The sector infrastructure is the basis for high-performance computing in the CSD with the respective computer centers at Forschungszentrum Jülich (JSC) and RWTH Aachen (IT Center). The effective use of ever more complex high-end systems demands a close cooperation between those responsible for infrastructure and its users. New hard- and software components are being developed, tested at an early stage, and investigated in co-design projects together with hardware experts and users. The SimLabs, Cross-Sectional Groups (CSGs), DataLabs, and TechLabs are located in the sector infrastructure and constitute the structural instruments of this cooperation.