  Systems Engineering (SE) is the set of processes and documentation required
for successfully realising large-scale engineering projects, but the classical
approach is not a good fit for software-intensive projects, especially when the
needs of the different stakeholders are not fully known from the beginning, and
requirement priorities might change. The SKA is the ultimate software-enabled
telescope, with enormous amounts of computing hardware and software required to
perform its data reduction. We give an overview of the system and software
engineering processes in the SKA1 development, and the tension between
classical and agile SE.
