The web technology - CGI

In the old days, web servers were serving static content only, that is, when a browser requests www.example.com/mypage.html, there is actually a file named mypage.html and the server will fetch the page and return it to the client in its response.

Then people want more dynamic stuff and CGI is the first solution. When a browser requests example.com/cgi-bin/myscript.pl, the server is not returning the script itself, instead, the server will run myscript.pl and send back the output. The binary/script is normally put in a directory called cgi-bin, and perl is a popular language to write that script. However, you can put anything in cgi-bin, anything executable, for example, a c++ binary, provided that the server knows how to execute it.

This approach launches a separate process for each request and has several consequences. Forking a process and then shut it down is expensive, especially when the actual computation is cheap and quick.

Competing technologies available, Java servlet, Microsoft ASP.