Brown University Installs First of Two Cray Research Supercomputers

This is a press release from Oct. 26, 1995 announcing that the Brown University Department of Physics was installing a Cray EL98 and J916.

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Cray:           Mardi Larson, 612/683-3538
Brown:          Professor G.S. Guralnik, 401/863-2623

BROWN UNIVERSITY INSTALLS FIRST OF TWO CRAY
RESEARCH SUPERCOMPUTERS

EAGAN, Minn., Oct. 26, 1995 -- Cray Research announced today
that Providence, RI.-based Brown University has installed the
first of two CRAY(R) supercomputers to be dedicated to the
university's Department of Physics.  According to Cray,
Brown's physics department is the first university physics
department in the U.S. to acquire a Cray system.  Terms were
not disclosed. 

A large-memory (four gigabyte) CRAY EL98(TM) system was
installed this year, to be followed by a CRAY J916(TM) system
scheduled for installation later next year.  These systems are
the first Cray Research supercomputers acquired by Brown and
will be used by Brown University Professors Guralnik,
Kosterlitz, Marston, Tan and other university physicists and
students who are focusing on problems in high-energy and
condensed matter theoretical physics.  These users will run
simulations on the supercomputers to help them learn more
about the basic structure of matter and its interactions.

"Combined with analytic methods, the computational power of
the Cray supercomputers will make an excellent tool for
understanding how microscopic laws determine the higher
level characteristics of matter," said Dr. Brad Marston,
assistant professor of physics at Brown University.  "The Cray
supercomputers will give physicists at Brown a powerful tool
to develop new ideas because of their ability to run the very
complex simulations that are often needed to make predictions
from current theories and ideas," Marston continued.

While these CRAY systems will be used to perform calculations
testing very abstract ideas, in time, the results could become
important for everyday living.

"When we understand something basic about the universe" said
Dr. Gerald Guralnik, professor of physics at Brown, "it
eventually affects the way we live.  That is how we generated
the technological advances we already have today.  The
knowledge that we obtain could be essential for developing
new energy sources as well as leading to new product
developments in the semiconductor and materials industries." 

The CRAY EL98 and CRAY J916 are Cray's compact, air-cooled
supercomputers priced starting at $250,000 (U.S. list price). 
The supercomputers are designed to operate as powerful
simulation servers for compute-intensive problems that
challenge the capabilities of workstations.  Since its
announcement in September 1994, the current CRAY J90 line
has attracted more than 200 orders, with about 40 percent
coming from new-to-Cray customers including from new
industries. 

Cray Research provides the leading high-performance
computing tools and services to help solve customers' most
challenging problems.

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Source: Brown University Installs First of Two Cray Research Supercomputers

Boy Genius Blocks Navy Wireless

Commander Albert C. Gleaves U.S.N. of the Torpedo Station in Newport, Rhode Island, had a problem. The government had installed a new wireless station for ship-to-shore communication but in 1906 they were experiencing interference from a nearby amateur radio operator.

My sign was GR. "GR GR GR," they said, "if you don't stop operating that coil, you will find yourself in the jug shortly." I answered by sitting on the key. I was such a nice boy! - Lloyd Manual, Wireless Age, Dec. 1916.

The Nashville American, Feb. 22, 1906

The Navy investigated and discovered a teenage schoolboy who had converted a hen house into a "ham shack" and equipped it with a home-made transmitter. The meagerness of the radio set startled the professional wireless operators who examined it. A report was filed with the Navy Bureau of Equipment. Some of the components used to build the set were described in The Nashville American and included:

Experimental Wireless Station 1XX

The Radio Club at Brown University dates to the end of the First World War when the United States government lifted restrictions on the private operation of wireless equipment. Student amateur radio operators formed the new club during the Fall semester in 1919.

An early transmitter used on campus was described as "a ½ KW rotary spark set and a two step amplifier" in the September 1920 QST magazine. One of the call signs used was 1LAU which was assigned to student Herbert R. Grimshaw. The emissions from the crude transmitters used by amateurs during this time caused stations in the same geographic area to interfere with each other. President of the club E. Standish Palmer proposed a system for managing the problem:

"Providence has considerable QRM [interference] to overcome and some sort of a control station is being considered. Palmer suggests different hours for the different classes of communication and a visiting committee to go to the stations of the various amateurs who overstep and tune them up. This is a good idea. Help the young fellows out in every way possible. Make them feel as though we are helping and not trying to dictate to them."

Another transmitter was a home-made set with two vacuum tubes. The alternator used to generate the alternating current is not shown in the photo below. It produces an Interrupted Continuous Wave (I.C.W.) which, like the rotary spark gap described above, was used to send Morse code. These transmitters were not capable of voice communications.

Credit: QST, April 1921.

Trilobite Detritus

The Craigleith area of Ontario is well known for its abundance of fossils. In 1992 I visited this locality on the southern shore of the Georgian Bay to search for them. There was a railway cut through the shale near Collingwood. The first slab of rock that I cracked open revealed a cluster of trilobite carapaces. They date to the late Ordovician which is about 445 million years ago.

Closeup of trilobite tail pieces.

Sky Brightness 3

As we saw in part 1 and part 2 of this series the typical measurements of sky brightness in Providence are between about 4.1 - 4.3 nelm (naked eye limiting magnitude) on clear nights. Here is a graph that shows a typical hazy summer night. The readings were taken on the night of July 1st into the morning of July 2nd of 2014 and are in the range that we commonly see. The dashed horizontal line is a somewhat arbitrary divider between typical and darker nights. When the sky brightness is below about 4.3 the observing is much better.

Looking at a graph of the sky brightness doesn't give an intuitive idea of what the sky actually looked like for observing. We can see this by looking at the wide angle views of the sky using the camera mounted on the roof. Here is a time lapse movie from the same night as the above graph.

Sky Brightness 2

In my previous post I began to analyze the data from the sky brightness meter at Ladd Observatory. Now we'll take a closer look at the broader trends. Here is a scatter plot showing the data from the summer and fall of 2013. The plot is a little busy but we're really only interested in the "bottom line" where the data points are at the lowest values. All of the nights are superimposed on one another with the x axis showing hours UTC. This graph summarizes how the sky brightness changes during the course of the night. The many values between 3.7 and 4.3 are due to nights that are more or less hazy. There moisture in the atmosphere scatters light from the city back down to us and causes the overall sky to look brighter.

If we follow the lowest readings there is a definite trend where the clearest nights start off at about 4.2 at the end of twilight and slowly, steadily, decrease to about 4.45 at 4 hours UTC. There is then a small but rather sudden drop to 4.55 after which the slow decrease continues until we are at about 4.6 in the early morning. I'm not sure what is causing the drop at 4 hours but it may be due to city lights that are on a timer. The takeaway here is that the sky is slightly, but significantly, brighter in the early evening. The best time to observe is after midnight local time through the early morning.

Sky Brightness

"The sky above the port was the color of television, tuned to a dead channel."
- Neuromancer, William Gibson, 1984.

At the Ladd Observatory we operate a weather station and a number of other rooftop instruments to monitor the environment. One of them is a sky brightness meter. On a regular basis we use the live data to judge the quality of the sky for observing. It is also used to document long term changes such as the increase in light pollution.

Sky brightness meter
and camera on the roof.

The meter is contained in a weather proof housing next to a wide field sky camera. The camera takes a low resolution image of nearly the entire sky every 10 seconds and these images can then be compared to the brightness readings. I can then verify what the sky looked like when a measurement was taken. When the sky is very cloudy it scatters light from the city and the readings are very bright. Haze or high humidity can also cause elevated readings.

The sensor is too sensitive to take a measurement during the daytime. It starts collecting data shortly after sunset when the sky begins to darken and stops during morning twilight just before sunrise. Last summer I calibrated the meter and we've now collected 300,000 data points in about one year. I thought this would be a good time to analyze what we have so far.

As the Bubbl Bursts

The invention of magnetic bubble memory was once seen as a revolutionary computer development - the wave of the future. It is now a nearly forgotten technology.

"Many persons expect that the most dramatic changes in digital systems will result from magnetic-bubble chips that could well hold a million or more bits in the not-too-distant future. Along with charge-coupled devices, these memories show promise of replacing magnetic tape and disks for small systems." [emphasis in the original]

- Understanding Digital Electronics, Texas Instruments, 1978

One of the more unusual computer objects that I've collected over the years uses this memory. It is called the QSB-11A Bubbl-Board. I was told by the person that sold it to me that it had been used in a system at Los Alamos National Laboratory. I have no idea how it was used. Given the nuclear research conducted there I sometimes wonder if I should check to see if it is "hot."

W9GYR

As a young child I can remember my late grandfather operating a ham radio station in Chicago using surplus military equipment that he obtained at the end of World War II. When I received my own amateur radio license about a year ago I began to wonder when he first became involved in the hobby. I suspected that he started before the war so I started to dig through old FCC publications which listed newly issued licenses. I couldn't find a single mention of his name or the call sign that he was assigned: W9GYR.

My first clue to narrow down the search was a website called Old QSL Cards which has a large collection of the postcards that amateur operators send each other to confirm that they had made a radio contact. QSL is early radiotelegraph shorthand for "I am acknowledging receipt" of a wireless message. They had a card from my grandfather that was dated 1939.

QSL card from my granfather from Jan. 26, 1939.
Scan courtesy of Old QSL Cards.

"The Red Skies" of 1883

"It is impossible not to conjecture a connection with the volcanic eruption in the Sunda Straits, by which, on Aug. 26, the island of Krakatoa disappeared wholly from the face of the earth."

"The terrible nature of this outburst can hardly be realized: the sky was darkened for several days, the noise was heard two thousand miles, magnetic disturbances were noted, the tidal wave was distinctly felt at San Francisco, and the atmospheric disturbance was sufficient to cause marked barometric fluctuations, which were noted by the barographs on the continent, in England and America, for several succeeding days."

- W. Upton, "The Red Skies." Science, 11 January 1884

During the fall of 1883 there was a remarkable atmospheric phenomenon which "attracted great attention not only from the general public, but from scientific men, who have endeavored to give a satisfactory explanation of it." At the time that he wrote those words Winslow Upton had just accepted the position of Professor of Astronomy at Brown University. Prior to this he had been Assistant Professor of Meteorology in the U.S. Signal Service from 1881. The phenomena that he endeavored to explain were the "recent fiery sunsets" seen throughout the world.

The Scream (1893) by Edvar Munch
(National Gallery, Oslo, Norway)

There were three different hypotheses as to the cause of the "blaze of brilliant red light" seen at sunset. One possibility was refraction through water vapor in the atmosphere. Another suggestion was that the Earth was passing through a cloud of meteoric dust. But the most likely explanation, as improbable as it sounded at the time, was that a large amount of dust from the eruption of the volcanic island of Krakatoa had been thrown up to such a height that it slowly spread around the globe. Microscopic examinations of residue from snow in Madrid and a rain-storm in Holland seemed to confirm the volcanic hypothesis by revealing the presence of particles that were similar in composition to the ash from Indonesia.

The sight of the blood red sky seen at sunset may even have inspired the Norwegian artist Edvar Munch who "felt a great, unending scream piercing through nature."

Note: I originally published this on the Ladd Observatory Weather Underground blog in 2011.