If you’re a regular AllThingsD reader, you’ve already been introduced to the world’s most power supercomputer: It is the Fujitsu K Computer, which the Japanese computing concern disclosed earlier this month, and it runs in Japan’s quasi-public research institution RIKEN. That’s it in the picture above.

It’s capable of performance as high as 10.51 petaflops, or 10.51 quadrillion floating point operations per second. The same machine had been rated in the top spot on the list before, but was less powerful then, because it was still being assembled, and then capable of only 8.16 petaflops.

The machine is based on SPARC chips — the chips for which Sun Microsystems, now part of Oracle, gained such renown. Fujitsu has been building SPARC chips under license and using them in its own servers and supercomputers for years. In this case, there are 705,024 SPARC64 processing cores in action. And if my memory is correct, the chips in question each have four cores on board, meaning there are 176,256 individual processing chips in the machine.

It’s the first machine on the Top 500 list to venture past the 10-petaflop milestone; however, work is underway in the U.S. on a machine known as Titan, which will supposedly break the 20-petaflop mark sometime next year.

In the meantime, the second most powerful machine in the world is in China. The Tianhe-1A system took the top spot on the list a year ago — and in the process, caused President Obama such consternation about the state of American leadership in innovation that he mentioned it in his State of the Union address to Congress. Its performance reaches 2.57 petaflops and it’s powered by a combination of Intel-made Xeon processors and Nvidia graphical processing units.

In fact, the supercomputers in the top 10 spots on the list are otherwise unchanged from the list released in June.

At No. 3 is Jaguar, the system at the Oak Ridge National Laboratory that is being rebuilt into the machine called Titan, which I mentioned before. It’s a system built by Cray primarily around Nvidia GPUs and Opteron processors from Advanced Micro Devices. Its current performance is just shy of 1.8 petaflops.

The No. 4 system is in China. It’s called Nebulae and is at the National Supercomputing Centre in Shenzen. Its performance is just short of the 1.3-petaflop mark. No. 5 is called Tsubame 2.0, and is at the Tokyo Institute of Technology in Japan.

Chip companies in particular like to crow about the use of their products in the systems that wind up on the list. That makes this a banner day for Intel. Of the 500 systems on the list, 384 of them — 77 percent — use Intel chips. Chips from AMD, Intel’s main rival, are in 63 systems.

It’s a banner day for Nvidia, too. Its GPU chips can be found in 35 systems, more than double the number from the previous list. GPUs were invented to make the graphics in computer games more stunning and realistic; as such, it meant they were, from the beginning, pretty good at performing a certain type of math problem known as a floating point operation. It turns out that the people who run supercomputers do a lot of floating point operations — or FLOPs — too. So as GPUs have gotten more powerful, they’re finding their way into an ever-larger number of the world’s top supercomputers. Two supercomputers on the list use GPU chips from AMD’s graphics chip unit, ATI. Two more use IBM’s PowerCell architecture, which is a sibling of the Cell processor chip found in the Sony PlayStation 3.

President Obama shouldn’t feel so bad about the U.S. not being in the top spot. For one thing, practically all of the systems on the list are built on American-made technology. And among the systems that can reach 1 petaflop in performance or more, the U.S. has five, more than any other country. China and Japan have two each, and France has one. And the U.S. has more supercomputers on the list than any other country: 263. European countries have a combined 127; China has 75 and Japan has 30.

Intel may furnish more chips to the Top 500 list than anyone, but the king of the systems vendors on the list is unquestionably IBM, followed by Hewlett-Packard. IBM built 223, or more than 44 percent, of the machines on the list; HP built 140 of them. IBM also led the performance pack: Its machines are responsible for more than 27 percent of the total. Fujitsu, which made the list-topping K Computer, was in second place, with 14.7 percent. Cray and HP were in a statistical dead heat, with about 14 percent each.

Here’s a link to the full list, and a bunch of other things related to supercomputing.

Oak Ridge National Lab's "Jaguar" computer

Despite the fact that the Chinese system was built largely with American-made or American-designed components, the news came as a bit of a blow to American pride, and even caught the attention of President Obama, who kvetched about it in January’s State of the Union address.

By June (the list is updated twice a year) the Chinese machine had fallen to second place, its crown seized by a supercomputer in Japan, relegating the top supercomputer in the U.S. to third place.

Today, the Oak Ridge National Lab in Tennessee, part of the U.S. Department of Energy, will announce plans to build a system that has a good shot at reclaiming the top spot. The machine will be named “Titan,” and its primary computing engine will be the Tesla chip from Nvidia, the company best known for turning out chips that enhance the graphics of games on personal computers.

Nvidia has been making inroads in high-performance computing for some time. Earlier this year I wrote about how the Tesla chips were helping Lucasfilm make movies faster.

I talked with Steve Scott, the CTO of Nvidia’s Tesla business unit, who told me that the Titan machine will be 10 times more powerful than the current Jaguar machine, and that 85 percent of its computing power will come from Nvidia chips, while the remaining portion will come from conventional CPU chips from Advanced Micro Devices.

Why GPUs and not CPUs? It turns out that graphics chips are really good at doing a certain kind of math known as a floating point operation, much faster than a typical CPU chip from Intel or AMD found inside a PC or server.

It’s also an issue of power. For years, as chips and the transistors on them have shrunk, the amount of power required to send pulsing through them has dropped as well. Scott says that is no longer the case. “We’ve reached the point where processors have become power constrained. If you pack all the transistors that you can onto a chip and run it as fast as you can, the chip will melt. We’ve entered a time where performance is constrained by power, and its only going to get worse, so you need processors that are power efficient,” he says. “It’s a fundamental sea change in the underlying technology of high performance computing.”

GPUs, originally designed for gaming and professional graphics applications like editing movies and visualizing complex problems for engineers and scientists, are inherently designed to perform several repetitive tasks at once. In explaining this, I always think back to the old saying “many hands make light work,” though here it’s applied to computing. Two people who divide up the task of folding a pile of laundry get it done faster than one. And four people will get it done faster than two.

Basically, a GPU chip is designed to render what happens to every pixel of a computer screen 50 times a second or even faster. Essentially, lots of small computational jobs are carried out at once. It’s called parallel computing, and, fundamentally, CPUs chips aren’t as good at it as GPU chips. CPUs are better at doing one job at a time, getting it done really fast, and then moving on to the next one. Generally speaking, Scott says, GPUs are about eight times faster at floating point operations than CPUs.

For Nvidia it will be a return trip to the top spot. China’s supercomputing champ, the Tianhe-1A at National Supercomputing Center in Tianjin, which is now ranked No. 2 in the world, uses Nvidia GPUs. This certainly got the world’s attention concerning the potential for GPUs in high performance computing.

The plan at Oak Ridge calls for Titan to have 18,000 nodes, each with an AMD CPU chip coupled with an Nvidia Tesla GPU. Most of the heavy lifting will be done by the GPUs, Scott says. Its total computing capacity will top out at 20 petaflops. FLOPS are floating point operations per second. “Peta” refers to how many the system can do every second: In this case, the answer is 20 quadrillion. Just because I can — and because it’s one of the rare cases where I get to use a number that’s larger than the national debt — I’m going to write that number out: 20,000,000,000,000,000.

And what will it be used for? While many of the Department of Energy’s computers are used to simulate nuclear explosions that are no longer allowed thanks to the Test Ban Treaty, this one won’t be. The mission at Oak Ridge, Scott says, is to advance the boundaries of science. Scientists will use it to model climate change, and to predict the results of different methods of mitigating it. They’ll also use it to design engines, study biology and genetics, and explore the possibilities of using nuclear fusion for energy. If you have interesting scientific work to do that requires this kind of computing oomph, you can even write a proposal explaining how you’d use it.

In the first phase of Titan’s deployment, which is already under way, Oak Ridge will upgrade its existing Jaguar supercomputer with 960 new Tesla chips. In a second phase, expected to start next year, Oak Ridge plans to deploy the 18,000-node Tesla-based system.

Down the road, the hope within supercomputing circles is that performance improves to the point where we’re no longer talking petaflops, but exaflops, or quintillions of floating point operations every second. The government is already working on that, and earlier this year President Obama asked Congress for $126 million in the federal budget to begin research to work on ways to get there by 2018. The biggest problem: How to supply enough electrical power while delivering the computing muscle. Today’s announcement by Oak Ridge is a big step in that direction, but there are still 981 more petaflops to conquer.

What could be better than listening to legendary Apple co-founder Steve “Woz” Wozniak wax poetic about his first and favorite gadget–which turns out to be a transistor radio?

Well, doing it inside the newly renovated Computer History Museum in Mountain View, Calif., certainly raises the geek factor to 10.

The museum has spent the last five years planning and installing “Revolution: The First 2,000 Years of Computing” and will open the doors to the public on January 10, 2011. That’s “011011,” Woz reminded the small crowd of journalists invited for an early tour of the new Silicon Valley facility.

The museum has more than doubled its public space to accommodate the new exhibit, which includes an impressive collection of the rare, revolutionary and ridiculous–mostly relating to computing from the 1950s onward.

The whole shebang was largely funded by Microsoft co-founder Bill Gates, whose name features prominently in the signage.

Woz led a tour that highlighted some of the machines that meant most to him. He recounted hours spent at the IBM Model 026 punch card machine, and fawned over a Honeywell Kitchen Computer.

That device was originally sold by Neiman Marcus, complete with mod ’60s styling and bearing the “Mad Men”-esque slogan: “If only she could cook as well as the Honeywell computes.”

Woz said it was the machine that inspired him to believe computers could be attractive things for the home.

After a long meander through many, many more Woz-ly musings, the tour ended at the Homebrew Computer Club exhibit, complete with an Apple 1–signed by Woz–basically identical to the one that recently sold at Christie’s of London for $210,000. (Woz flew there and signed that one too.)

Once open, the expanded museum promises to be the perfect spot to take that über-geeky date, or just wander and reflect amidst hundreds of miles of wire and mountains of transistors.

No word on whether Woz will also be on permanent display.

He seemed to enjoy it, but you can judge for yourself by checking out our highlight video reel from the tour, complete with an interview about Woz’s first and favorite gadget, the coming robopocalypse and the iPhone as a future historical artifact.

Enjoy: