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Section 1.1.  PHP History

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1.1. PHP History

Contrary to what some might have you believe, there was a lot of activity on the web development front before PHP was invented. Prior to its invention, code for server-side scripting was usually written in C or Perl, both of which are general programming languages that were adapted to use on the Internet.

The original PHP release was created by Rasmus Lerdorf in June 1995, to make various common web programming tasks easier and less repetitive. The name originally stood for "Personal Home Page," but has since become a recursive acronym, standing for "PHP: Hypertext Preprocessor." The goal of that release was to minimize the amount of code required to achieve results, which led to PHP being HTML-centricthat is, PHP code was embedded inside HTML.

The second PHP release, known as PHP/FI 2.0, was the first to achieve widespread popularity, and despite the parsing inconsistencies, it managed to attract a few converts.

The release of PHP 3 was largely driven by Zeev Suraski and Andi Gutmans, who rewrote PHP from the ground up and removed the parsing problems. PHP 3 also made it much easier for others to extend the languageparticularly keen developers could now easily write their own modules for the language, adding functionality at the core level.

With PHP 3, the language had also gained limited object-oriented support, and this added extra fuel to the fire of PHP's growth. By the time PHP 3 was replaced in the middle of 2000, it was installed on over 2.5 million web site domains, as compared to 250,000 just 18 months before. Its successor, PHP 4, contained numerous major changes, including the switch to what is called the Zend Engine .

Zend is a company founded by Zeev Suraski and Andi Gutmans to promote PHP in the corporate environment, and the engine they produced brought with it numerous advantages. By taking over the core of PHP, the Zend Engine introduced reference counting to ensure there were no memory leaks; introduced web server abstraction so that PHP ran on Apache 1.3.x, Apache 2, Microsoft's IIS, Zeus, AOLServer, and more; and also changed the way that PHP code was executed so that code was read once, converted to an internal format, then executed. This new execution paradigm allowed the use of external code caches, also known as PHP accelerators, that further boost performance.

Although not as vast as the jump from PHP 3 to PHP 4, the move from PHP 4 to PHP 5 is still a big one. Along with hugely improved object orientation, the addition of try/catch error handling, and exceptions, there are two major new extensions: SimpleXML, a fast and easy-to-learn way to interact with XML documents, and SQLite, a new flat-file database API that eases the burden of deploying simple database solutions.


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