IDS/II, introduced in 1975, was a chargeable program product. At this time the original version was labeled IDS/I.
It was not easy to use or implement applications with IDS, because it was designed to maximize performance using the hardware available at that time. However, that weakness was equally its strength because skilful implementations of IDS-type databases, such as British Telecom's huge CSS project (an IDMS database servicing more than 10 billion transactions per year), show levels of performance on terabyte-sized databases that are unmatchable by all relational database implementations. Charles Bachman's innovative design work continues to find state-of-the-art application with major commercial operations.