The semantics of memory-a large state which can only be read or changed a small piece at a time-has remained virtually untouched since von Neumann, and its effects-latency and bandwidth-have proved to be the major stumbling block for high performance computing. This paper suggests a new model, termed “microservers,” that exploits “Processing-In- Memory” VLSI technology, and that can reduce latency and memory traffic, increase inherent opportunities for concurrency, and support a variety of highly concurrent programming paradigms. Application of this model is then discussed in the framework of several on-going supercomputing programs, particularly the HTMT petaflops project