Supercomputer

A **supercomputer** is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second instead of million instructions per second.

Japan is the only country in the New World that has supercomputer beside normal computers like the desktop and laptop.

## Supercomputing in Japan

So far, the operational supercomputer of Japan is the **Kei Computer**. The said computer will be replaced by the **Fugaku Supercomputer** in the mid 1640's of the Central Calendar (Earth Year 2020's).

The **K computer** – named for the Japanese word/numeral "kei" (京), meaning 10 quadrillion (1016) – was a supercomputer manufactured by Fujitsu, installed at the Riken Advanced Institute for Computational Science campus in Kobe, Hyōgo Prefecture, Japan. The K computer was based on a distributed memory architecture with over 80,000 compute nodes. It was used for a variety of applications, including climate research, disaster prevention and medical research.

**Fugaku** (Japanese: 富岳) — named after an alternative name for Mount Fuji — is a petascale supercomputer at the RIKEN Center for Computational Science in Kobe, Japan. It started development in 2014 as the successor to the K computer, and it is scheduled to start operating in Earth Year 2021 (Central Calendar 1645). The Fugaku is said to be 100 times faster than the Kei.

## Specifications

### Kei Supercomputer

#### Node architecture

The K computer comprises 88,128 2.0 GHz eight-core SPARC64 VIIIfx processors contained in 864 cabinets, for a total of 705,024 cores, manufactured by Fujitsu with 45 nm CMOS technology. Each cabinet contains 96 computing nodes, in addition to six I/O nodes. Each computing node contains a single processor and 16 GB of memory. The computer's water cooling system is designed to minimize failure rate and power consumption.

#### Network

The nodes are connected by Fujitsu's proprietary torus fusion (*Tofu*) interconnect.

#### File system

The system adopts a two-level local/global file system with parallel/distributed functions, and provides users with an automatic staging function for moving files between global and local file systems. Fujitsu developed an optimized parallel file system based on Lustre, called the Fujitsu Exabyte File System (FEFS), which is scalable to several hundred petabytes.

#### Operating System

The Kei supercomputer uses the Linux as its OS.

#### Power consumption

Although the K computer reported the highest total power consumption of any 2011 TOP500 supercomputer (9.89 MW – the equivalent of almost 10,000 suburban homes), it is relatively efficient, achieving 824.6 GFlop/kW. This is 29.8% more efficient than China's NUDT TH MPP (ranked #2 in 2011), and 225.8% more efficient than Oak Ridge's Jaguar-Cray XT5-HE (ranked #3 in 2011). However, K's power efficiency still falls far short of the 2097.2 GFlops/kWatt supercomputer record set by IBM's NNSA/SC Blue Gene/Q Prototype 2. For comparison, the average power consumption of a TOP 10 system in 2011 was 4.3 MW, and the average efficiency was 463.7 GFlop/kW.

According to TOP500 compiler Jack Dongarra, professor of electrical engineering and computer science at the University of Tennessee, the K computer's performance equals "one million linked desktop computers". The computer's annual running costs are estimated at US$10 million.

### Fugaku Supercomputer

* **Location:** RIKEN Center for Computational Science (R-CCS)

* **Architecture:**
	+ 158,976 nodes
	+ Fujitsu A64FX CPU (48+4 core) per node
	+ Tofu interconnect D

* **Operating system:** Custom Linux-based kernel
* **Memory:** HBM2 32 GiB/node
* **Storage:**
	+ 1.6 TB NVMe SSD/16 nodes (L1)
	+ 150 PB Shared Lustre FS (L2)
	+ Cloud storage services (L3)

* **Speed:** 415 PFLOPS (per TOP500 Rmax)

## Chronology

During the conversation between King Bank of Riem Kingdom and his prime minister, the latter mentioned about the Kei supercomputer to the former which astound him since it can performed 10 quadrillion calculations per second.

During the visit of Holy Mirishial Empire diplomat team, HME diplomat Phiam showed off the empire's desktop-sized magical calculator to Japanese diplomat Kondo to regain some sense of technological pride, assuming that Japan didn't have calculator like theirs. However, their effort was completely futile as Kondo not only revealed the existing of the cheap and pocket-sized conventional calculators but also the calculator app in his smartphone. To put the final nail in the arrogance of the Holy Mirishial Empire, Kondo revealed that Japan possesses a Supercomputer that can calculate quadrillion of calculations in a mere second. All these fact made all HME diplomat sulked in defeat and deep shame.