UTokyo SR8000/128

Also known as Hitachi SR8000/128

Operated by University of Tokyo at University of Tokyo Computer Centre .

Phase 1 seed dataset, compiled by hand. These rows were built from public operator, laboratory and vendor sources. A mechanical second-reader pass has since fetched every cited source: 1092 of 1153 systems have a readable citation that names them, and 40 are genuinely weakly sourced. Every claim carries its source and a confidence tier. Treat anything below verified as a lead, not a citation.

Measured performance

Rmax: 873.0 GFlop/s
Rpeak: 1.02 TFlop/s
Rmax ÷ Rpeak: 85.3%
Cores: 128
Power: -
Per watt: - GF/W

Figures are as last publicly reported for the configuration described below, not a live measurement. Where a system was upgraded in place, the post-upgrade configuration is shown and the earlier one appears in the timeline.

What this machine is made of

One row per supplier relationship. “Supplier at build” is the company that shipped the part at the time; where that company has since been acquired, the parent it rolls up to today is shown beside it. That distinction is what makes ticker-level aggregation possible across a thirty-year dataset.

Role	Part	Supplier at build	Quantity	Confidence	Source
Integrator	- Hitachi SR8000/128	Hitachi 6501TSE	-	Verified	top500.org cc.u-tokyo.ac.jp
CPU	- 128 SR8000 nodes, 1,024 GFlop/s peak	Hitachi 6501TSE	128 reported	Verified	top500.org cc.u-tokyo.ac.jp
Interconnect	- Multi-dimensional crossbar	Hitachi 6501TSE	-	Reported	top500.org
Operating system	Hitachi HI-UX/MPP Operating systems Unix (Mach 3.0 microkernel), Hitachi-customised · Proprietary HI-UX/MPP	Hitachi 6501TSE	-	Reported	top500.org

The read

The 128-node Hitachi SR8000 at the University of Tokyo's Information Technology Center, which ran from 1999 to 2005 before the 144-node SR8000/MPP. The centre's past-systems page gives 128 nodes with 8 GB each and 1,024.0 GFlop/s peak, and TOP500 agrees on 1,024 GFlop/s peak and adds 873 GFlop/s Rmax, fifth on the November 1999 list, with the machine listed from June 1999 to November 2004 under HI-UX/MPP on a multi-dimensional crossbar. TOP500 is the only source for Rmax, so the tier is reported.

Timeline

1999 First operational source
1999-11 List debut at #5 (November 1999) source
2005 Decommissioned source

Public list appearances

Pointers only: rank and edition, linking to the canonical entry. We do not reproduce list tables. See sourcing policy.

#5: TOP500, November 1999 →

Site & facility

University of Tokyo Computer Centre

Location: Tokyo, Japan
Commissioned: 1996

top500.org top500.org

Change history

2026-10-02 Added the University of Tokyo's Hitachi SR8000/128, fifth on the November 1999 TOP500

Source check

We fetched this system's own citations and recorded whether each page actually mentions it. This is a corroboration signal, not a fact check, and it is published so you can see how well the sourcing holds up rather than take it on trust.

Cited source	Result	Found on the page
top500.org	names system and part	Hitachi HI-UX/MPP
cc.u-tokyo.ac.jp	does not name this system	Hitachi HI-UX/MPP

Checked 2026-10-09 by pnpm verify. Re-run it and the table changes with the web.