SAP Library - Find your answers

SAP Business One is a software that was bought over by SAP and it has been greatly enhanced over time, however, not much has been done to its architecture. SAP R/3 is indigenous to SAP and it has also undergone various re-engineering over time, especially as it relates to its architecture. A fantastic testimony to this position is in the architecture of its successor, SAP ECC.

Both SAP Business One and SAP R/3 are built on the concept of client/server architecture. So how do they differ? Let's first understand the relationship in a client server setup. A client server is a computer system design standard in which the client machines requests and gets back information from a distribution machine called the server.

SAP Business One as said earlier is based on client/server architecture, howbeit a "2 tier": strictly, clients and server. This technology is often referred to as a fat client. This is because all processing and business logic are carried out on the client. The result therefore is a system where logon and load balancing is a mirage.SAP Business One is a client-server application that utilizes the fat client technology.

A fat client is a typical two-tier, client-server system in which the application code sits on the client. The implication therefore is that virtually all processing is done on the client while the server merely serves as a data repository. This is in contrast to a "fat server" in which data handling and manipulation is carried out on the server.

In a fat client set up like SAP Business One, the client is explicitly installed on all client PC's separately from the server. This might be by remotely accessing the client system from the server or installing it independent of the server. A typical example of the former is a client installation done from the B1_XYZ folder (D:\Program Files\SAP\SAP Business One\B1_XYZ\Clients) in SAP Business One. The application code and the business logic typically sits on the client in a fat client architecture, hence the client does virtually everything. The performance of the client PC's are grossly independent of the performance of the server. The work method is to utilize the processing power available on the clients as opposed to the server. Despite these benefits and many more, this technology has its downsides.

Have you ever wondered why SAP Business One targets companies with 250 employees or there about? Aside the perception that the number (of users) is relatively typical of an SMB, the performance of systems in a fat client/thin server system diminishes when consistent client connection approaches 120 as a result of the server maintaining these connections as at when and when not needed. Also, more worrisome is the mutual alliance of the internet and fat clients. Third party systems like citrix server are used in SAP Business One to cushion this challenge. The benefits of load balancing cannot be optimized in a fat client set up. This is because individual client's idle time cannot be redistributed.

SAP R/3 is based on a three tier client/server technology. Typically, it is made up of three functionally distinct layers namely: the user interface, business logic and database.
The user interface, which is otherwise known as the presentation server displays the interface for users' communication with the SAP system. It is often referred to as the SAP GUI. As a matter of fact, it is a program called sapgui.exe. The application server is where the business logic and data manipulation takes place. Data processing, SAP administration tasks and client request/feedback management are handled within the business layer. The database layer is synonymous to the database server and it typically acts as a data repository for tables and other database objects and structures.

Ideally, an R/3 system is composed of one database server, one or more application servers and one or more presentation servers. SAP Business One on the other hand is composed of a database server and one or more presentation servers.
Source Kehinde Eseyin