System-Management-Mode in Real-Time PC-Based Control Applications

Abstract

There is a tendency toward the use of personal computers in real-time control applications. These computers have high processing capacity and reduced costs when compared to software and hardware development for dedicated platforms. However, some control systems require latency predictability and the processors of the x86 architecture have a special protection and correction mode known as system management mode (SMM). This mode is not traceable by the operating system, and it can cause unpredictability in the system. This article describes the SMM, presents tools and methods for its detection and an analysis of its impact on real-time systems.