Building A 96-Core Ubuntu ARM Solar-Powered Cluster Building A 96-Core Ubuntu ARM Solar-Powered Cluster

Due to my past ARM Linux benchmarking on Phoronix that they have followed, their use of the Phoronix Test Suite, and my experience with Linux benchmarking and performance testing in general, I was invited over to MIT to help with this 96-core ARM build after having collaborated with them for a few months. This cluster / super-computer was built around 48 PandaBoards.

The bulk of the PandaBoards were not the ES model (I brought my collection of PandaBoard ES models as back-ups for the PandaBoard nodes that failed), but just the vanilla model. The non-ES model packs a Texas Instruments OMAP4430 with a dual-core 1.0GHz dual-core Cortex-A9 processor. The GPU and CPU of the PandaBoard ES with its OMAP4460 are at higher clock speeds, but aside from that it is very similar to the OMAP4430 model.

WLAN-Mesh als Notfunknetz | heise online

WLAN-Mesh als Notfunknetz | heise online
Mit einer Wardriving-Aktion untersuchten Forscher der TU Darmstadt, wie sich WLAN-Router in einem 0,5 km2 großen Block der Heimatstadt verteilen. Dabei erfassten Kamill Panitzek, Immanuel Schweizer, Max Mühlhäuser und Kollegen die periodisch ausgesandten Anwesenheitssignale (Beacons) und bestimmten die ungefähre Position jeder der 1971 gefundenen WLAN-Zellen mittels Multilateration. Es ergab sich, dass die Zelldichte hoch genug ist, ein vermaschtes Funknetz (WLAN-Mesh) zu bilden, bei dem die Router Daten per Funk untereinander statt über das kabelgebundene Breitband-Netz weiterleiten.

Wenn man nun die allgegenwärtigen WLAN-Router mit einer erweiterten Firmware ausstattet, damit sie parallel zum vorhandenen internen Funknetz per Multi-SSID eine zweite, logisch getrennte WLAN-Zelle aufspannen, bekämen Ersthelfer bei Großunfällen oder Katastrophen einen zusätzlichen Kommunikationsweg. Dieses Detail beherrschen zahlreiche WLAN-Router mit ihren Gastnetzen zwar schon heute.

[1203.2847] Demonstration of Communication using Neutrinos

[1203.2847] Demonstration of Communication using Neutrinos
Beams of neutrinos have been proposed as a vehicle for communications under unusual circumstances, such as direct point-to-point global communication, communication with submarines, secure communications and interstellar communication. We report on the performance of a low-rate communications link established using the NuMI beam line and the MINERvA detector at Fermilab. The link achieved a decoded data rate of 0.1 bits/sec with a bit error rate of 1% over a distance of 1.035 km, including 240 m of earth.

Molybdenum Blog by Greg Laughlin

Molybdenum Blog by Greg Laughlin
In 1993, the price of molybdenum was in free fall, and in 1994, it would reach a low of $3,510 per metric ton ($1.59 per pound). The mine was laying off workers and was in danger of closing.In a world with blogs on every conceivable topic, molybdenum, element #42 seems a natural choice. As the posts come out, the somewhat eclectic scope of my interest in this metal should gradually become apparent.

systemic / OKLO

systemic / OKLO
The Systemic web log at is written by Greg Laughlin, Professor of Astronomy and Astrophysics at the University of California, Santa Cruz.

Systemic reports recent developments in the field of extrasolar planets, with a particular focus on observational and theoretical astronomical research work supported by the NASA Astrobiology Institute, and by the Foundational Questions Institute (FQXi). All of Laughlin’s grant-supported research results are published in the peer-reviewed astronomical literature, and are accessible through the NASA Astrophysical Data System.

Laughlin is also author of, a web log dedicated to the element molybdenum (interpreted broadly).

Sverre J. Aarseth: Astronomy

Sverre J. Aarseth: Astronomy
My research into numerical simulations of many-body (N-body) gravitational interactions spans over 40 years, and is reported in several publications and my book. I have developed a set of FORTRAN codes which describe the dynamics very closely, and these are regarded by many as the de facto standard. I have explained below how you can download these codes for execution on your local computer system.