Understanding Page Requests

When you create a Web application, the application will be hosted on a web server. This is the place where your Visual Basic compiled code actually resides. When the code is executed, the ASP.NET engine renders it as HTML so that it can be consumed on the client side by a web browser such as Internet Explorer and Fireox, which can interpret HTML and display web pages. When you type a website address into your browser, it sends a web page request. This is then translated into an address that searches for the server hosting the requested page. When the server receives the request, the installed web server software catches the request and, if this is about an ASP.NET web page, passes the request to the ASP.NET engine so that this can render the result as HTML and return it to the calling browser. Samples of web server software are Internet Information Services (IIS) and the Cassini Web Server. Visual Studio 2010 ships with its own web server, named ASP.NET Development Server, which enables simulating a web server environment on the development machine for testing applications. But you do not write HTML, whereas you write Visual Basic code that is compiled into an assembly residing on the server; so the ASP.NET engine sends requests to your code for processing and then it returns the processing result as HTML that can be consumed by client browsers. All these operations are fine, but there is a problem: In a desktop environment you have one user running one instance of the application that works against its set of data and information; even if you have hundreds of database records to load, the application will be responsive in most cases. The same is not true for web applications if you think that one Web application hosted on a server could potentially receive hundreds of concurrent requests; therefore, elaborating hundreds of data requests concurrently can cause a bottleneck with hard performances problems. Fortunately ASP.NET provides a mechanism for scalability that lets the application solve performance problems the best way possible.