Swiss uni takes the world record after 108 days and 9 hours of divisive effort

Switzerland's University of Applied Sciences Graubünden has claimed the world record for calculating Pi, which it says it has computed to 62.8 trillion digits.

The university yesterday claimed the record, asserting that it beat previous attempts by 12.8 trillion digits, and did it 3.5 times faster than previous attempts at calculating the irrational ratio.

Helpfully, the uni has also published details of the hardware used for its feat.

A pair of 32-core AMD Epyc 7542 processors powered the uni's rig. AMD states the CPU cores spend most of their time at 2.9GHz, can burst to 3.4GHz, have 128MB L3 cache and happily run 64 threads apiece. A server with 1TB of RAM was also employed, with Ubuntu 20.04 installed on a pair of solid-state disks of unspecified size.

A JBOD housed 38 7200RPM hard disks, each with 16TB capacity.

Thirty-four of those disks were used to store values swapped from RAM – a design chosen because memory is very expensive. Hard disks were chosen over SSDs because SSD performance degrades over time and the university's designers feared their intensive calculations could cause problems. 

The uni's rig was modest compared to the cloudy 96-vCPU effort that Google employed to calculate Pi to 31.4 trillion decimal places back in 2019.

An app called y-Cruncher did the work, and was configured to move data in parallel from the server to the 34 disks at around 8.5GB/sec.

Sharp-eyed readers will have noted that the JBOD housed 38 disks – the other four were used to store the value of Pi itself.

The last ten digits stored on those disks are 7817924264 and they are now the last known digits of Pi. ®

https://www.theregister.com/2021/08/17/pi_world_record/