is centralized on a central server. When we actually work, we use our own computers, so we must first connect to the central server to get the latest version from there, then write or change the code, and after finishing, we need to push the work we have done to the central server. Centralized version control systems must be connected to the Internet to work. If it is in a local area network, it is OK, the bandwidth is large enough, and the speed is fast enough. If it is on the Internet, if the speed is slow, it will be very depressing.
For friends who have worked on big data (Hadoop) or large databases, the concept of "distributed" must be very familiar, so I won't explain it too much here. Compared with centralized version control systems, distributed control systems do not have a central server. Everyone's computer is a complete version library, so there is no need to connect to the Internet when working, because the versions are all on their own computers. Since everyone's computer has a complete version library. Then the question is, how to collaborate on project development among multiple people? For example, someone modifies file A on his computer, and at the same time, someone else also modifies file A on his computer. At this point, you two only need to push your own changes to each other, and you can see each other's changes.
If you have used SVN and Git, it is not difficult to draw a conclusion: SVN belongs to a centralized version control system, while Git belongs to a distributed control system.
