Design-led Software Strategy for the 2df Survey Spectrograph

We describe the novel approach used for the software developed for the 2dF survey spectrograph. 2dF is a 400-ber multi-object spectrograph designed for the Anglo-Australian Telescope. One of its primary missions is a survey of 250,000 galaxy redshifts within two years, and on-line, real-time and nished product data reduction is the requirement driving the software design. To achieve these goals the software makes extensive use of prior knowledge of the optical design of the spectrograph to minimize the number of free parameters involved.