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Oct 28, 2012

Asp.Net Tutorial (PART-3)

History of ASP

You can trace the history of ASP right back to 1995 and the momentous occasion when Microsoft realized they were falling behind in a fundamental shift in the industry by not embracing the Internet. Up until that point Microsoft had been developing their proprietary technologies, tools, and network protocols for the Microsoft Network; all of a sudden they needed an Internet strategy and fast.

Microsoft has gone from a position of playing catch-up to one close to dominance, with the Internet Explorer Web browser having a strangle-hold on the Web browsing market, and Internet Information Server (IIS) installed at the majority of Fortune 1000 companies.

The Origins of ASP

Back in the mid 90s, when the commercial Web world was still young, there was not a great deal of choice of tools for the Web developer who wanted to make his or her Web site a truly useful place to do business.The choices were limited in both available server-side programming platforms and also desktop development tools to produce the solutions. In the end, the programmer was stuck with clumsy Common Gateway Interface (CGI) programs using compiled languages such as C, Delphi, and Visual Basic, or interpreted scripting languages like Perl or Rexx, and operating system shell scripts on systems such as UNIX.

In early 1996 Microsoft had a first stab at improving the situation by including the Internet Server Application Programming Interface (ISAPI) technology as part of Internet Information Server. ISAPI is an extension to the Windows Win32 API. It was developed as a way to create Web server software that interacts with the inner workings of Internet Information Server, bringing what was claimed to be a five-fold increase in performance. As you can well imagine from this description, as well as the immediate performance increase, it also had a side effect of increasing the complexity of the development for the programmer. It wasn't for the faint hearted, and it takes some serious hardcore programming knowledge to do ISAPI applications right.As well as ISAPI, Microsoft encouraged developers to embrace their Internet Database Connector (IDC) technology.This was a new way to connect Web sites to back-end databases through Open Database Connectivity (ODBC).

The ISAPI and IDC technologies lifted Microsoft's youthful and as yet unproven Web server from being a glorified file server to being a basic interactive application server platform for the first time.

Other vendors had tools out there, and several were very popular, such as Netscape Livewire. Livewire was a technology that ran under Netscape's Web server and used a version of JavaScript for page logic, and also used Java components. Unfortunately, Livewire had similar limitations to ISAPI in that it was a compiled technology and the server needed stopping and starting to make changes visible.

Why ASP Was Needed

Not all Web developers have the programming skills needed to write ISAPI applications, and because ISAPI requires the compilation of programs, there are extra steps in producing an ISAPI-based site that slow development down. Novice and intermediate programmers found the need to learn an industrialstrength language, such as C++, and compile even the simplest of their page logic into .dll files a real barrier.

Visual Basic programs, although easier to develop, when used for CGI, performed poorly and the overhead hogged resources. Other languages such as Perl require the Web server to launch a separate command-line program to interpret and execute the requested scripts, increasing page-load time and reducing server performance. CGI itself hogs resources because every page request forces the Web servers to launch and kill new processes and communicate across these processes. This is time consuming and also uses up precious RAM.

Another problem facing development teams in the mid 90s was the fact that a Web site is a mixture of Hypertext Markup Language (HTML) and logic.They needed a way to mix the programmer's code with the designer's page-layout HTML and designs without one messing up the other.There were many solutions to this problem, ranging from custom template systems to Sever Side Include (SSI) statements that told the server to execute code based on special HTML comment tags.

Database-driven interactivity was another challenge.The demand for complex Web sites had just kicked off, and developers needed to supply that demand in a manageable fashion, but the tools available did not make this an easy task.Those who could achieve it demanded rewards that matched the difficulty of what they were being asked to do.

What was needed was a solution for the rest of us. It needed to be a simple scripted text-based technology like Perl, so developers could tweak and alter their pages without compilation and with simple text-editing tools such as Notepad. It needed to have low resource requirements while keeping high performance; therefore it needed to be executed within the server environment just like ISAPI, but without the complexity. Designers and cross-discipline teams demanded that it should include SSI and template features to make integrating page layouts simpler to manage.To be truly popular, it should run off a language that would be easy to pick up and was familiar to a large community of developers. Enter Active Server Pages!

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