The Evolution of Version Control Systems: Before Git

Version control systems have been integral to software development for decades. Before the widespread adoption of Git, developers relied on a variety of systems to manage their codebases. This article delves into the evolution of these systems, focusing on Source Code Control System (SCCS), Revision Control System (RCS), and Subversion (SVN). We'll also explore the context and factors that led to the creation of Git.

Early Days of Version Control

In the 1950s, 60s, and 70s, developers managed their code through various means, ranging from implementing their own custom systems to using shared storage solutions. This approach was often ad hoc and lacked the sophistication of modern version control systems.

Source Code Control System (SCCS), one of the earliest VCS (Version Control System) products, was developed in the early 1970s. SCCS laid the groundwork for future systems but was not widely adopted beyond Unix-based environments.

Branching and Merging with RCS

Revision Control System (RCS) was an expansion on SCCS, introducing features like branching and merging. While RCS was a significant improvement, it still relied on centralized control, much like Subversion (SVN) and CVS (Concurrent Versions System).

Centralized Systems

SVN (Subversion) and Perforce are examples of centralized version control systems. These systems require a central repository for storing and managing all versions of files. SVN, in particular, became very popular, especially with the rise of SourceForge as a hosting platform for open-source projects.

Decentralized and Distributed Systems

Before Git, there were some decentralized systems, but they saw limited use. The introduction of Git and Mercurial marked a significant shift towards distributed version control systems (DVCS). These systems allowed developers to work with local repositories and sync changes with a central repository when necessary.

Why Linus Torvalds Created Git

According to the history, Linus Torvalds created Git primarily due to a licensing issue with BitKeeper, a popular SCM (Source Control Management) tool. Torvalds was dissatisfied with BitKeeper's licensing terms and decided to create his own version control system, hence the name "Git." The name is a self-deprecating reference to himself, as "git" in English can mean an arrogant or sassy person.

Convergence of Git

As version control systems evolved, many features converged on Git. One of the key benefits of Git is its ability to handle multiple branches, making it more flexible and user-friendly. Git's distributed nature also allows developers to work offline and sync changes later, making it suitable for modern software development.

Highlighted VCS Products

Below are some prominent version control systems from the past:

SCCS (Source Code Control System) - A pioneer in the version control system concept. RCS (Revision Control System) - Introduced branching and merging, improving upon SCCS. PVCS (Productivity Version Control System) - Born in 1985, it's one of the oldest fully functional products, known for its file locking features. CVS-SVN (Concurrent Versions System - Subversion) - Top contenders in CVCS (Centralized Version Control System) rivalry, with SVN eventually becoming the leader due to its improvements in atomic commits, better branching, and merging.

Conclusion

The evolution of version control systems has been driven by the needs of developers and the challenges they face. From early ad-hoc systems to centralized and finally distributed systems, each iteration brought new features and capabilities. Today, Git stands as the dominant player, driving innovation and continuing to shape the way we manage code.