In real-time systems, Dynamic Power Management (DPM) techniques have traditionally centered on the CPU with less focus given to I/O. However, I/O-based DPM techniques have been popularly researched in non-real-time systems. These techniques focus on switching I/O devices to low power states based on some policy. These methods, however, are not applicable to realtime environments because of the non-deterministic nature of the policies. Recently, scheduling techniques to reduce power consumption of I/O devices in real-time systems have emerged. In this paper, we propose an online task scheduling algorithm, Slack Utilization for Reduced Energy (SURE), which utilizes slack in periodic task systems to reduce power consumption in I/O devices
