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Pi calculated to its ten trillionth digit

It took more than a year but a Japanese math enthusiast has used a a home PC to calculate the ten trillionth digit of pi, breaking a record set a couple of years ago by a supercomputer.

Unless my high school math memory is off, Pi describes the ratio of a circle's circumference to its diameter. Mathematicians generally rounded off to just two places, which brings the number to 3.14. Shigeru Kondo was assisted in the feat by Northwestern University grad school student Alexander Yee, who wrote the software. On his blog, Kondo noted that the team's pursuit of its goal often got sidetracked due to several hardware failures.

"Over the course of the computation, there were multiple hard drive failures. Each of which required us to roll the computation back to a previous checkpoint. The result was approximately 180 days of lost time," he wrote.

The 10-trillion pi output screen

All told, the pair devoted 371 days of computation to the task.

During the course of the project, the temperature of the computer room climbed to nearly 104 Fahrenheit, or 40 Celsius. "We could dry the laundry immediately, but we had to pay 30,000 yen ($390) a month for electricity," Kyodo News quoted Kondo's wife, Yukiko, as saying.

Perhaps the most remarkable aspect of the news is that it took a supercomputer - the T2K-Tsukuba System - to set the previous record in 2009 of 2.5 trillion digits.

In case you were wondering what kind of configuration was required to achieve this prodigious feat, the spec sheet was a surprisingly modest one, chockablock with common off-the-shelf parts. The list included:

  • Processor: 2 x Intel Xeon X5680 @ 3.33 GHz - (12 physical cores, 24 hyperthreaded)
  • Memory: 96 GB DDR3 @ 1066 MHz - (12 x 8 GB - 6 channels)
  • Motherboard: Asus Z8PE-D12
  • Hard Drives: 1 TB SATA II (Boot drive), 5 x 2 TB SATA II (Store Pi Output), 24 x 2 TB
  • SATA II (Computation) - various models
  • Raid Controller: 3 x LSI MegaRaid SAS 9260-8i
  • Operating System: Windows Server 2008 R2 Enterprise x64