Reaching Exascale compute performance at an affordable budget requires increasingly heterogeneous HPC systems, which combine general purpose processing units (CPUs) with acceleration devices such as graphics processing units (GPUs) or many-core processors. The Modular Supercomputing Architecture (MSA) developed within the EU-funded DEEP project series breaks with traditional HPC system architectures by orchestrating these heterogeneous computing resources at system-level, organizing them in compute modules with different hardware and performance characteristics. Modules with disruptive technologies, such as quantum devices, can also be included in a modular supercomputer to satisfy the needs of specific user communities. The goal is to provide cost-effective computing at extreme performance scales fitting the needs of a wide range of Computational Sciences. This approach brings substantial benefits for heterogeneous applications and workflows since each part can be run on exactly matching computing resources, therefore improving the time to solution and energy use. It is therefore ideal for supercomputer centers running a heterogeneous mix of applications.

This work introduces the Modular Supercomputing Architecture - which constitutes the central element in Europe’s roadmap to Exascale computing -, including its history, its role in Europe’s Exascale computing strategy, its hardware and software elements, and experiences from mapping applications and workflows to MSA systems.