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03 November 2012



While dealing with the Smartplant Tools, one must have come across the term 2-Tier tool and 3-Tier tool. I'm focusing about the architecture of 2-3 Tier Software Applications. Initially, when the problem came across to work upon data by multiple users, peer to peer computing came into picture. This scenario was great to use as each connected computer acted like server as well as client. But the problem was that the connections were made in sessions. The software was installed in a network computer and was used by multiple computers. The problem was with the security of the network as it was very difficult to monitor or supervise the network activities.

Client-Server (2-Tier) architecture overcomes the limitations of Peer-to-Peer computing. A central system is set up as server. This server can have more than one connection at a time (although the number of connections can be restricted depending upon the capacity of servers). In such architecture, a computer (user may be an appropriate word) which is client requests a service to the service provider which is server. The server processes the request and reverts the result to the client. A client does not share its resources, but request's the server content or service function. In short, client initiates communication session with server which awaits incoming requests.

Although, the Client-Server model looks perfect when seen upon, yet it has a major disadvantage. The client performs its operation directly on server. Although this problem is irrelevant to Smartplant tools. The tool like SPPID and SPF has to perform that way. But the tool like SP3D works on a different model. It is known as 3-tier architecture. This architecture is an extension of Client-Server Model. It has three layers namely Presentation, Processing and Data Management.

Presentation Tier
The task of this layer is to request and receive. It sends a request to the Logic Tier and receives the result from it.

Logic Tier
This layer coordinates the application, processes commands, makes logical decisions and evaluations, and perform calculation. It exchanges the dialog between Presentation Tier and Data Tier after valid operations.

Data Tier
The data is stored over here. On request, it passes the result to Logic Tier, which in turn sends it to the Presentation Layer.

There are tools other than Smartplant that work on more than these tiers, but it is not needed to discuss them over here. Although, FYI, 3-tier or more than 3-tier are simply referred as n-Tier architecture.

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