Oslo Analyzer (1938 – 1954) was a differential analyzer type of computer, built in Norway from 1938 to 1942. It was the largest computer of its kind.
The differential analyzer was based on the same principles as the pioneer machine developed by Vannevar Bush at MIT. It was installed in the first floor of the Institute for Theorethical Astrophysics at the University of Oslo, under leadership of Svein Rosseland who had visited MIT in 1933. The machine had twelve integrators (compared to six of the original MIT machine) and could calculate differential equations of the twelfth order, or two simultaneous equations of the sixth order. When it was finished, the Oslo Analyzer was the most powerful of its kind.
Upon the German occupation of Norway on April 9, 1940, Rosseland realized that the machine might become a desirable research tool in the German war effort. So Rosseland personally removed all precision fabricated integration wheels and buried the wheels in sealed packages in the garden behind the institute.
The machine contributed to a number of scientific projects, both domestic and international. When it was dismantled, sections of it was placed at the Norwegian Museum of Science and Technology.