What it is
High-Performance Computing (HPC) means using supercomputers — vast clusters of tightly connected machines working in parallel — to solve problems far beyond the reach of an ordinary computer: climate modelling, drug and materials discovery, engineering simulation and training large AI models. The EuroHPC Joint Undertaking (EuroHPC JU) is the EU body that makes this happen at European scale. It is a legal and funding partnership between the EU, participating countries and private partners, created in 2018 and reinforced in 2021, that co-invests in building and operating supercomputers and in the research, applications and skills around them.
The point is pooling. Rather than each country trying — and mostly failing — to fund a top-tier machine alone, EuroHPC combines EU budget with national contributions to procure shared systems hosted in different member states but available to users across Europe. The result is a fleet of some of the world's most powerful computers operating under EU governance.
How it works in practice
Three things make HPC, and EuroHPC, work.
1. Massive parallelism. A supercomputer is built from thousands of nodes (each a server with many CPU cores, often paired with GPU accelerators). A problem is split into pieces that run simultaneously across them. Performance is measured in FLOPS (floating-point operations per second): petascale systems do 10¹⁵ FLOPS, and exascale systems reach 10¹⁸ — a billion billion calculations per second.
2. Fast interconnect. Parallelism only pays off if the nodes can exchange data quickly, so HPC clusters use very low-latency, high-bandwidth networks (such as InfiniBand) and a communication standard, MPI (Message Passing Interface), that lets processes coordinate across nodes. The interconnect is as defining as the processors.
3. Shared, scheduled access. Many users compete for one machine, so jobs are submitted to a batch scheduler that queues and allocates resources. Software environments must be portable and reproducible, which is why containerisation increasingly appears in HPC workflows.
EuroHPC has used this model to deploy a recognisable fleet: LUMI in Finland, Leonardo in Italy and MareNostrum 5 in Spain are among Europe's pre-exascale flagships, and JUPITER in Germany is Europe's first exascale system. These machines are heavily used for climate science, AI and industrial research.
| Term | Meaning |
|---|---|
| Node | One server in the cluster (CPUs, memory, often GPUs) |
| FLOPS | Floating-point operations per second — the speed measure |
| Petascale / Exascale | 10¹⁵ / 10¹⁸ FLOPS performance tiers |
| MPI | Message Passing Interface — how parallel processes communicate |
| Interconnect | Low-latency network linking the nodes (e.g. InfiniBand) |
| EuroHPC JU | The EU Joint Undertaking that funds and governs the machines |
The EU dimension is the whole rationale. EuroHPC is explicitly about digital sovereignty — ensuring Europe owns and controls world-class compute rather than depending on others — and it connects to adjacent EU initiatives: the European Quantum Communication Infrastructure (EuroQCI) and the push to develop European processor technology. Access is allocated to researchers, public bodies and industry (including SMEs) across the Union, making top-tier computing a shared European capability rather than a national luxury.
Common points of confusion
- A supercomputer is not one giant computer. It is a tightly coupled cluster of thousands of nodes working in parallel — its power comes from coordination at scale, not from a single huge processor.
- EuroHPC is a governance and funding body, not a single data centre. The Joint Undertaking co-funds and oversees machines hosted in several member states; the supercomputers (LUMI, Leonardo, JUPITER) are the assets, EuroHPC JU is the organisation.
- Exascale is a performance tier, not a brand. "Exascale" means crossing 10¹⁸ FLOPS; JUPITER is an exascale machine, but the word describes the capability, not a specific product.
Why it matters for EU infrastructure specialists
HPC is where infrastructure meets EU strategy, and EuroHPC is the flagship example a competition is likely to reach for. For EPSO/AD/429/26 Field 1 (ICT Infrastructure), expect questions on what the EuroHPC Joint Undertaking is and why it exists (pooling, sovereignty), on naming or recognising its supercomputers, or on core HPC concepts such as parallelism, FLOPS, exascale and MPI. Knowing both the technology and the EU policy context is exactly the blend the exam tests. Build that fluency with the full study pack: Prep for AD7 ICT Infrastructure on Prep4EU