if you talk about hpc you can talk about high speed networks that connect supercomputers or about the design of the latter. you also can talk about politics and compare performances and political will and financial support. such a comparison report on hpc was published in september 1991 in the us upon a congressional request. the topic at that time: external networks.

The [US] President’s fiscal year 1992 budget request seeks $92 million for work related to developing NREN. In addition, the Corporation for National Research Initiatives, a nonprofit organization created in 1986, has received a 3-year award of approximately $15.8 million from NSF and DARPA to lead research to determine the technology and possible structure of a gigabit network and identify possible end-user requirements for such a network. | high-speed computer networks in the united states, europe, and japan, sept. 1991, gao, us general accounting office

Japan:

One of Japan’s most significant undertakings involves its recently announced plans to invest approximately $260 billion to equip businesses and homes with a broadband Integrated Services Digital Network (ISDN) by the year 2015. | see above

EU

According to these officials, although much of the technology needed to implement a pan-European’network is available, issues concerning how to organize and fund the network still need to be addressed ... In the absence of central leadership, cross-border telecommunications services are difficult and expensive to obtain. Various organizations, such as the European Engineering Planning Group (EEPG) and the Réseaux Associés pour la Recherche Européenne (RARE), an association of networking organizations and users in Europe, are optimistic that these issues can be resolved ...

20 years later, a high performance computing european study compares usa, japan, china and europe, and talks about chances, investments, policy and economy, software and hardware development:

A Strategic Agenda for European Leadership in Supercomputing: HPC 2020 — IDC Final Report of the HPC Study for the DG Information Society of the European Commission, Sept. 2010

maybe one should still set a pointer to the first eu supercomputer initiative debate 1968 - 1972, or so, which brought us  –  nearly  –  unidata. however, nobody meant a concrete machine, but bringing european computer industry to talk to each other on a pan-european level; "the first time", maurice allegre adds. At the time e was a member of french delegación informatique.