Software methods for system address tracing

interpreted as representing the official policies, either expressed or implied, of Digital Equipment Corporation or the U.S. Government. This paper discusses the use of software methods to collect system trace for DEC Ultrix and 3.0 Mach on a DECstation 5000/260. We assert that software methods are a valuable tool for collect-ing system trace and understanding operating system and memory system behavior for modem workstation workloads. Software methods have some well documented shortcomings. We dis-cuss how their impact was minimized in our system. We further support the validity of the software approach by comparing behavior predicted by our tracing/simulation system to measure-ments made with less intrusive methods. Aeoassjon For IR