Mr. Lerner introduces us to server-side includes.
Most web sites contain largely static HTML files jazzed up with some images.
More advanced sites use one or more CGI programs, HTTP cookies, database backends and other topics we have discussed in previous months. All of these techniques involve creating at least one new process on the web server. If we are interested in keeping our server's load as low as possible, we should avoid creating unnecessary processes. SSIs offer a good balance between efficiency and complexity. Even if you have never seen them, server-side includes are pretty easy to understand.