Supercomputers/Systems/Bassi
USA · decommissioned · hpc
Bassi
Also known as NERSC IBM p575 Bassi
Operated by Lawrence Berkeley National Laboratory .
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: 1263 of 1345 systems have a readable citation that names them, and 56 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
- 6.42 TFlop/s
- Rpeak
- 7.42 TFlop/s
- Rmax ÷ Rpeak
- 86.5%
- Cores
- 976
- Power
- 159 kW
- Per watt
- 0.0 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 | - IBM eServer pSeries p5 575 cluster | IBM | - | Reported | top500.orgweb.archive.org |
| CPU | - IBM POWER5 dual-core 1.9 GHz, 888 compute processors in 111 nodes of eight | IBM | - | Reported | top500.org |
| Interconnect | - IBM Federation HPS switch with two-link network adapter per node | IBM | - | Reported | web.archive.org |
| Operating system | IBM AIX Operating systems Unix (System V-derived) · Proprietary IBM AIX | IBM | - | Reported | top500.org |
The read
NERSC's IBM p575 POWER5 cluster, named for Laura Bassi. NERSC's news item says it opened for production on 9 January 2006 with 888 processors for parallel computing, and NERSC's archived Bassi page describes 888 processors in 111 nodes on IBM's Federation switch at 7.6 GFlop/s peak per processor. A NERSC archived page (web.archive.org/web/2010/http://www.nersc.gov/nusers/systems/bassi/) says Bassi was decommissioned on 7 April 2010 and replaced by the Carver cluster. TOP500 lists 976 POWER5 1.9 GHz cores with 6.42 TFlop/s Rmax, 7.42 TFlop/s Rpeak and 159 kW on AIX, ranked 53rd in November 2005, 72nd, 102nd, 196th and 425th in November 2007 (its last list). The TOP500 core count includes processors beyond the 888 compute processors NERSC cites.
Timeline
- 2005-11 List debut at #53 (November 2005) source
- 2006-01-09 First operational source
- 2010-04-07 Decommissioned source
Public list appearances
Pointers only: rank and edition, linking to the canonical entry. We do not reproduce list tables. See sourcing policy.
Change history
- 2026-10-09 Added Bassi
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 |
|---|---|---|
| web.archive.org | names system only | - |
| top500.org | names system only | - |
Checked 2026-10-13 by pnpm verify. Re-run it and the table changes with the web.
Further reading
Operating a supercomputer
Acceptance testing, why "installed" and "in production" are six months apart, and the machine lifecycle.
Inside a node
Latency-optimised versus throughput-optimised processors, NUMA, and the end of the host-to-device copy.
The interconnect
Topologies, why latency and tail behaviour matter more than bandwidth, and how the fabric market consolidated.