Many people have asked what we did that was so special. We used a Kernel Mode Accellerator to allow the server to handle high traffic much more effectively.
When a surfer requests a file, normally, the Operating system takes the incoming request in Kernel Mode, switches to User Mode and hands Apache the request. On a very busy server, these context switches get in the way of server performance.
What a Kernel Mode content accellerator does is remove that context switch on content that it can serve. Of course, dynamic content shouldn't be served from the kernel, but static html, images and movie content can easily be delivered because they don't require any preprocessing before the data is sent. Since the kernel itself is already handling the incoming connection, and it doesn't need to hand off the connection to another process, the server eliminates quite a bit of overhead. Also, the kernel uses lower level filesystem requests, resulting in even faster performance.
An interesting side effect is that until the server is really busy, the time savings isn't easily detected. But once the server gets busy, it will continue to perform well, and scale much better than any other platform.
Rest assured, even though the web serving is done through the kernel, there are strict configuration options that prevent many types of hack attempts. If the Kernel Mode Accellerator detects anything fishy, it hands it off to the backend user-mode process, severely limiting the ability for anything to exploit the server. The accellerator never trusts any data sent to it from the outside - all it does is serve data from the local disk to the client as quickly as possible.
Fast, Simple, Secure.