SAP BASIS Tutorial

 

 

It is the interface to a user. This is the only layer where users connect to the SAP system. DIAG (Dynamic Information Action Gateway) is the protocol that is used to communicate b/w user and SAP system. Using this we can have, Our own font settings, Our own language settings. It is user friendly. With the help of the message server which identifies favorite server and logs onto it. It is an intelligent server. It is an operating system & DB independent. The presentation layer is nothing but SAP GUI: SAP GUI is to facilitate users to log into the 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 HTML.

SAP GUI for JAVA. SAP GUI for Windows: It is for the Windows environment. Support platforms Include windows 98, windows NT4, Windows 2000, and Windows XP. SAP GUI for HTML: Front end requires only a web browser, and it is necessary to convert the presentation into HTML. SAP GUI for JAVA: It is used only where java is supporting. It supports Windows 98, Windows 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 the work process and Reduce traffic on DB. It is used to Configure memory areas. and Business logic & presentation logic handled. It consists of the dispatcher, work processes, memory areas, buffer areas, and interpreters,

 

Dispatcher: There will be only one dispatcher per instance. This is used to handle user requests. The dispatcher receives the user's request and keeps them in the queue (dispatcher queue) based on the available free resources, user requests will be assigned with the work process on a 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 requests to a respected work process.

 

Dialog process: It is used for handling the generation of reports, updating the temporary tables, updating the spool tables, updating the background tables so that update, spool background processes read those tables for execution. If the request is a long-running job then it will assign 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 the 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 the update the work process then the first dialog process updates the temporary tables (VBHDR, VBDATA, VBERR, VBMOD) update process reads the temporary tables, and updates the database.

Unique process: Enqueue process is used to lock and unlock SAP objects. It will update the database and takes the user's request. In order to handle this mechanism, SAP has defined enqueue and dequeue (unlock) modules. The Enqueue process will issue locks to the message server to all the dialog instances. That is dialog communicates with the message server & the message server in term talks to enqueue to get the lock. The dialog process communicates with the message server and the message server communicates to enqueue. Dialog processes on the 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. The dialog work process receives the background request & updates the 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, the 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 an external system. It listens on the port 3300+sys no

 

Spool Process: The 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 the OS level. The spool process reads the spool tables or spool data and output to a 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, the work process requires a 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 buffers are nothing but user context.

User Context: User context is the area where user login 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, calendars, 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.

Interpreters: 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 the 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 that processes the user request by segregating into the screen, ABAP, SQL interpreters.

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

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

Database Layer/tier:

It is the layer where the 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, the SAP database will use open SQL but the database client will convert open SQL into native SQL. That is the reason SAP supports different databases.

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 as 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 up to field level, Activity level, org level.
• SAP provides 24x7x365 support for the production system.
• Rich set of components (SAP BW, CRM, SRM, SCM).
• Web-based.
• Mobile infrastructure is built to support handheld devices.
• built on the 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 a predefined implementation road map to reduce TCO (Total cost of ownership) for implementation.
• SAP can be easily adaptable to suit the requirements of the customer.
• SAP provides a 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.

• -Knowledgebase.
• -Download software.
• -Installation guides.
• -Patches related to the 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.