Welcome to SAP BASIS Tutorials. The objective of these tutorials is to provide in depth understand of SAP BASIS. In these tutorials we will cover topics  Database, Operating system, communication protocols and other SAP modules like FI, HCM, SD etc. .

In addition to free SAP BASIS Tutorials, we will cover common interview questions, issues and how to’s of SAP BASIS.


SAP Basis is the technical core of the SAP (Systems, Applications and Products) software system. It defines the internal structure the SAP software and consists of the various system and user level components that help in configuration, installation, troubleshooting, updating or monitoring the applications. To get a better understanding of SAP features and technical aspects, take our online Introductory Course on SAP Basis.

SAP applications such as FI,CO,PP etc. can run and communicate with each other across different Operating systems and Databases with the help of BASIS.

Basis is known as Netweaver.

Alias of BASIS is SAP Application Server Technology and alias of netweaver is SAP Web Application Server.

After adding java stack (the applications which are developed in J2EE,BSP,JSP,etc..),enhanced security standard for business process.Both ABAP and Java stack can be monitored from one platform. Netweaver supports standard protocols such as HTTP,SMTP,XML,SOAP,SSO,WEBDAV,WSDL,WMLSSO,SSL,X.509 and Unicode format(representation of handling text).

We can say Basis is the operating system for SAP applications and ABAP.Basis provides services like communication with the operating system,database communication,memory management,runtime collection of application data,web requests,exchanging business data etc.

Basis supports a number of known operating systems (Unix flavors,Microsoft windows server edition,AS400,z/OS,etc) and databases (Oracle, DB2, Informix, Maxdb, Microsoft SQL Server,etc).

BASIS  tool has the following different functionalities:-

-System monitoring and administration tools

-Common monitoring tool CCMS(Computing Centre Management System) to monitor alerts of R/3 system from an one place.

-Server side scripting in ABAP and Javascript.

-Use of Business server pages to build online stores and portals.

-Database monitoring and administration utilities

-Resource management like memory,buffer,etc.

-Authorization and profile management tools for user management.

-Internet access control to the system and business objects.

-Transfer modifications in screen,program,layout from the development to production system for accuracy purpose by Transport Management System.

-Client server architecture and configuration.

-Graphical User Interface designing for the presentation layer.

SAP R/3 Architecture


It is the interface to a user. This is the only layer from where users connect to the SAP system. DIAG (Dynamic Information Action Gateway) is the protocol which is used to communicate b/w user and SAP system. Using this we can have, Our own font settings, Our own languages settings. It is user friendly. With the help of message server which identifies favorite server and logs onto it. It is intelligent server. It is operating system & db independent.

Presentation layer is nothing but SAP GUI: SAP GUI is to facilitate users to log into R/3 system. This logon can be used to all the components of SAP (CRM, APO, BW, XI etc.)

Types of SAP GUI:

SAP GUI for Windows.



SAP GUI for Windows: It is for the windows environment. Support platforms Includes windows 98, windws NT4, Windows 2000 and Windows XP.

SAP GUI for HTML: Front end requires only a web browser, an ITS is necessary to convert the presentation into HTML.

SAP GUI for JAVA: It is used only where java is supporting. It supports Windows 98, windws NT4, Windows 2000 and Windows XP,MacOS 9,MacOS x Linux, HP UX, Solaris, AIXOS/2.

Application layer/tier/server:

It is used to Provides business areas and Configure work process and Reduce traffic on DB. It is used Configure memory areas. and Business logic & presentation logic handled.

It consists of dispatcher, work processes, memory areas, buffer areas and interpreters,

Dispatcher: There will be only one dispatcher per instance. This is used to handle the user requests. Dispatcher receives the users request and keeps them in the queue (dispatcher queue) based on the available free resources, user request will be assigned with work process on FIFO basis. Dispatcher runs by an executable disp+work.exe. This can be monitor by using a command line tool DPMON (It listens on the port 32<sysnr>).

Dispatcher assigns the user request to a dialog work process, so it will distribute request to respected work process.

Dialog process: It is used for handling generation of reports, updating the temporary tables, updating the spool tables, updating the background tables so that update, spool background processes reads those tables for execution. If the request is long running job then it will assigns to its relevant work process.

Dialog work process run time is restricted to 600 sec to 1800 sec based on the

parameter( rdisp/max_wprun_time).

Update work process: This process is used to update the database initially update requests are handled by dialog work process as they couldn't  execute within the specified time, it is called asynchronous update process. If the task has been moved to update work process then first dialog process updates the temporary tables (VBHDR, VBDATA, VBERR, VBMOD) update process reads the temporary tables and update the database.

Enque process: Enqueue process is used to lock and unlock SAP objects. It will update the database and takes the users request. In order to handle this mechanism SAP has defined enqueue and dequeue (unlock) modules. Enqueue process will issue locks tomessage server to all the dialog instances. That is dialog communicates with message server & message server in term talks to enqueue to get the lock. Dialog process communicates with the message server and message server communicates to enqueue. Dialog processes on central instance can communicate with enqueue directly to obtain locks.

Background Process: The long running, time consuming and expensive reports or updates will be used to schedule in the non-dialog mode using the background process. Dialog work process receives the background request & updates background request & updates background job tables. Background work process reads the job tables for every 60 sec & executes them

Message Server: Message server is used to communicate with all the available dispatchers under the port number 3600+sys no. If logon load balance is configured, message server identifies the least loaded server in the logon group. It is run by an executable msg_server.exe. This is also used to communicate with enqueue to issue locks to the work process coming from dialog instance.

Gateway: There will be one gateway work process for each instance. Gateway is used to communicate with external system. It listens on the port 3300+sys no

Spool Process: Spool process is used to output the documents to the printer, fax, email, pager and sms. Dialog process receives the spool request and updates spool tables or stores spool data at OS level. Spool process reads the spool tables or spool data and output to specific device.

Note: All the work process runs with executable disp+work.exe

Memory Areas: In order to define a work process we should have enough resources at the rate of 75mb to 150mb for each work process. When the user request is assigned to a work process, work process requires certain amount of memory to execute the user request.

Eg: Roll memory, extended memory and heap memory

Buffer Areas:

There are two types of buffer areas

 - User related buffer (user specific)

-  R/3 buffer (non-user specific)

User buffers are nothing but user context.

User Context: User context is the area where user logon attributes, parameters, authorizations and earlier accessed content are stored. These are valid until the user session. User logout, buffers are lost.

R/3 buffers: Frequently accessed contexts like programs, tables, fields, currencies, calendar, and measurements are stored in R/3 buffers.

The data which is frequently accessed and rarely changed is eligible for buffering. These buffers are accessed by all the users. These will remain until the restart of the instance. If the instance is restarted, buffers are lost.


1. ABAP Interpreter: This is used to interpret the ABAP code embedded in the user request

2. Screen Interpreter: This is used to interpret the screens.

3. SQL Interpreter: This is used to interpret SQL Statements in the ABAP program.

Note: Task handler which is a part of work process handles the interpreters.

Dispatcher: It receives user request and assigns work process or keep user request in dispatcher queue.

Task Handler: It is the agent which processes the user request by segregating into screen, ABAP, SQL interpreters.

User Context: The user context is the buffer area where it stores user logon attributes, authorization parameters.

Dispatcher Queue: It is the queue where user exists when work processor is busy. It follows FIFO.

Database Layer/tier:

It is the layer where database is hosted. It has its own memory areas, buffer areas, work processes etc. A central RDBMS realizes the database layer of SAP R/3 systems. Initially SAP database will use open SQL but database client will convert open SQL into native SQL. That is the reason SAP supports different databases.

These core tutorials will help you to learn the fundamentals of SAP Basis.

For an in-depth understanding and practical experience, explore Online SAP Basis Training.

Features of SAP Basis

SAP Basis supports the SAP modules and applications on all the technical aspects of its smooth functioning. Consisting of low level services like database communication and high-end tools for system administrators and users, SAP Basis is the platform on which the various solutions run. It has several features such as:

-Database administration – It focuses on the administrative functioning of the various applications by monitoring the database that the SAP system uses.

-System administration – It acts like an interface between the system components and the Basis components, emphasizing on the development platform and data dictionary

-User Administration – It provides the various tools required to help the users manage activities like trouble-shooting, up gradation, configuration, installation etc.

-Security Administration – Maintains the security of the SAP systems by integrating the authorization module that protects the system from potential breaches, data corruption etc.

-Client-Server Architecture – It normally uses the real-time 3-layer architecture consisting of the Presentation layer, Application layer and Database layer, thereby following the SAP R/3 architecture. These various layers in turn have specific features that allow for the functioning of the SAP applications.

-SAP GUI – SAP Basis defines the graphical user interface (GUI) components of the system. There are three types of interfaces that are widely used – GUI for Windows, GUI for Java and GUI for HTML. It provides the required platform for the implementation of these user interfaces.

Advantages of SAP BASIS

SAP  is OS Independent (Windows, AIX, Linux (Cent0S, fedora, RHL, SUSE, ORACLE)

SAP is DB Independent (Oracle, DB2, MSSQL, SAPDB, Informicx, Obsolete).

Rich set of modules (SD-Sales and Distribution, MM-Material Management, PP-Production Planning, FI- Financial accounting, CO- Controlling, HR, QM- Quality Management, PM- Plant Maintenance).

Rich set of Industry solutions.

User friendly GUI.

Provides support for all the languages. [Multi coded Page].

Optimize resources in an Organization enterprise.

Rich security features to control the data upto field level, Activity level, org level.

SAP provides 24x7x365 support for production system.

Rich set of components (SAP BW, CRM, SRM, SCM).

Web based.

Mobile infrastructure is built in to support handheld devices.

built on robust platform "Netweaver".

Interface support for printers, scanners, etc.

High level of stability and performance, response times are consistently under one second.

Significant cost and time saving.

Predefined Business packages, best practices, business scenarios, building blocks, with predefined implementation road map to reduces TCO (Total cost of ownership) for implementation.

SAP can be easily adaptable to suit the requirements of the customer.

SAP provides user friendly graphical user interface (Windows, JAVA).

Provides solution manager to monitor, administer the customer systems and raise the alerts and provides early watch alerts through emails and SMS etc.

It communicates with non-SAP products ( Oracle, Peoplesoft, Flat Files, excel file) etc. there are various predefined interfaces that are inbuilt in SAP to communicate with external or non SAP Systems.

Enterprise with it supports multi tier architecture ( GUI, Web, Mobiles, ...etc.) ..etc.

SAP Provides market place on the web for the following.

-Knowledge base.

-Download software.

-Installation guides.

-Patches related to program.

-License keys for installation and upgrades.

-Developer users and generate access keys.

-Create and maintain Remote connections so, that SAP can support customer systems remotely.