The DPAC data processing flow as used for Gaia DR1 in schematic and simplified form. Thick lined boxes show processing steps, rounded boxes represent calibrations derived during the processing, while thin-lined boxes show processing outputs. The solid lines indicate the processing flow as realised for Gaia DR1, while the dashed lines indicate processing flows that were not implemented for Gaia DR1. The remarks in italics highlight important shortcomings in the Gaia DR1 processing.