Title: Impact of Memory System Design on Communication Performance Idea: In building active message layers on a range of platforms, we find that the critical design decisions are driven by the performance of aspects of memory systems that receive very little attention in the ISCA community: cache miss penalties, uncached accesses, cache-to-cache tranfer costs, memory bus speed, and DMA. Platforms: SS 10s with L2, SS 20s w/o L2, Ultrasparc (?) Meiko slow and meiko fast Paragon Maybe sun MPs Data: Memory Hierarchy Uncached accesses Cache-to-cache latency DMA performance Analysis: Show how these impact the design and the ultimate performance of the AM layers