How to grasp High Level & Fundamental understandings of SAP System Architecture?

It is an undeniable fact that SAP gains more andforecasting.  Forecasting is one of core sub-modules,
more customers such as big US and globaland Planning is based on sophisticated planned data
Corporations and government. which is forecast data.  The name SCM (Supply
SAP's greatest opportunity probably lies beyondChain Management) is also used interchangeably to
Microsoft or IBM or Oracle.  SAP AG is a globalrefer APO component.  However, please remember
software company headquartered in Walldorf,that SCM itself is a generic term and discipline that is
Germany.  SAP simply stands for Systemstaught at major university or institution.  DP
Applications and Products in Data Processing.   It will(Demand Planning, i.e. Forecasting) and SNP (Supply
be highly worthwhile to go over the essentialNetwork Planning) are major sub-modules of APO
components of SAP System as more and moreSCM.  It is interesting to note that as the SAP gains
companies are moving toward using ERP packagemore popularity among companies, SAP is currently
such as SAP rather than relying on traditional in-houseadding Industry-unique modules called SPP (Service
development of Corporate Application Systems.Part Planning) with cooperation of major US Auto
First, there is R/3 or ERD or ECC.  The name of thisIndustry (Ford) and CAT-Logistics. 
component has been evolved, but the essentialThird piece is CRM (Customer Relation
function of system component has not changedManagement).  This component is most likely
much.  ERP stands for Enterprise Resource Planningcorresponding to Traditional Customer Order
Software product SAP AG.Processing System.  Customers can place orders,
This component has its own several sub-modulesand orders are processed by CRM.  Customer data
such as MM (Material Management), SD (Salesand Order data and material data are keys to
Distributions), FI/CO (Financial and Costing and Billing),manage this component.   
PM (Plant Maintenance/Production Planning), WMThere are also many layers/tools that are interfaced
(Warehouse Management) and HR (Human Resourcewith above three components.  For instance, ICH
Management).   It has Workbench environment(Inventory Collaboration Hub), EWM (Extended
where staff can develop customized program usingWarehouse Management under SCM), XI (Exchange
ABAP programming and database tables to supportInfrastructure), BI (Business Intelligence) and EP
companies' own internal business processing.  Each(Enterprise Portal) could be those.  SAP connects
sub modules support many screens/transactions andabove three components using CIF (Core InterFace
reporting transactions to easily keep track ofbetween ECC and SCM) and CRM Middleware
inventory, orders, movement of goods.  Either(between ECC and CRM) to enhance data integrity
Business customers or traditional IT staff canand connectivity. 
relatively merge together to design and developAuthor attended several SAP classes in MM, SCM and
various business processes.  ECC (Enterprise CentralCustomizations provided by SAP AG.  There are still
Component)  is recent name for R/3 or ERD.  Evenstrong demands for SAP system and classes, and it
huge company can be sufficiently supported by thisis hoped that more affordable training classes and
one component. materials will be available by other training agencies
Second component is called APO (Advanced Planningvery soon.  It is noted that there are
& Optimization).  This component is all aboutalso hands-on training site which provides CBT and
planning using demand data and the power ofself study.