Almost everyone has heard of web servers but most people don’t actually know what they are! In a certain sense a spider is a web server but that is not the kind of web server we have in mind. This article explains in simple terms what an internet web server is and also explains why they are so important for the efficient functioning of modern websites. The most common type in use today is probably Apache. It is a software application but it runs on a physical hardware device (or server). So when someone speaks about a web server they usually mean both the hardware device and the software that is running on it. Lets look at how these servers typically work:
* first you enter the address of a web page in your browser, say Amazon or eBay
* your browser sends a page request to the web server at the address you provided (its like a street address)
*the Amazon or eBay server intercepts your page request
*if the the server does indeed have the page you requested then it will return the page to your browser
*you see the page that you requested appear in your browser as if by magic 🙂
The above description is a simplified view of a web server but it does the job of explaining how they work. However lets look at a more complex scenario. This is when the server sits in front of many other servers. The reason for this is that if a website receives lots of traffic (I wish) then if only one server is used it will quickly get overworked and grind tro a halt. This results in great gnashing of teeth and frustration as we switch our attention to an alternative web site to find what we were looking for. However if there are lots of servers who can answer our request it is unlikely that any one server will get overworked. The key is to make sure that the requests are shared amongst the available servers. This is were our web server comes to the rescue again. One single server sitting in front of the other servers (or back-end servers) can intercept our page requests and instead of trying to do all the work itself it shares the requests with the other servers who instead do all the work involved in returning the requested page (this is called load balancing). This in turn leads to happy web surfers as we usually get a quick response to our page request.