Amorphous Computing 1

Amorphous computing is the development of organizational principles and programming languages for obtaining coherent behavior from the cooperation of myriads of unreliable parts that are interconnected in unknown, irregular, and time-varying ways. The impetus for amorphous computing comes from developments in microfabrication and fundamental biology, each of which is the basis of a kernel technology that makes it possible to build or grow huge numbers of almost-identical information-processing units at almost no cost. This paper sets out a research agenda for realizing the potential of amorphous computing and surveys some initial progress, both in programming and in fabrication. We describe some approaches to programming amorphous systems, which are inspired by metaphors from biology and physics. We also present the basic ideas of cellular computing, an approach to constructing digital-logic circuits within living cells by representing logic levels by concentrations DNA-binding proteins. Over the next few decades, two emerging technologies|microfabrication and cellular engineering|will make it possible to assemble systems that incorporate myriads of information-processing units at almost no cost, provided: 1) that all the units need not work correctly; and 2) that there is no need to manufacture precise geometrical arrangements of the units or precise interconnections among them. This technology shift will precipitate fundamental changes in methods for constructing and programming computers, and in the view of computation itself. Microelectronic mechanical components are becoming so inexpensive to manufacture that we can anticipate combining logic circuits, microsensors, actuators, and communications devices integrated on the same chip to produce particles that could be mixed with bulk materials, such as paints, gels, and concrete. Imagine coating bridges or buildings with smart paint that can sense and report on traÆc and wind loads and monitor structural integrity of the bridge. A smart-paint coating on a wall could sense vibrations, monitor the premises for intruders, or cancel noise. Even more striking, there has been such astounding progress in understanding the biochemical mechanisms in individual cells, that it appears we'll be able to harness these mechanisms to construct digital-logic circuits. Imagine a discipline of cellular engineering This report describes research done at the Arti cial Intelligence Laboratory of the Massachusetts Institute of Technology. Support for this research is provided in part by the Advanced Research Projects Agency of the Department of Defense under OÆce of Naval Research contract N00014-96-1-1228.