Kazutomo Yoshii is principal software development specialist in the Mathematics and Computer Science division at Argonne National Laboratory. He received his M.S. in computer science from Toyohashi University of Technology in Japan in 1994. After ten year's experience in industry, he joined Argonne National Laboratory in 2004. He was the lead developer of the ZeptoOS project, which is a DOE funded research project studying operating systems for petascale architectures with 10,000 to 1 million CPUs. He successfully designed and developed "Big Memory", an alternative, transparent memory space that successfully removes the memory performance bottleneck on Blue Gene/P Linux. His "Big Memory" implementation also enabled online central processing for the LOw Frequency ARay (LOFAR) radio telescope. He also developed driver codes or libraries for monitoring and controlling hardware, including a power reading code for BlueGene/Q. Towards the post-Moore era, he is now exploring reconfigurable computing, in particular FPGAs, for next-generation supercomputers.