Abstract: Moore’s Law, doubling the number of transistors in a chip every two years, has so far contributed to the evolution of computer systems. Unfortunately, we cannot expect sustainable transistor shrinking anymore, marking the beginning of the so-called post-Moore era. Therefore, it has become essential to explore emerging devices, and superconductor single-flux-quantum (SFQ) logic that operates in a 4.2-kelvin environment is a promising candidate. Josephson junctions (JJs) are used as switching elements in SFQ logic to compose a superconductor ring (SFQ ring) that can store (or trap) and transfer a single magnetic flux quantum. It fundamentally operates with the voltage pulse-driven nature that makes it possible to achieve extremely low-latency and low-energy JJ switching. This talk shares the history of our SFQ Research, e.g., revisiting microarchitecture and demonstrating over 30 GHz microprocessor and AI accelerator designs. Then, the role of computer architecture for such emerging device computing is discussed.

Bio: Koji Inoue is a professor of Department of Advanced Information Technology at Kyushu University, Japan. His current broader research interests are in computer architecture, IoT platform, and cyber-physical systems. Currently his driving researches target emerging devices for superconductor computing, nanophotonic computing, and quantum computing. He served as a general chair of many conferences, including the IEEE/ACM International Symposium on Microarchitecture (MICRO) 2018, the International Forum on Embedded MPSoC and Multicore (MPSoC) 2011, and the International Symposium on Low Power Electronics and Design (ISLPED) 2011. He received his PhD in Computer Science and Communication Engineering from Kyushu University in 2001. He also joined Halo LSI Design & Technology, Inc., NY, as a circuit designer in 1999.