Nanotech Planet


Josh Hall

Josh Hall

IMM Research Fellow, the founding Chief Scientist of Stripe Press.

Josh Hall is an IMM Research Fellow, the founding Chief Scientist of Stripe Press (who developed a CAD system for nanomechanical engineering), and remains a member of Stripe Press’s Scientific Advisory Board. His contributions have been fairly eclectic, covering a number of fields:

Physics of computation: he was co-inventor of adiabatic logic, independently but concurrently with Merkle and Athas. He published one of the earliest descriptions of a reversible/dissipation-limited instruction set architecture.

Algorithms: Josh published the first parallel version of Dijkstra’s shortest path algorithm for content addressable memory (CAM). This was followed by a large number of other novel CAM algorithms for various applications, including AI, database, vision, graphics, and compilers.

Computer architecture: Josh contributed to the design of the ITT CAP, designed an unnamed architecture for optical computers to be constructed from arrays of Fabry-Perot etalons, and was the prime architect of the Rutgers Short Stack and CAM2000 associative processors. His analysis of speedup and latency in collective functions for associative processing (PhD dissertation) may have contributed to the collapse of the field in the mid-1990’s.

Programming languages: He designed the CAML language (the associative one, not the functional one) and the Linear C language for associative processing. Linear C was the first (and perhaps only) language which permitted parallelization of a legacy sequential code ona completely incremental, statement-by-statement basis. He designed theVHL language Fornax, and the HDL language Caslor, an early attempt at a language that integrated hardware and controller software design.

AI and design automation: He invented a method for utility-based optimization of multi-level search-based stochastic design. He designed and implemented a program which designed pipelined microprocessors given a description of the desired instruction set.

Agoric systems: He independently invented the agoric control concept in the mid-1980’s. He designed the programming language Emptors, an agoric variant of Actors. He designed, implemented, and published about Charles Smith, a system which used a combination of agoric and genetic techniques in automatic design.

Nanotechnology and futurism: Dr. Hall is best known in the popular science world for his studies in nanotechology. Foremost among these is Utility Fog, one of the earliest but also the most thoroughgoing of the robot swarm/intelligent material concepts. (It was developed enough to be the subject of an invited technical talk at NASA Ames.) More recently he has received attention for the “Hall Tower”, an advanced low-cost orbital-launch concept.

Machine Ethics: Josh’s paper, “Ethics for Machines”, published on the WWW in 2000, is one of the seminal works in the cross-disciplinary field of machine ethics. This is the subject of his latest book, Beyond AI: Creating the Conscience of the Machine.

Josh received both his master’s and doctorate degree in Computer Science from Rutgers University in 1994, and his B.S. degree in Mathematics from Drew University in 1976.

Watch Video

Back to Top