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[[International Business Machines|IBM]] also had their own DBMS system in 1968, known as ''IMS''. [[Information Management System|IMS]] was a development of software written for the [[Apollo program]] on the [[System/360]]. IMS was generally similar in concept to Codasyl, but used a strict hierarchy for its model of data navigation instead of Codasyl's network model. Both concepts later became known as [[navigational database]]s due to the way data was accessed, and Bachman's 1973 [[Turing Award]] presentation was ''The Programmer as Navigator''. IMS is classified as a [[hierarchical database]]. [[IDMS]] and [[Cincom Systems]]' [[Cincom Systems#1970s|TOTAL]] database are classified as [[network model|network databases]].
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[[Edgar Codd]] worked at [[International Business Machines|IBM]] in [[San Jose, California]], in one of their offshoot offices that was primarily involved in the development of [[hard disk]] systems. He was unhappy with the navigational model of the Codasyl approach, notably the lack of a "search" facility. In 1970, he wrote a number of papers that outlined a new approach to database construction that eventually culminated in the groundbreaking ''A Relational Model of Data for Large Shared Data Banks''.<ref>Codd, E.F. (1970).[http://www.seas.upenn.edu/~zives/03f/cis550/codd.pdf "A Relational Model of Data for Large Shared Data Banks"]. In: ''Communications of the ACM'' 13 (6): 377–387.</ref>
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