With the fast growth of virtualized data centers, and companies like Google, Amazon & Facebook, it's easy to forget how much is built on open-source components, aka commodity software. In a very real way open-source has enabled the huge explosion of commodity hardware, the fast growth of the internet itself, and now the further acceleration through cloud services, cloud infrastructure, and virtualization of data centers.
Your typical internet stack and application now stands on the shoulders of tens of thousands of open source developers and projects. Let's look at a few of them.
1. Operating System - Linux
The commodity hardware craze would never have happened without the help of an open-source operating system to run on it. Linux is an old story now, nonetheless everything else stands on it's shoulders.
2. Multi-purpose Webserver - Apache
As of July of 2011, Apache stands with 66% of the webserver market, above Microsoft IIS with 17% according to Netcraft. That speaks volumes about the popularity of the open source webserver. All sorts of applications and languages use the apache webserver as the way to serve up content on the internet. In effect there is a 66% chance that your browser is talking to Apache for any given site you visit.
3. Multi-purpose Relational Database - MySQL
Back in the late 90's we worked at tons of internet startups. They all used Apache on the frontend and Oracle on the backend. These days we rarely here of internet sites aka web-facing databases on Oracle. That's because MySQL has matured quite a lot in the past decade, and now provides all of the basic bells and whistles that a complex internet site requires. Transactions, crash protection, high availability features, and data integrity.
4.Content Management System - Drupal, Django, WordPress, Joomla
The growth and popularity of open-source CMS systems is also evident. Although much of what they do can and has been built from scratch, they enable a better starting point, providing you a strong framework around which to build a full-feature and scalable site.
5. Languages and Frameworks - PHP, Perl, Ruby on Rails
Let's not forget the languages and frameworks that all of these web applications are written in. PHP with it's very DIY evolution, has grown to fill the needs of real developers. With tons of community development, contributions and support, it also is illustrative of what open-source has brought to the web.