SAP Business Warehouse (abridge SAP BW) is SAP’s Enterprise Data Warehouse product. It can transform and consolidate business information from virtually any source system. It ran on industry standard RDBMS until version 7.3 at which point it began to transition onto SAP's HANA in-memory DBMS, particularly with the release of version 7.4.
In 1998 SAP released the first version SAP BW providing a model-driven approach to EDW which made data warehousing easier and more efficient, particularly for SAP R/3 data. Since then SAP BW has evolved to become a key component for tens of thousands of companies. The following article provides the history of SAP BW from inception to the newer releases powered by SAP HANA.
1. http://www.sap.com/pc/tech/data-warehousing.html