Relational Database - IBM System R
1 - About
IBM System R is a database system built as a research project at IBM San Jose Research (now IBM Almaden Research Center) in the 1970s.
System R was a seminal project: it was a precursor of (SQL), which has since become the standard relational data query language. It was also the first system to demonstrate that a relational database management system could provide good transaction processing performance.
System R's first customer was Pratt & Whitney in 1977.