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About Robert G. Brown

Things on the site itself that may be of interest to students or philosophers of any age or generation include complete online books of poetry, various support materials for the study of physics, and links related to beowulfery. All materials on this site that are authored by Robert G. Brown are Copyright 2004. The details of their Open Public License (modified) can be viewed here. If you use or enjoy anything at all on this site -- free textbooks, stories, programs, or other resources, consider hitting to help spread the word so others can find it as well. Note, Robert G. Brown is generally either rgb or rgbatduke on many external sites crosslinked here.

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The Tao of Beowulf Computing

In a little known book of ancient wisdom appears the following Koan:

The Devil finds work
For idle systems
Nature abhors a NoOp

The sages have argued about the meaning of this for megacycles, some contending that idle systems are easily turned to evil tasks, others arguing that whoever uses an idle system must be possessed of the Devil and should be smote with a sucker rod until purified.

I myself interpret "Devil" to be an obvious mistranslation of the word "Daemon". It is for this reason, my son, that I wish to place a simple daemon on your system so that Nature is satisfied, for it is clear that a NoOp is merely a Void waiting to be filled...

This is the true Tao.

About Robert G. Brown


Born March 29, 1955 in Raleigh, North Carolina.
Married in 1979 to Susan Foster Isbey, MD.
Three sons:
Patrick O'Dowd Brown, b. 1987
William Brinkman Brown, b. 1990
Samuel Gibbins Brown, b. 1995
Lives in Durham, N.C.


B.S. from Duke University, 1977

Magna Cum Laude, four years on the Dean's list with class honors. Majors were Physics and Philosophy, with a minor interest (eight course credits, four at the graduate level) in Mathematics.

PhD. from Duke University, 1982

General area: theoretical and mathematical condensed matter physics. Ph.D. dissertation: ``The position space Green's function and its application to a non--muffin--tin band theory'' available from Duke University Library.

Professional Accomplishments

Curriculum Vitae

Available in a Web/HTML, a Postscript or a PDF image.


During the interval from 1982-present, research accomplishments include: the first correct derivation of a formally exact, non-muffin-tin multiple scattering theory (which effectively eliminates both the muffin-tin approximation and the need for "near field" corrections from stationary multiple scattering theory in most solid state and quantum chemistry calculations); the one of the first applications of microscopic simulation techniques to problems in nonlinear quantum optics; the first correct Monte Carlo evaluation of the dynamic critical exponents and properties of the classical Heisenberg (O(3)) model; a careful examination of the role of the Central Limit Theorem in obtaining unbiased error estimates from importance sampling Monte Carlo driven by a variety of Markov processes; and most recently, the most precise evaluation of the static critical exponents of the classical Heisenberg model ever done.

This latter calculation utilized "all" of a 2+ GFLOP parallel supercomputer for six straight months to significantly advance the precision (by several significant digits) obtained in previous calculations. It used several distinct random number generators and Monte Carlo methodologies to obtain results that are clearly reproducible and independent of method. This calculation revealed a surprising disparity between the exponents predicted by Monte Carlo combined with finite size scaling techniques and those predicted by the renormalization group. In particular, the specific heat for the model was found to be singular (with a small positive exponent) rather than negative (associated with a "cusp" nonanalyticity at the critical temperature). This disagreement has yet to be addressed or resolved.

Systems Engineer/Programmer

From 1987 to the present, worked as a systems programmer/administrator for the subnet on the Internet, in addition to regular duties teaching and doing research. This heterogeneous subnet grew from two or three Unix hosts on a single ethernet segment with a handful of Macintoshes and PC's to nearly thirty Unix hosts, fifty Macintoshes, and ten PC's on a five-segment bridged ethernet during this interval. In addition, acted as a systems engineer consultant (unpaid) to start subnets and provide initial training for neophyte systems administrators in the department of Psychology at Duke, and the department of Physics at NCCU and (paid) the department of Chemistry at Duke. The Chemistry and Physics subnets are considered among the best designed and administered at Duke.

In 1993-1994, acted as one of the faculty representatives on the "Project Hermes" team designing an enterprise email and infrastructure support system for the University. It can safely be said that a considerable amount of the final hardware design for this project derived from the analyses performed by RGB for this workgroup.

In 1994 also sat on a Security workgroup whose charge was to provide the University with a coherent written security policy. In this capacity, collected a number of useful white papers on network and computer security and wrote most of the security policy (postscript) document that, unfortunately, has yet to be formally implemented. However, it still stands as the only set of guidelines that are actually written down for establishing security procedures and sanctions at the University.

In 1994 reviewed and (together with Rob Carter and Andrew Gallatin) effectively rewrote from scratch the systems engineering and design of a proposed upgrade of the Undergraduate Computing Clusters (postscript document). This upgrade proposal has served as the basis for the design that was eventually adopted and that has been, for the most part, overwhelmingly successful. In particular, the current cluster system is scalable at a known, predictable cost and has significantly improved the availability of computing and network access resources to the entire undergraduate student body.

From 1990 to the present, served as an informal (mostly unpaid) consultant many individuals in the Duke University Computing landscape: Gail Corrado (assistant Vice Provost in charge of computing), Jesse Eversole (assistant Vice Provost in charge of computing), Melissa Mills, the assistant dean for Arts and Sciences computing, Betty Lecompagnon (Vice Provost, CIO), Richard Palmer and Robert Wolpert (ITAC chairs), Chris Cramer (Chief Security Officer) and many others. Sometimes my advise was even sought;-)

From 1995 on, has been extremely involved in the beowulf movement -- the development of commodity off the shelf (COTS) parallel supercomputers based on the Linux operating system. Built the original beowulf at Duke, Brahma, a more recent beowulf named Ganesh, set up the Duke Beowulf User's Group and has supported countless others seeking to build beowulfs.

In 1995 co-founded Market Driven Corporation. This was originally a company dedicated to predictive modeling and data mining using a highly advanced neural network, Discovertm written by rgb. More recently the company has evolved into a generalized web services company where predictive modeling is just one component of its service offerings.

Currently is helping Immaculata Catholic School build its technology infrastructure as chairperson of its information technology committee (and principal hands-on volunteer systems administrator).

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This page is maintained by Robert G. Brown, available at rgb at phy dot duke dot edu. This address is also associated with rgbatduke in e.g. stumbleupon or google code, in case you are looking.