Shuchi: Good Morning! What good fortune it is to discover you here, especially since I have just been going through your slides of System Architecture. An admirable work, to be sure, but full of questionable thinking. Would you be good enough to discuss it with me?
Silky: Gladly. I do not leave Delhi until tomorrow and can think of no better use of my time than to explain you this.
Shuchi: Splendid! What puzzles me is mainly is why an organisation found it necessary to spend so much of their time on system architecture.
Silky: I'm glad you got right to the point because it shows how little you understand of what I was doing. Anyways, if we were planning to build a home, we would first lay out the floor plans, grouping each room by function and placing structural items within each room according to their best utility. This is not an arbitrary process – it is architecture. Moving from home design to IT system design does not change the process. Grouping data and processes into information systems creates the rooms of the system architecture. The architectural framework reduces information system complexity by identifying and eliminating redundancy in data. The resulting enterprise information architecture will have significantly fewer applications and databases as well as a resulting reduction in intersystem links. This simplification also leads to significantly reduced costs.
Shuchi: How is it done?
Silky: That implementation is what we call as application architecture.
In Single tier architecture: you need to separate your data from application even if they are on the same hardware, as in same laptop or desktop or server.
In two tier architecture: in case it’s on LAN i.e. local area network, applications are stored on individual machines or say computer and data is in server which can be accessed by using TCP or IP protocols.
Other than LAN, one can also use internet.
In three tier architecture: application is partitioned between business logic i.e. applications which are business critical are kept centrally and presentation logic i.e. applications which can be shared and are not business critical are kept locally.
In multi tier architecture: everything remains as it is; only the application is accessed via internet. Each application unit will have a web browser to access the information residing on the server side.
Shuchi: What if you have multiple applications?
Silky: In that case management becomes very complex. You get back to two tier architecture where you have different applications in different machines and data for each application lies in the server.
Either you can have Relational Database Management System (RDBMS), where application remains in your system and you have a corporate database i.e. integrated database which restores and maintains a backup and is easy to manage.
Or else one can go for ERP where you can integrate all the modules and processes of an organisation into a unified system. Your data will reside on RDBMS; only ERP system gets involved where there are different modules like HR, Finance, and Sales which can be access by using GUI in order to make any change in a particular module.
I think this discussion will help your basic understanding of the subject but for detailed discussion we need to sit some other day when we both are free and have no other works to concentrate in.
Suchi: Thanks for explaining the concept.
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