What is the following passage about?
IBM started working on a prototype system loosely based on Codd's concepts as System R in the early 1970s. The first version was ready in 1974/5, and work then started on multi-table systems in which the data could be split so that all of the data for a record (some of which is optional) did not have to be stored in a single large "chunk". Subsequent multi-user versions were tested by customers in 1978 and 1979, by which time a standardized query language – SQL[citation needed] – had been added. Codd's ideas were establishing themselves as both workable and superior to CODASYL, pushing IBM to develop a true production version of System R, known as SQL/DS, and, later, Database 2 (DB2).
Database
In the given passage, we come across words such as "Codd", "System R" and 
"SQL". These are all related to databases. Codd is a database expert who proposed various concepts for relational databases in 1969. He also came up with SQL (Structured Query Language), which allows us to interact with the data of a database using queries written in English-like language. System R was an experimental project by IBM that led to production versions like SQL/DS and DB2 later on. All these information make it clear that this article has something do with Databases.