Describing types of source control systems
Centrailized source control
- Based on the idea that there's a single "central" copy of project somewhere (like server).
- Programmers check in (commit) their changes to central copy.
- Version control tool can talk to the central copy and retrieve any version they need on the fly.
Most popular centralized version control systems are:
- Team Foundation Version Control (TFVC),
- CVS,
- Subversion (SVN),
- Perforce.
| Strengths | Best used for |
|---|---|
| Easily scales for very large codebases | Large integrated codebases. |
| Granual permission control | Audit & Access control down to a file level. |
| Permits monitoring of usage | Hard to merge file types. |
| Allows exclusive file locking | - |
Typical centralized source control workflow
- Get the latest changes other people have made from the central server.
- Make your changes and make sure they work correctly.
- Check in your changes to the main server so that other programmers can see them.
Distributed source control
Most popular distributed version control systems:
- Git,
- Mercurial,
- Bazaar.
| Strengths | Best used for |
|---|---|
| Cross Platform support | Small & Modular codebases. |
| An open source friendly code review model via pull requests | Evolving through open source. |
| Complete offline support | Highly distributed teams. |
| Portable history | Teams woring accross platforms. |
| An enthusiastic growing user base | Greenfield codebases. |
Advantages over centralized source control
- Doing actions other than pushing and pulling changesets is fast because the tool only needs to access the local storage, not a remote server.
- Committing new changesets can be done locally without anyone else seeing them. Once you have a group of changesets ready, you can push all of them at once.
- Everything but pushing and pulling can be done without an internet connection. So, you can work on a plane, and you won't be forced to commit several bug fixes as one large changeset.
- Since each programmer has a full copy of the project repository, they can share changes with one, or two other people to get feedback before showing the changes to everyone.
Disdvantages over centralized source control
- If your project contains many large, binary files that can't be efficiently compressed, the space needed to store all versions of these files can accumulate quickly.
- If your project has a long history (50,000 changesets or more), downloading the entire history can take an impractical amount of time and disk space.