Software Architectures - Essay Example

Logic tier is associated with the manipulation of the data in use by the application. It is commonly referred to as the implementation of "business logic", the "brains" of the application. Presentation tier is associated with the displaying of the manipulated data on the screen. (Scott Rosenthal, 2007) In the beginning, all three functional tiers were located at the central server, the Mainframe. Users could access this centralized computer by the means of dumb terminals. Applications in which the three tiers are located at the user's local system are known as Desktop applications.

The commonly used Microsoft Office application is an example of desktop application. The 1980s saw the advent of the popular two-tier, client-server architecture. In this arrangement the application running in the client machine interacts with the server, most commonly, a database management system. The client contains the presentation logic and the business rules. Thus making changes to the business rules caused changing and redistributing the application. This gave rise to the implementation of the three-tier architecture which visualized the separation of the presentation logic and the business rules.

(Scott Rosenthal, 2007) Adopting of any particular architecture for a software application is based on what that a. It depends on the number of users trying accessing the application. Two-tire client-server architectures work fine if the number of users is expected to be low, less than 100 and when non-real-time information processing is required. Today, however, the increasing complexity of client/server applications, the sophistication of technologies available and access to the internet all contribute to the high performance demand of the application.

The trend today, therefore, is evidently towards more complex three-tier architectures.ExamplesToday, the IS (information systems) organizations prefer to buy certain applications such as those for accounting and human resources instead of developing them themselves. The vendors of packaged enterprise software, such as SAP, Oracle etc. that make these applications have implemented them on three-tier client/server architectures because to them the sophistication of available technologies required a three-tier architecture to provide adequate performance.

(Gill, 1998)The advent of internet giving rise to millions of users requesting for information processing and companies adding back-end databases have given rise to the adoption of three-tier architecture or conversion from two-tier to three-tier architecture in application development in order to provide the increased scalability needed.Today, over the internet, real-time information processing is required everywhere. Be it sending/receiving important e-mails for business purposes, playing online games with people in different parts of the world or even browsing for information for school assignments.

This demand for real-time information processing has obligated the web application developers to