I found this recently published book absolutely riveting. It is destined to change the very basis of digital systems design and potentially the basis of programming and software engineering as well. Its author, Karl Fant, is the principal of Theseus Research http://www.theseusresearch.com/ and founder of spin-off company Theseus Logic http://www.theseus.com/.



He holds 29 patents in various aspects of digital design and is, without doubt, one of the most profound thinkers on the fundamentals of digital design and computer science. On his website there are a number of papers challenging the very basis of computer science http://www.theseusresearch.com/invocation model.htm



He challenges many accepted "obvious" truths. According to Karl:



* "Boolean logic" is expressively incomplete as the basis for circuit design as it requires some other means for expressing the timing relationships needed to guarantee correct computing results. He replaces Boolean logic with his 2 state Null Convention Logic (2NCL) with amazing results.

* Concurrency is the most basic and most general model of computing, with sequential processing as a special case.

* Computer science as the science and theory of process expression rather than the science of algorithms.

* Replacing the notion of variable and thereby eliminating a large number of logical and expressive problems.



This work is immensely practical. A logically and expressively complete method for designing asynchronous circuits should result in circuits and chips that are faster; consume less power; make better use of use on-chip real estate; and produce less radio interference.



The potential to specify software fully without the need to deal separately with timing issues is very exciting indeed.



For the past 40 odd years most computers and computer-based devices have been designed as clock-driven or synchronous devices. This was not always so. The early computers such as the ENIAC and UNIVAC were asynchronous, largely because clocked synchronicity had not yet been fully figured out.



In the early 50s and 60s there were several University-based research projects to develop explicitly architectures including the University of Manchester (UK) MU5 project (www.computer50.org/kgill/mu5/mu5.html) and the University of Illinois ILLIAC I and ILLIAC II computer series (See the book "Asynchronous System Design by Chris J Myers 2001, John Wiley and Sons, Inc and http://www.async.ece.utah.edu/). One of the last commercially viable fully asynchronous computers was the first PDP-10 (Digital Equipment), the KA 10 designed by a team led by Alan Kotok.



There are currently a number of asynchronous design research projects in Universities and industry. Ivan Sutherland and Jo Ebergen of SUN summarised a lot of the current work in Computers Without Clocks, Scientific American, 15 July 2002.



What Mr. Fant has done that is unique is provide a solid universal logical theory that, for the first time encompasses all of the known special cases and much more besides.