A newly joined project engineer goes to a “System Architecture Consultancy” for buying architecture blue print for his new software project, and this project engineer does not have any idea about the system architecture.

System Architect: Good morning, how may I help you?

Project Engineer: Very good morning.. I am here to buy an architecture blue print for my software.

System Architect: J.. You are at the right place.

                                We sell conceptual models that define the structure, behavior, and more views of   a     system.

Project Engineer: Before  buying a model from you, I would like to learn  about  system architecture. Can you help me on that?

System Architect : Sure … why not … but you will be charged for it J..

Project Engineer : Sure , no problem.

System Architect : Just Kidding....Lets me give you a brief idea about System Architecture .

A system architecture or systems architecture is the conceptual model that defines the structure, behavior, and more views of a system.

In software engineering, multi-tier architecture (often referred to as n-tier architecture) is a client–server architecture in which the presentation, the application processing, and the data management are logically separate processes. For example, an application that uses middleware to service data requests between a user and a database employs multi-tier architecture. The most widespread use of multi-tier architecture is the three-tier architecture.

Three-tier architecture

                    

   Three-tier is a client–server architecture in which the user interface, functional process logic ("business rules"), computer data storage and data access are developed and maintained as independent modules, most often on separate platforms.

Apart from the usual advantages of modular software with well-defined interfaces, the three-tier architecture is intended to allow any of the three tiers to be upgraded or replaced independently in response to changes in requirements or technology.

Three-tier architecture has the following three tiers:

Presentation tier

This is the topmost level of the application. The presentation tier displays information related to such services as browsing merchandise, purchasing, and shopping cart contents. It communicates with other tiers by outputting results to the browser/client tier and all other tiers in the network.

Application tier (business logic, logic tier, data access tier, or middle tier)

The logic tier is pulled out from the presentation tier and, as its own layer, it controls an application’s functionality by performing detailed processing.

Data tier

This tier consists of database servers. Here information is stored and retrieved. This tier keeps data neutral and independent from application servers or business logic. Giving data on its own tier also improves scalability and performance.

             I will end it here for today; tomorrow we will have a discussion about your software project for requirement gathering.

Project Engineer:   Sure, Thanks a lot for the info session.

System Architect: Your are Welcome... See you tomorrow.. bye.