Git is a software that keeps track of changes and allows you to move back and forth between different versions to compare and see what changed between each one. Git is a VCS (Version Control System). When a VCS is used to manage source code, it’s also called a SCM (Source code management) too
VCS + source code = SCM
Let’s look back
Source Code Control System (
SCCS) 1972. Closed source, free, Only for UNIX.
It stored the original file and all the changes that went after it, so when you opened the file, it opened the original one and then all the changes were applied (low performance)
Revision Control System (
RCS) 1982. open source, cross platform.
It kept the most recent file in its whole form with all the previous changes, and only if you want a previous version, you applied the change snapshot to go backwards in time (better performance)
Concurrent Version System (
CVS) 1986. Open source, cross platform. You could work with multiple files.
Many users could work with a single repository over a network, the concept of remote repositories were introduced.
Apache Subversion (
SVN) 2000. Open source, cross platform. It was faster and allowed to save different file formats.
It kept track of directories not only of files, SVN applied transactions to update changes through many files and directories and mantain integrity
Bitkeeper scm 2000. Closed source, cross platform.
First distributed versions control, it had a community version used for source code of the Linux kernel. In 2005 the community version disappeared
Git 2005. Open source, cross platform. Developed by Linus Torvalds as a replacement for Bitkeeper
Distributed Version Control
Every user maintain their own repositories. Changes are stored as change sets or patches and every user tracks only the changes that are useful for them.
It is a convention to establish a “master” repository and stay up to date with this master repository, but it is just a convention, we don’t have to
No need to communicate with the central server (work offline), it allows you to work independently and then submit your changes for inclusion or rejection
