ABSTRACT

In the late 1960s, the first generalized database management systems (DBMSs) started to emerge (IBM’s IMS, Cullinane’s IDMS, Software AG’s Adabase, etc.). These systems replaced old-fashioned indexed-sequential files (ISAM), a data organization method with fixed length records, limited indexing capabilities, and limited possibility of inserting records without performance deterioration. Vendors lacking a DBMS felt that they were at a competitive disadvantage. What did the hapless “have-nots” do? They tinkered slightly with their products and rechristened them as DBMS.