This is Arecibo Calling...

"Ironically, the globular cluster at which the signal was aimed won't be there when the message arrives. It will have moved well out of the way in the normal rotation of the galaxy." - It's the 25th anniversary of Earth's first attempt to phone E.T. Cornell Chronicle, Nov. 12, 1999

My estimate of the Arecibo transmission from a couple of years ago.
It looks like we may have missed...

In 1974 a ceremony was held to dedicate a major upgrade to the radio telescope at Arecibo Observatory. As part of the festivities the telescope was used to transmit a message towards Messier 13, the Great Globular Cluster of stars in the constellation Hercules.

"Scientists Hope to Reach Hypothetical Civilization in a Cluster of Stars" - New York Times, Nov. 20, 1974

System Ready

In a previous post I described the power requirements of the Cray J916 and the importance of the Central Control Unit (CCU) monitoring for faults. This is rather critical as the machine won't function properly unless these hardware status signals check out.

The back of the I/O Subsystem in the Peripheral Cabinet. This is the cleanest cable management system I've ever seen, but tracing cable paths while re-wiring the system was time consuming.

With the system re-cabled we can power it up and begin testing the hardware. We noticed that the CCU contains rechargeable D size batteries. Yes, we received a donated Cray and batteries were included! They were, of course, very dead. The system had been unplugged for a long time.

Half a Million Years of U.S. History

"Gutzon Borglum's design intentionally left three extra inches of granite on the surface of the sculpture so that nature, in the form of wind and water erosion, would finish carving Mount Rushmore for him over the next 20,000 years." - Matthew Buckingham in Cabinet Magazine

Workmen on face of Geo. Washington, Mt. Rushmore
Source: Library of Congress

I've stumbled upon claims similar to this a number of times. The amount of stone and the number of years varies. But, I've never seen a footnote or reference to a source that confirms that the meme is true. I found the above quote about 5 months ago in a post titled "Half a Million Years of U.S. History" on the Long Now Foundation Blog. My curiosity compelled me to spend some time digging for an answer. I wrote a reply in the comments section of the blog which was never published. Perhaps I should have waited a bit longer, given the nature of the Long Now project. I'm impatient... So, I'm going to publish what I found here:

Be a Computer Crusader!

The Retro-Computing Society of RI will be featuring the Cray Jedi at the next open house on Saturday July 19th at our facility in Providence. This fall is our 20th anniversary. (If you are looking for gift ideas we prefer the modern platinum to the more traditional china.)

A short time after our group formed we made arrangements for a private tour of The Computer Museum in Boston. Our member Carl has a detailed write-up of the visit and the collection that we saw. Not long after our 1996 visit TCM closed and the collection was moved to a new home on the west coast which became the Computer History Museum.

A Data General poster depicting the Nova and Eclipse minicomputers as superheros.
From the collection of the Computer History Museum.

Another of our members created The Retro-Computing Lab Millspace Tour which gives a nice snapshot of what we were doing between late 1996 when we moved into the Eagle Street facility and mid-1998 when the page was last updated. Warning:

This page may take some time to load if you are viewing graphics.

Under the Covers

What's inside a Cray J90? I'm going to take a pause in the restoration to "pop the hood" and describe what's under the covers. Here we have the two cabinets bolted together with the doors and most of the panels removed. On the right is the Processing Cabinet and on the left is the Peripheral Cabinet.

The Cray J916 with the front doors and many of the filler panels removed.

The Processing Cabinet has a Central Control Unit at the top which has LEDs that display status and fault conditions. Below that is a plenum space for the cooling blower intake and dust filters. Next is the backplane (the Processor and Memory Modules are inserted from the back.) Under that is the blower which exhausts out the back. At the bottom are the 48 volt DC power supplies.

The Peripheral Cabinet is moderately configured with plenty of space for expansion. In the center is the I/O Subsystem VME Chassis which contains two VME backplanes. Each contains a SPARC single-board computer which functions as an I/O Processor (IOP.) The remaining VME slots contain the system interfaces including Ethernet, disk controllers, and the I/O Buffer Boards (IOBB) that transfer data from peripherals to the J90 processors and memory. At the bottom are two disk arrays.

Galaxy Collision

Two galaxies colliding and merging.

Generated using the simulation code GADGET-2 running on a small number of nodes on the HPC cluster at the Center for Computation & Visualization and rendered using IFrIT. The T= shows simulation time in billions of years.

The source code computes the gravitational forces between the ordinary matter within the galaxies and the dark matter halos surrounding them. The dark matter is not rendered in this visualization. The code was created in 2000 and last updated in 2005. It is optimized for massively parallel computers with distributed memory.

A somewhat better quality version can be viewed here.

Kilowatts, Control Cables, and Cooling

The Retro-Computing Society of RI is located in the Atlantic Mills in the Olneyville neighborhood of Providence. We have a 1,500 sq. ft. facility in a mixed-use complex that was originally a worsted mill during the industrial revolution. It suits our needs quite well with amenities like a loading dock and a freight elevator. As I described in the previous installment, the system weighs more than a half ton. It was surprisingly easy to move as it has well designed casters that allow it to be smoothly rolled around. Now that it has arrived we need a plan to plug it in. Our electrical panel was a bit under-powered for running the Cray.

The back of the J916 with the two cabinets bolted together. Each cabinet has an AC power entry box which we had removed to prevent damage to the power cord during the move.

The system requires three-wire, single-phase, at 240 volts. A fully configured Processor Cabinet could draw a maximum of 4,200 watts while a full Peripheral Cabinet could draw up to of 3,600 watts. Our J916 is a moderately configured system which is about one half full. There is plenty of space for expansion to add additional drive bays, for example. There is a helpful Electrical Requirements Worksheet in the Preparing for a System Installation manual. For this configuration we calculate that both cabinets draw a total of about 2,000 watts or so. The property manager scheduled an electrician to upgrade our service and install the receptacles. We also made other changes to make it easier to power up some of our other machines that we haven't been able to run recently. The work was completed on June 30, 2014.

Customer Name (if not confidential)

It was about four years ago when I first learned that there was still a Cray in the Department of Physics at Brown University. The machine was in the same building as my office; for years I had no idea it was sitting idle just a few floors above me. My colleague Prof. Ian Dell'Antonio facilitated the donation to the Retro-Computing Society of RI. He uses the high energy theory cluster for research on observational cosmology and gravitational lensing.

My other computer is a Cray...

In my previous installment I described the Theory Computing Cluster machine room where the Cray J916 had been used for high energy theoretical physics research at Brown University. It was installed in 1996. I'm not sure exactly when they stopped using it. I was told that it was difficult to program and had been unused for some time. Supercomputers tend to have a rather short shelf life.


We first moved the Cray to Brown's Science Center where it was on display for a few years. Before it could be safely moved I had to "split" the cabinets. There is one Peripheral Cabinet housing the I/O Subsystem and disk arrays. The second cabinet is the mainframe, or Processing Cabinet, which contains the CPUs and memory. The Cray documentation sometimes uses the archaic definition of mainframe to refer to the primary frame (or cabinet) that contains the central processor. The Oxford English Dictionary cites a usage from Honeywell in 1964 and gives this definition:

mainframe, n.

2. Computing. Originally: the central processing unit and primary memory of a computer. Now usually: any large or general-purpose computer, esp. one supporting numerous peripherals or subordinate computers.

The Theory Cluster

The use of high performance computers has had a tremendous impact on the progress of science. Theses machines have enabled us to advance our understanding of everything from elementary particles to the large scale structure of the universe. The fastest systems of any era are referred to as supercomputers. For many years supercomputing was synonymous with the machines designed by Seymour Cray at Control Data Corporation and later at Cray Research.

Supercomputers have always been very large and expensive. They require a large amount of electrical power and exotic cooling systems. They are typically a shared resource only used at large government research laboratories and academic institutions. By the late 1980s a new class of minisupercomputer was introduced. With a price starting at less than one million dollars these smaller air-cooled systems could exclusively be used by a research group or academic department.

In the mid 1990s the Brown University Department of Physics was the first physics department in the U.S. to acquire a Cray system. In Augusts 1995 a Cray EL98 was installed. This was followed in late 1996 with the installation of a Cray J916. They were used for high-energy and condensed matter theoretical physics. Details of the research are at the Computational High Energy Physics group page.

The Theory Cluster Machines webpage of the High Energy Physics Group at Brown University. The page was created in late 1995 and includes a publicity photo of the Cray EL98 that had just been installed. The snapshot was captured using NCSA X Mosaic on a SPARCstation 5 running Solaris.

Shatter Cone

Shatter Cone from the Sudbury Basin.

In 1992 I attended a conference on Large Meteorite Impacts and Planetary Evolution in Sudbury, Ontario. The highlight of the visit was the field trip that we took to view the geological evidence of a massive meteorite impact nearly two billion years ago. The impacting object was likely in the range of 10-15 km (about 1/2 - 1 mile) in diameter. It left an oval basin which is 60 by 30 km (40 by 20 miles) containing breccia, a rock formed from the broken fragments of pre-impact bedrock. There are also rocks that have been shattered by the shock wave from the impact. These are only found in impact craters and are called shatter cones.