Specifications

Introduction 11
assigned a primary role by the dispatcher that will control, to a certain degree,
what type of work will be performed by that work process. The number of work
processes and the types that can exist for an instance are controlled by the
instance profile. The duration of a work process is the time between screen input
and screen output from the presentation server. The work process starts a
commit before the output is displayed to the screen. The R/3 system applications
and custom-written application enhancements developed using the ABAP/4
Workbench are processed in this layer.
Since Internet technology does not handle business transactions on its own, the
Internet enabling layer has been created above the application layer. The Internet
enabling layer extends the three-tier R/3 architecture into a multi-layer internet
architecture.
1.6.3 Presentation Layer
The presentation layer of R/3 is called SAPGUI . It is closest to the user and
provides a graphical user interface for the end user.
A
two-tier configuration is a hardware configuration in which a single machine
serves as the application server and the database server. It does not need to
interact with another machine to service the R/3 end-user requests.
In a
three-tier hardware configuration , an application server is not a stand-alone
server. It must work in conjunction with a database server in order to provide the
end user with services. There may be multiple application servers in a three-tier
configuration.
To summarize, in the R/3 system, the data manipulation (the database server) is
separated from the execution of programming logic (application servers), which in
turn is separated from the presentation of data and control of user interaction
(front end servers). The protocol between the application server and the
presentation server is minimized to keep the network traffic as low as possible.
1.7 SAP Releases
There have been the following SAP R/3 releases to date:
• 2.1
• 2.2
• 3.0 (3.0A,3.0B,3.0C,3.0D,3.OE,3.0F)
• 3.1 (3.1G,3.1H)
• 4.0 (4.0A)
Version 4.0A is the latest SAP R/3 version.
R/3 3.1 integrated numerous R/3 Internet applications. Also, R/3 3.1 offers more
than 150 new process-oriented business application programming interfaces
(BAPIs) for third-party vendors and developers.
Release 4.0 can manage the entire value chain from point-of-sale to
point-of-production. It has enhanced key logistics, human resources, and
financial functions that extend the enterprise. Release 4.0 contains a broad array