Performance improvement approach for dependable computing system with optical voting circuit

Abstract

AbstractThis paper proposes a new voting method using light that makes possible the realization of a high‐performance computing system equipped with both flexibility and dependability. Soft errors inside computers due to terrestrial radiation have become a problem in recent years. We have proposed a highly dependable triple voting‐type computing system that can be used even in the strong radiation environment of space. While this system uses reconfigurable SRAM‐based FPGA to achieve high flexibility, the system operation speed was limited by synchronization problems in voting circuits located on parallel buses, and by the bottleneck of a limited upper speed for the radiation‐tolerant device used in the voting logic circuit. As a result, we study the use of a serial bus, and propose a voting circuit using light that is suitable for a high‐speed serial bus. This optical voting circuit is highly compatible with the high‐speed serial interfaces provided on recent FPGAs, and is easily configurable using existing optical communications devices. In operations tests using an optical communications module, we obtained voting performance at a 1 Gbit/s communication speed, and estimated that the upper speed limit for the test system is 2.14 Gbit/s. Use of a higher speed optical communication module and circuit optimization should make it possible to achieve even higher speeds. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(12): 35–46, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20422