Ivar Jacobson

Ivar Hjalmar Jacobson (born in Ystad, Sweden, on September 2, 1939) is a Swedish computer scientist.

He got his Master of Electrical Engineering at Chalmers Institute of Technology in Göteborg in 1962 and a Ph.D. at the Royal Institute of Technology in Stockholm in 1985 on a thesis on Language Constructs for Large Real Time Systems.

In 1967 he proposed the use of software components in the development of the new generation of software controlled telephone switches Ericsson was developing, in doing this he invented sequence diagrams and he developed collaboration diagrams. He also applied state transition diagrams to describe the message flow between the components.

He thought that there needed to be blue prints for software delevelopment, to do this he was one of the original developers of SDL (Specification Description Language), in 1967 SDL became a standard in the telecoms industry.

At Ericsson he also invented use cases as a way to write down software requirements.

In April 1987 he quit Ericsson and started Objectory AB where he developed the software process OOSE about 1992.

In October 1995 he merged Objectory with Rational Software and started working with Grady Booch and James Rumbaugh to develop first UML and later Rational Unified Process. Rational was bought by IBM in 2003 and Ivar decided to quit, but he stayed on until May 2004 as a executive technical consultant.