A great read from Wired.
To the surprise of many, the foundation of Facebook is built using a computer programming language called PHP. With over one billion members and growing, most experts believe this to be a bad move, since PHP is not suited for huge websites such as Facebook. The challenge was to find a way to rebuild the Facebook foundation without changing the whole code to a new language like C++. Three engineers accepted the challenge.
“Rather than translate PHP into C++, they would convert it into native machine code — the language spoken by the chips at the heart of the company’s servers — and they would do this as the code was executing. By tracking the way the site executed in real-time, they could get a better idea of how it should be translated into machine code — and this would ultimately speed things up.”
Read the rest here