The Square Kilometre Array Science Data Processor. Preliminary compute platform design

The Square Kilometre Array is a next-generation radio-telescope, to be built in South Africa and Western Australia. It is currently in its detailed design phase, with procurement and construction scheduled to start in 2017. The SKA Science Data Processor is the high-performance computing element of the instrument, responsible for producing science-ready data. This is a major IT project, with the Science Data Processor expected to challenge the computing state-of-the art even in 2020. In this paper we introduce the preliminary Science Data Processor design and the principles that guide the design process, as well as the constraints to the design. We introduce a highly scalable and flexible system architecture capable of handling the SDP workload.