Network Systems Colloquium

EMERALDS: A Small-Memory Real-Time Microkernel

Prof. Kang G. Shin
University of Michigan

October 5, 11AM
*Note special date and time*
CS 111


EMERALDS (Extensible Microkernel for Embedded, ReAL-time, Distributed Systems) is a real-time microkernel designed for small-memory embedded applications. These applications must run on slow (15--25MHz) processors with just 32--128~kbytes of memory, either to keep production costs down in mass-produced systems or to keep weight and power consumption low. To be feasible for such applications, the OS must not only be small in size (less than 20 kbytes) but also have low-overhead kernel services. Unlike commercial embedded OSs which rely on carefully-optimized code to achieve efficiency, EMERALDS takes the approach of re-designing the basic OS services of task scheduling, synchronization, communication, and system call mechanism by using characteristics found in small-memory embedded systems such as small code size and a priori knowledge of task execution & communication patterns. With these new schemes, the overheads of various OS services are reduced 20--40% without compromising any OS functionality.

This work is done jointly with Khawar M. Zuberi and Babu Pillai.

Dr. Kang G. Shin is Professor of Computer Science and Engineering, and the Founding Director of the Real-Time Computing Laboratory (RTCL) in the Electrical Engineering and Computer Science Department at the University of Michigan. A short biographical sketch can be found at

The Network Systems Colloquium is sponsored by the Network Systems Lab at Purdue University. For further information, please contact Kihong Park ( or 765-494-7821).