From PHP/FI to PHP 5! The Evolution of PHP

We all know that PHP is a widely used server side scripting language. Nowadays it is used even as a general purpose programming language. A recent survey says that, PHP is installed on more than 244 Million websites and 2.1 Million servers worldwide. No wonder PHP is considered a must learn topic for all web developers. You may be strong with some of the concepts in PHP but have you wondered how PHP evolved from the classical acronym of Personal Home Page to the present matured programming language with the recursive acronym PHP: Hypertext Preprocessor. PHP/FI The PHP of today’s world is the successor of PHP/FI. In 1994, PHP was created as a simple set of Common Gateway Interface (CGI) by Rasmus Lerdorf. It was just a set of binaries written in C language. The purpose Rasmus wrote these binaries were to track the visits to his online personal resume. Hence he named the set of scripts as “Personal Homepage” referred to as PHP Tools. Over the time, to improve the functionality he rewrote PHP Tools producing a much larger and richer implementation. With this new model he had incorporated database connectivity and more. The new version served as a framework upon which developers could create simple dynamic web applications. During June of 1995, Rasmus released the source code to public thus enabling developers to add to it. Not just that, this release permitted and encouraged developers around the world to provide fixes for bugs and also improve the source code as a whole. By September of 1995, Rasmus dropped the name PHP and named the set of tools as Forms Interpreter (FI). This was the very first version that had a similarity to the present day PHP. It had Perl-like variables, automatic interpretation of form variables, and HTML embedded syntax. The syntax was very similar to that of Perl but was somewhat inconsistent. In fact, to embed the code into an HTML file, developers had to use HTML comments. Though this method was not entirely well-received, FI continued to enjoy growth and acceptance as a CGI too, but still not quite as a language. By April of 1996, the source code got a complete makeover again. Combining the names of the last two releases Rasmus named it PHP/FI. This is the stage where PHP started evolving as a language rather than a simple set of CGI Tools. The second generation PHP had support for DBM, SQL, and Postgres95 databases, cookies and support for user-defined functions. By June of 1996, PHP was given the version 2 status. By 1998, PHP had several thousand users around the world and was gaining popularity exponentially. A Netcraft survey as of May, 1998, indicated that nearly 60,000 domains reported containing PHP modules in them. This is approximately equivalent to 1% of all domains on the internet at that time. PHP 3 PHP 3 was a version that had the shape of PHP used today. This version evolved because the functionalities PHP/FI wasn’t sufficient to power an eCommerce application. Now you will find it hard to accept that as most of the eCommerce applications today are written using PHP. This was the turning point which matured PHP. The change was brought about by two young developers Andi Gutmans and Zeev Suraski of Tel Aviv, Israel who were doing a University Project. In 1997 they began a complete rewrite of the underlying parser. They contacted Rasmus online and in a combined effort they strengthened the basic engine, building upon PHP/FI to build an independent programming language. The old name (PHP/FI) was dropped and this entirely new programming language was given a recursive abbreviation of PHP meaning PHP: Hypertext Processor. The biggest strength of PHP 3.0 was its extensibility features proving a mature interface for different protocols, databases and APIs. Another major factor for the success of PHP 3 was that it supported object-oriented programming and it had a powerful and consistent syntax. By June 1998, many developers around the world joined in for the development of the new open-source language PHP. After approximately 9 months of public testing by the time PHP 3 was officially released it was already installed on around 10% of servers around the world. PHP 4 By December 1998, Andi and Zeev started rewriting the core of PHP 3. It wasn’t long before PHP 3 was released, but their desire to make PHP a mature language made them do so. Though PHP 3 had a rich array of features and support for many third party tools, it couldn’t handle complex applications efficiently. This was one of the major problems addressed by PHP 4. The new engine for PHP 4 was called “ZEND Engine”, named after the first name of the authors Zeev and Andi. PHP 4 was officially released on May of Y2K. In addition to the highly improved performance of this version, PHP 4.0 gifted other key features such as support for many more web servers, HTTP sessions, output buffering, more secure ways of handling user input and several new languages constructs to the millennium. PHP 5 Already a mature language by PHP 4, PHP 5 was a sophisticated upgrade to its predecessor. The core was modified as Zend Engine 2.0 imprinted with new object models and a big bundle of new features. Some of the notable features that impressed developers around world to migrate to PHP 5 were pass by reference, visibility parameters, unified contractors and developers, abstract classes, interfaces, magic methods, finality and the __autoload function. PHP 5 with it present 5.4.15 had become a robust language. As of January 2013, as per the survey by Netstat – 244 Million websites are using PHP. I don’t think any another statistic is required to show the power of PHP. And not just that, the active PHP community around the world is working tirelessly to improve the language and PHP 5.5.0RC2 is already available for download.