The K-computer, developed by RIKEN and Fujitsu, was a groundbreaking supercomputer that held the title of the world’s fastest from 2011 to 2013. Representing a significant leap in Japanese technological prowess, it was designed to tackle complex scientific problems, particularly in areas like climate modeling, drug discovery, and materials science. Its architecture, based on the SPARC64 VIIIfx processor, was unique and aimed to achieve high performance with energy efficiency. The K-computer’s development and operation provide valuable insights into the challenges and opportunities in the field of high-performance computing. Development and Architecture The K-computer project began in 2009 with a budget of ¥110 billion (approximately $1.1 billion USD at the time). RIKEN, Japan’s largest comprehensive research institution, partnered with Fujitsu to design and build the system. The name "K" stands for "Kei," the Japanese word for 10 quadrillion, representing the computer’s target processing capability of 10 petaflops. Its architecture was radically different from many contemporary supercomputers. It utilized over 88,000 SPARC64 VIIIfx processors, each with eight cores, resulting in a total of 709,024 cores. These processors were interconnected using a 6-dimensional torus network, a complex arrangement designed to minimize communication latency. The system consumed approximately 12.66 megawatts of power. Key Specifications and Performance Here's a breakdown of the K-computer’s key specifications: Specification Value Peak Performance 11.28 petaflops Sustained Performance 10.51 petaflops Number of Processors 88,128 Number of Cores 709,024 Memory 1.4 petabytes Power Consumption 12.66 MW Scientific Achievements The K-computer was utilized for a wide range of scientific simulations and research projects. Some notable achievements include: Climate Modeling: It was used to create highly detailed climate models, improving our understanding of global warming and its potential impacts. Simulations included detailed analysis of rainfall patterns and ocean currents. Drug Discovery: The K-computer aided in the development of new drugs by simulating molecular interactions and identifying potential drug candidates. Materials Science: Researchers used the K-computer to simulate the properties of new materials, accelerating the discovery of materials with specific characteristics. Astrophysics: Simulations of galaxy formation and evolution were conducted, providing insights into the universe's structure. Seismic Analysis: The K-computer was used to model earthquake phenomena, improving our ability to predict and mitigate seismic risks. Challenges and Limitations Despite its impressive performance, the K-computer faced several challenges. Its complex architecture made programming and optimization difficult. The high power consumption also posed a significant operational cost. Furthermore, the SPARC64 architecture was less common than x86, limiting the availability of software and expertise. Decommissioning and Legacy In August 2019, the K-computer was officially decommissioned. By this time, it had been surpassed by more powerful supercomputers, including those utilizing x86 processors and GPU acceleration. Its successor, Fugaku, also developed by RIKEN and Fujitsu, took its place as the world’s fastest supercomputer in 2020. The K-computer’s legacy lies in its pioneering architecture and its contribution to scientific advancements. It paved the way for Fugaku and continues to influence the design of future supercomputers. The K-computer represented a pivotal moment in the history of supercomputing, showcasing Japan’s commitment to technological innovation. While it faced challenges related to programming complexity and power consumption, its contributions to climate modeling, drug discovery, and materials science were substantial. Its decommissioning marked the end of an era, but its legacy continues to inspire the development of even more powerful and efficient supercomputers like Fugaku, pushing the boundaries of scientific exploration and technological progress.

Question 42 | UPSC Mains GENERAL-STUDIES-PAPER-II 2011

K-computer

How to Approach

This question requires a comprehensive understanding of the K-computer, its significance, and its place within the broader context of supercomputing. The answer should cover its technical specifications, development history, achievements, and eventual successor. Structure the answer chronologically, starting with its inception, detailing its capabilities, and concluding with its legacy and the current state of supercomputing. Focus on its impact on scientific research and technological advancement.

Development and Architecture

The K-computer project began in 2009 with a budget of ¥110 billion (approximately $1.1 billion USD at the time). RIKEN, Japan’s largest comprehensive research institution, partnered with Fujitsu to design and build the system. The name "K" stands for "Kei," the Japanese word for 10 quadrillion, representing the computer’s target processing capability of 10 petaflops.

Its architecture was radically different from many contemporary supercomputers. It utilized over 88,000 SPARC64 VIIIfx processors, each with eight cores, resulting in a total of 709,024 cores. These processors were interconnected using a 6-dimensional torus network, a complex arrangement designed to minimize communication latency. The system consumed approximately 12.66 megawatts of power.

Key Specifications and Performance

Here's a breakdown of the K-computer’s key specifications:

Specification	Value
Peak Performance	11.28 petaflops
Sustained Performance	10.51 petaflops
Number of Processors	88,128
Number of Cores	709,024
Memory	1.4 petabytes
Power Consumption	12.66 MW

Scientific Achievements

The K-computer was utilized for a wide range of scientific simulations and research projects. Some notable achievements include:

Climate Modeling: It was used to create highly detailed climate models, improving our understanding of global warming and its potential impacts. Simulations included detailed analysis of rainfall patterns and ocean currents.
Drug Discovery: The K-computer aided in the development of new drugs by simulating molecular interactions and identifying potential drug candidates.
Materials Science: Researchers used the K-computer to simulate the properties of new materials, accelerating the discovery of materials with specific characteristics.
Astrophysics: Simulations of galaxy formation and evolution were conducted, providing insights into the universe's structure.
Seismic Analysis: The K-computer was used to model earthquake phenomena, improving our ability to predict and mitigate seismic risks.

Challenges and Limitations

Despite its impressive performance, the K-computer faced several challenges. Its complex architecture made programming and optimization difficult. The high power consumption also posed a significant operational cost. Furthermore, the SPARC64 architecture was less common than x86, limiting the availability of software and expertise.

Decommissioning and Legacy

In August 2019, the K-computer was officially decommissioned. By this time, it had been surpassed by more powerful supercomputers, including those utilizing x86 processors and GPU acceleration. Its successor, Fugaku, also developed by RIKEN and Fujitsu, took its place as the world’s fastest supercomputer in 2020. The K-computer’s legacy lies in its pioneering architecture and its contribution to scientific advancements. It paved the way for Fugaku and continues to influence the design of future supercomputers.

Additional Resources

Key Definitions

Petaflop

A petaflop is a measure of a computer’s performance, equal to one quadrillion (10<sup>15</sup>) floating-point operations per second.

Toroidal Network

A toroidal network is a type of interconnection network used in parallel computing systems. It arranges processors in a grid-like structure where the edges wrap around to form a torus (donut shape), minimizing communication distances and improving performance.

Key Statistics

The K-computer consumed approximately 12.66 megawatts of power, equivalent to the electricity consumption of approximately 9,900 Japanese households (as of 2011).

Source: RIKEN

The K-computer had 709,024 processor cores, making it one of the most massively parallel computers of its time.

Source: Top500 list (knowledge cutoff 2023)

Examples

Fugaku Supercomputer

Fugaku, the successor to the K-computer, utilizes the ARM-based A64FX processor and achieved a HPL (High-Performance Linpack) score of 442.01 petaflops in June 2020, making it the world’s fastest supercomputer at the time.

Frequently Asked Questions

▶Why was the K-computer decommissioned?

The K-computer was decommissioned because newer supercomputers, such as Fugaku, surpassed its performance and energy efficiency. Maintaining and operating the K-computer became increasingly costly compared to the benefits it provided.