Web Server vs Application Server
A computer (or a computer program) that runs a program dedicated for the acceptance of HTTP requests from clients and serves back HTTP responses such as web pages in HTML and other linked objects, is called a Web server. On the other hand, a software engine that will provide different applications to another device is called an Application Server. They are usually found in offices and universities, and they allow all users in the network to execute software applications off of the same machine. But, due to the expansion of Internet and Web 2.0 technologies, both web server and application server are beginning to blur in to each other very rapidly. Furthermore, an application server can be configured to work as a web server too.
What is Web Server?
Web Server, as the name suggests, mainly functions to keep serving web pages twenty-four hours, seven days a week. As long as the web server is up and running, the corresponding web pages and sites will be available to the users over the network. Therefore, it is very important that a web server is working all the time so that it may not cause the user any inconvenience due to the unavailability of the web pages. The downtime is used to define any time lost due to the website and its pages being unavailable. Reputed web hosting companies try to maintain a good service, which means there should be a minimum downtime such as less than a fraction of a second. Typically, web servers do not support multi-threading. Web servers do not have connection-pooling, isolation-pooling and transaction features as well. In order to understand the concept of web servers more clearly, consider the following scenario. The user who wants to visit www.cnn.com types the address on Internet Explorer (i.e. a web browser), which is actually running on the client’s machine. Then, this request is sent to the cnn web server that which is actually keeping these pages in its hard-drive. Web server then send the content of the page and other linked objects back as a response to the web browser and the web browser displays these to the user. So, it goes without saying that a web server needs to serve request quickly from more than one connection at a time.
What is Application Server?
An application server can be treated as a software framework, which provides an environment where many applications can be run regardless of what they are. Downtime is important also for application servers as well. For the best service, you need to maintain a downtime of less than a fraction of second. Typically, an application server supports multi-threading. You find features like isolation pooling and connection pooling and the transaction feature in application servers. Because application servers run different software that may depend on other software and applications, they usually bundle middleware to enable intercommunications with depended applications like web servers, database management systems and chart programs.
Difference Between Web Server and Application Server
Although the distinction between the web server and the application server is deteriorating rapidly, there are some key differences between a web server and an application server. A web server can typically handle a limited number of requests but application servers have a much higher capacity. Unlike web servers, application servers support multi-threading, transactions and mechanisms like connection pooling. Web servers support to deploy .war files while application servers support to deploy .war and .ear files. Furthermore, application servers have integrated middleware to communicate with other applications, as opposed to web servers.