PRESENTED BY:
ABHINAV SAXENA

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ERP SAP
INTRODUCTION
After the Internet, sap r/3 is one of the hottest topics in the computer industry, and the company that developed it, SAP AG, has become one of the successful in the software market.
The SAP R/3 system is targeted to most industries: manufacturing, retail, oil and gas, electricity, healthcare, pharmaceutical, banking, insurance, telecommunications, transport, automotive, chemical, and so on.
All hardware vendors without exception are fully engaged to partner with SAP: currently AT&T, Bull, Compaq, Data General, Digital, Hewlett-Packard, IBM, Pyramid, Sequent, Siemens-Nixdorf and SUN has supported and certified SAP R/3 platforms.
SAP AG was found in 1972 by four former IBM employees. Since its foundation, SAP has made significant development and marketing efforts on standard application software, being a global market player with its R/2 system for mainframe applications and its R/3 system for open client/server technologies.
The company name SAP stands for Systems, Applications and Products in Data Processing. It is a standard software package that can be configured in multiple areas and adapted to specific needs of the company. To support those needs, SAP includes large number of business functions, leaving room for further
Enhancements or adaptability to business practice changes.
The lower layer is made of operating system, physical database (whose software is included in the SAP kit), and the network. The middleware layer, which is above it, interfaces with the lower one and integrates SAP applications on top of it. This middle layer is known as the basis system, or R/3 kernel, and includes components such as the ABAP/4 development work bench, the system administration tools, batch job handling, authorization and security management, and all cross application modules.

ABAP/4 is the 4GL (fourth-generation programming language) in which all R/3 applications (the upper layer) are developed.
Middleware are the layered software components that facilitate the development of client/server applications that can be deployed in heterogeneous vendor platforms.
The basis system, also known as kernel, is the SAP R/3 middleware. The upper layer, the functional layer, contains the different business applications: financial, human resources, sales and distribution, materials management, and so on.
The integration of all applications relies on the basis system.The R/3 kernel makes use of standard communications and application program interfaces to access the operating system, the database, and the network. This architecture allows users to change system configuration and install new systems without interrupting or altering the applications themselves.
In general client/server is a style of computing that distributes the workload of a computer application across several cooperating computer programs. This type of computing separates user-oriented, application, and data management tasks. Client/server is mainly a software concept that includes a set of service providers and service requesters. In client/server computing, individual software components act as service providers, service requesters, or both. These software services communicate with each other via predefined interfaces.
Major advantages of the client/server approach are as follows:
• Flexible configuration
With the deployment of standard communication interfaces, there are many possibilities for planning a client/server installation: from a centralized Configuration to a highly distributed system.
• Workload distribution
Since application servers work in parallel, and communicate with the data base, users can be evenly distributed based on their job tasks. Also there is the possibility of deploying dedicated application servers to specific business areas.
• High scalability
Client/server permits users to adapt their capacity of the hardware according to the performance
Needs of the businesses, such as adding application servers when there is an increase in the number of users, when additional modules start production, and when data base becomes larger. This enables companies to protect their hardware and software investments.
One of the widely used client/server configurations with the R/3 system is the three-tiered architecture, which separates system’s computers in to three functional groups: presentation, application, and database. The central server contains the database, widely known as database server
• Application servers
Include the processing logic of the system, including services such as spooling, dispatching user requests, and formatting data.
The tasks related to presentation of data are handled by the presentation servers, which typically are personal computers or, workstations, enabling easy access to the system.
Communication among the three tiers is accomplished with the use of standard protocol services, such as the one provided by TCP/IP or CPIC. The key to SAP/R3 success was the strategy of making open solutions, in which applications can run on multiple operating systems, databases, and communication technologies.
This enables customers to remain independent of a single vendor if they wish.