On toolboxes and telescopes
Abstract
We outline new ways of using computers as scientific tools, introducing two concepts which go beyond traditional numerical
simulations. On the level of software, we describe a “dynamicist’s workbench”, an environment to provide interactive support
for setting up, executing and analyzing computational experiments. On the level of hardware, we discuss the concept of a “computational
observatory”, especially designed and manufactured for specific problems in stellar dynamics.
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- The book is written to introduce all Electrical Engineering and Computer Science students to integrated system architecture and design. Combined with individual study in related research areas and participation in large system design projects, this text provides the basis for a graduate course-sequence in integrated systems. MOS devices and circuits are considered along with integrated system fabrication, data and control flow in systematic structures, the implementation of integrated system designs, the overview of an LSI computer system, the design of the OM2 data path chip, architecture and design of system controllers, the design of the OM2 controller chip, system timing, highly concurrent systems, and the physics of computational systems. Attention is given to alternative control structures, the stored-program machine, microprogrammed control, algorithms for VLSI processor arrays, and hierarchically organized machines.
- A special-purpose computer is used to integrate the orbits of the outer five planets for more than 100 Myr into the future and more than 100 Myr into the past. The strongest features in the Fourier transforms of the orbital elements of the Jovian planets can be identified with the frequencies predicted by linear secular theory. Many of the weaker features in the Fourier spectra are identified as linear combinations of the basic frequencies. Serious differences are noted between the present measurements and the predictions of Bretagnon (1974). The amplitude of the 3.796 Myr period libration of Pluto's longitude of perihelion is modulated with a period of 34 Myr. Very long periods, on the order of 137 Myr, are also seen. The orbit of Pluto is stable for the duration of the integration; the maximum Liapunov characteristic exponent is less than 10 to the -6.8 power/yr.
- We have designed and built the Orrery, a special computer for high-speed high-precision orbital mechanics computations. On the problems the Orrery was designed to solve, it achieves approximately 10 Mflops in about 1 ft3of space while consuming 150 W of power. The specialized parallelarchitecture of the Orrery, which is well matched to orbital mechanics problems, is the key to obtaining such high performance. In this paper we discuss the design, construction, and programming of the Orrery. Copyright © 1985 by The Institute of Electrical and Electronics Engineers, Inc.
