A Preliminary Report on the Caltech ARPA Tester Project

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Taking ASCI Supercomputing to the End Game

The ASCI supercomputing program is broadly defined as running physics simulations on progressively more powerful digital computers. What happens if we extrapolate the computer technology to its end? We have developed a model for key ASCI computations running on a hypothetical computer whose technology is parameterized in ways that account for advancing technology. This model includes technology information such as Moore’s Law for transistor scaling and developments in cooling technology. The model also includes limits imposed by laws of physics, such as thermodynamic limits on power dissipation, limits on cooling, and the limitation of signal propagation velocity to the speed of light. We apply this model and show that ASCI computations will advance smoothly for another 10-20 years to an “end game ” defined by thermodynamic limits and the speed of light. Performance levels at the end game will vary greatly by specific problem, but will be in the Exaflops to Zettaflops range for currently anticipate

Testing and Structured Design

This paper describes part of an integrated circuit testing project carried out at Caltech between 1979 and 1982. The central theme and result of the project is a language or notation for describing tests for complex integrated circuits. The evolution of this test language has been guided by many considerations, including (1) its implementation in a working, interactive test system called FIFI, (2) its fit to ideas about the architecture of high-performance test instruments, and (3) its expressivity for a design-for-testability strategy for chip designs structured in the general style presented by Mead and Conway [1]

Thermodynamic Computing

The hardware and software foundations laid in the first half of the 20th Century enabled the computing technologies that have transformed the world, but these foundations are now under siege. The current computing paradigm, which is the foundation of much of the current standards of living that we now enjoy, faces fundamental limitations that are evident from several perspectives. In terms of hardware, devices have become so small that we are struggling to eliminate the effects of thermodynamic fluctuations, which are unavoidable at the nanometer scale. In terms of software, our ability to imagine and program effective computational abstractions and implementations are clearly challenged in complex domains. In terms of systems, currently five percent of the power generated in the US is used to run computing systems - this astonishing figure is neither ecologically sustainable nor economically scalable. Economically, the cost of building next-generation semiconductor fabrication plants has soared past $10 billion. All of these difficulties - device scaling, software complexity, adaptability, energy consumption, and fabrication economics - indicate that the current computing paradigm has matured and that continued improvements along this path will be limited. If technological progress is to continue and corresponding social and economic benefits are to continue to accrue, computing must become much more capable, energy efficient, and affordable. We propose that progress in computing can continue under a united, physically grounded, computational paradigm centered on thermodynamics. Herein we propose a research agenda to extend these thermodynamic foundations into complex, non-equilibrium, self-organizing systems and apply them holistically to future computing systems that will harness nature's innate computational capacity. We call this type of computing "Thermodynamic Computing" or TC.Comment: A Computing Community Consortium (CCC) workshop report, 36 page

Techniques for Testing Integrated Circuits

A language is presented for describing tests of integrated circuits. The language has a high abstractive capability that enables test specifications to follow the structural or logical organization of a design. The test language is applied to a number of current design styles in a series of examples. Methods for designing integrated circuits for testability are demonstrated. An implementation of the test language through a test language interpreter and a tester is discussed. Tester designs are presented that will execute the test language with unusually high efficiency.</p

Reversible L ogic for Supercomputing

This paper is ab out making reversib le logic a reali ty for supercomputing. Reversib le logic offers a way to ex ceed certain b asic limits on the performance of computers, yet a powerful case will have tob e made to justify its sub stantial dev elopment expense. This paper explores the limits of current, irreversib le logic for supercomputers, thus forming a threshold ab ove which reversib le logic is the only solution. Prob lems ab o ve this threshold are discussed, with the science and mitig ation of glob al warmingb eing discussed in detail. To further devel op the idea of using reversib le logic in supercomputing, a design for a 1 Zettaflops supercomputer as required for addressing glob al climate warming is presented. However, to create su ch a design requires deviations from the mainstream ofb oth the software for climate simulation and research directions of rever sib le logic. These deviations provide direction on how to make r eversib le logic practical