The world’s most powerful supercomputers use Linux. Everyone has heard something about supercomputers. What is a supercomputer? A device whose computing capabilities are by far higher than those of common computers. The most powerful supercomputer nowadays exceeds 440 Petaflops (PFlops). This is a performance no personal device can achieve. Since the end of 2009, Linux has dominated the list of the world’s 500 most powerful supercomputers.
Linux: more than 20 years in the supercomputing world
The TOP500 list has been updated twice a year (in June and November) since 1993. Linux appeared for the first time in this list of the world’s most powerful supercomputers in June 1998. The first supercomputer using Linux to be included in the list was the Avalon Cluster from the United States, in the 314th position. The Avalon Cluster supercomputer had 140 Alpha EV56 processors.
In the nineties, commercial versions of Unix such as IRIX, UNICOS, AIX or Solaris dominated the TOP500 list. Besides, at that point, Windows and MacOS were already focused on end user devices. But, from 1998 onwards, the evolution of Linux was outstanding in the supercomputing field. Throughout the years, Linux’s growth has been unstoppable; specially between November 2002 and November 2009. During that 7-year period, Linux went from being used in 71 supercomputers to being used in 448 supercomputers.
Currently, Linux is the clear leader in supercomputing. For Linux to lose the leadership, a big hardware revolution should take place. However, as time goes by, we will see if other alternatives emerge to challenge Linux’s leadership.
Why is Linux perfect for supercomputers?
There are many reasons why most supercomputers have chosen Linux. Let’s see some of the main reasons why Linux is the leader in supercomputing:
- Open operating system. Since it is an open source system, it is 100% customizable. This feature enables the free modification of any part of the code. It is useful both for improving performance and solving any security problem.
- Lower consumption of resources. As it is customizable, performance can be boosted by specifying that only vital applications are executed. This cannot be done with other operating systems, since they do not usually allow specific configurations.
- Modular structure. This is one of the most important features of Linux. As it is completely open, new modules can be added without affecting other parts within the operating system. Besides, resource optimization is much easier.
- Adapted to all kinds of workloads. Its ability to adapt to all kinds of workloads is a very important feature as well. This makes measuring the supercomputer efficiency, consumption and performance easier.
- Costs. As it is completely free, there is no need to pay for a license to use it. So, the necessary investment is the time required to modify the OS for each project.
The world’s 10 most powerful supercomputers
These are the ten most powerful supercomputers in the world, according to the TOP500 list (November 2021 update).
| Supercomputer | Country | OS | Rmax | Rpeak |
| #1 Supercomputer Fugaku | Japan | Red Hat Enterprise Linux | 442,010 TFlops | 537,212 TFlops |
| #2 Summit | United States | RHEL 7.4 | 148,600 TFlops | 200,795 TFlops |
| #3 Sierra | United States | Red Hat Enterprise Linux | 94,640 TFlops | 125,712 TFlops |
| #4 Sunway TaihuLight | China | Sunway RaiseOS 2.0.5 | 93,014.6 TFlops | 125,436 TFlops |
| #5 Perlmutter | United States | HPE Cray OS | 70,870 TFlops | 93,750 TFlops |
| #6 Selene | United States | Ubuntu 20.04.1 LTS | 63,460 TFlops | 79,215 TFlops |
| #7 Tianhe-2A | China | Kylin Linux | 61,444.5 TFlops | 100,679 TFlops |
| #8 JUWELS Booster Module | Germany | CentOS | 44,120 TFlops | 70,980 TFlops |
| #9 HPC5 | Italy | CentOS Linux 7 | 35,450 TFlops | 51,720.8 TFlops |
| #10 Voyager-EUS2 | United States | Ubuntu 18.04 LTS | 30,050 TFlops | 39,531.2 TFlops |
Evolution of the Top 3 supercomputers since 2010
The following table compiles those supercomputers that have been in the top 3 positions of the TOP500 list from 2010 to 2021.
| Top 1 | Top 2 | Top 3 | |
| June 2010 | Jaguar (United States) | Nebulae (China) | Roadrunner (United States) |
| November 2010 | Tianhe-1A (China) | Jaguar (United States) | Nebulae (China) |
| June/November 2011 | K computer (Japan) | Tianhe-1A (China) | Jaguar (United States) |
| June 2012 | Sequoia (United States) | K computer (Japan) | Mira (United States) |
| November 2012 | Titan (United States) | Sequoia (United States) | K computer (Japan) |
| June/November 2013 | Tianhe-2A (China) | Titan (United States) | Sequoia (United States) |
| June 2014 | Tianhe-2A (China) | Titan (United States) | Sequoia (United States) |
| June/November 2015 | Tianhe-2A (China) | Titan (United States) | Sequoia (United States) |
| June/November 2016 | Sunway TaihuLight (China) | Tianhe-2A (China) | Titan (United States) |
| June/November 2017 | Sunway TaihuLight (China) | Tianhe-2A (China) | Piz Daint (Switzerland) |
| June 2018 | Summit (United States) | Sunway TaihuLight (China) | Sierra (United States) |
| November 2018 | Summit (United States) | Sierra (United States) | Sunway TaihuLight (China) |
| June/November 2019 | Summit (United States) | Sierra (United States) | Sunway TaihuLight (China) |
| June 2020 | Supercomputer Fugaku (Japan) | Summit (United States) | Sierra (United States) |
| November 2020 | Supercomputer Fugaku (Japan) | Summit (United States) | Sierra (United States) |
| June 2021 | Supercomputer Fugaku (Japan) | Summit (United States) | Sierra (United States) |
| November 2021 | Supercomputer Fugaku (Japan) | Summit (United States) | Sierra (United States) |
List of supercomputers which have ever been in the first position
Here is a list of the supercomputers that have held the first position in the TOP500 list since 1993.
- CM-5/1024 (United States)
- Numerical Wind Tunnel (Japan)
- XP/S140 (United States)
- SR2201/1024 (Japan)
- CP-PACS/2048 (Japan)
- ASCI Red (United States)
- ASCI White, SP Power3 375 MHz (United States)
- Earth-Simulator (Japan)
- BlueGene/L beta-System (United States)
- BlueGene/L – eServer Blue Gene Solution (United States)
- Roadrunner (United States)
- Jaguar (United States)
- Tianhe-1A (China)
- K computer (Japan)
- Sequoia (United States)
- Titan (United States)
- Tianhe-2A (China)
- Sunway TaihuLight (China)
- Summit (United States)
- Supercomputer Fugaku (Japan)
Supercomputers by continent
This is the distribution of the most powerful supercomputers in the TOP500 list by continent, as of November 2021:
- Asia: 226 supercomputers.
- North America: 160 supercomputers.
- Europe: 105 supercomputers.
- South America: 5 supercomputers.
- Oceania: 3 supercomputers.
- Africa: 1 supercomputer.
China: the leader in number of supercomputers
Since November 2017, China has been the leader in the number of supercomputers. As of November 2021, China has 173 supercomputers among the world’s 500 most powerful supercomputers. It is followed by the United States, with 149 supercomputers, and Japan, with 32 supercomputers. Nevertheless, regarding performance, the United States is the leader with a Rmax of 986,467,180 Gigaflops (GFlops). Rmax is the acronym for “Maximal LINPACK performance achieved”. It is followed by Japan, with a Rmax of 628,248,000 GFlops, and China, with a Rmax of 530,072,392 GFlops.
