WHAT IS ABAP Language

                                    ABAP/4 LANGUAGE:

(Advance Business Application Programming)

ABAP is a business programming language.
ABAP is a high level programming language created by SAP. ABAP is considered one of many fourth generation languages and it was developed in early 1980s. ABAP is an acronym for 'Advanced Business Application Programming' (in German it means Allgemeiner Berichtsaufbereitungsprozessor).
ABAP is used by SAP to develop SAP R/3 applications. ABAP is very easy to learn. However to start programming with ABAP programmers are expected to have some basic knowledge of data bases, other programming knowledge and preferably also some basic principles of Object oriented concepts.
ABAP programs are stored in a database unlike with other popular programming languages like C++ or JAVA where the programs are stored as files on the computer. The ABAP environment (syntax checking, compiling and executing) is a part of SAP Basis component.
All SAP data and programs run on an SAP system. A SAP system consists of one or more application servers, data base and client terminals. A typical SAP landscape will have 3 systems for Development, Testing and  Production.

ABAP Kernel

All ABAP programs are executed using ABAP Kernel. To understand how ABAP programs are executed and communicate let us first try to understand about Kernels.
In modern computer science world, the kernel is defined as the central component of any operating system. It is responsible for managing the system's resources like CPU, memory, communication with I/O devices etc. A kernel is very basic component of the operating system. It provides the lowest level of abstraction layer for the resources. The below image explains the functionality of a kernel.

Functions of Kernel:

• Kernel is responsible for deciding at any point which program (many programs could run parallely) should be allocated to the processor (and which processor, if more than one are available).
• All programs use memory - to store data and process instructions. Often multiple programs will want access to memory. Th job of kernel is to decide which process should use memory and what to do if enough memory is not available.
• Almost all programs interact with input / output devices like monitor, key board, mouse etc. The kernel allocates these requests to appropriate devices or sub section of devices.

Now, one can imagine the job of an ABAP kernel. Often kernel programming is considered to be the most difficult part of any system design.


Under SAP R/3 while default you can find :

                

·                                            4^th generation language, using SQL, ABAP,…

·                                            17000 predefined database tables and

·                                            13000 predefined applications

BUSSINESS APPLICATION:

Example:

ü      Generating a bill

ü      Purchase order

ü      Invoice generating.

APPLICATIONS:

Ø      Collection Of Programs (Or) Single Program

§         It is divided into two parts: 1) development

         2) Customize( Tailoring)

APPLICATION
Development	Customize(tailoring)
Creating an application from the scratch
	Modifications	Enhancement
	Ex: changing the existing the standard application	Ex: adding new few features to existing applications