This paper discusses the use of software methods to collect system trace for DEC Ultrix and 3.0 Mach on a DECstation 5000/200. We assert that software methods are a valuable tool for collecting system trace and understanding operating system and memory system behavior for modern workstation workloads. Software methods have some well documented shortcomings. We discuss how their impact was minimized in our system. We further support the validity of the software support approach by comparing behavior predicted by our tracing/simulation system to measurements made with less intrusive methods.