User: sidles

Space bridge -- physics dream, engineer nightmare

On: Notes From 3rd Annual Space Elevator Conference

Consider the ultimate composite nanotube material -- stiffness 10^12 Pascal, yield strength 10^10 Pascal. So at-yield, it stretches 10%. The stored elastic energy density then is 5x10^9 J/m^3. This is roughly the same stored energy as an equal volume of TNT (4.1x10^9 J/ton)! Yikes! You can think of the deployed nanotube bridge as a gigantic PrimaCord detonating system.

Donald Knuth on patents

On: Apple Tries to Patent iPod User Interface

Since 1994, Donald Knuth has lobbied against algorithm patents. Perhaps we ought to ask whether interface patents are not just as destructive of freedom and human rights.

Do interface patents "take away [our] right to use fundamental building blocks" (in Knuth's words)?

Here is the text of Knuth's letter.

Commissioner of Patents and Trademarks
Box 4, Patent and Trademark Office
Washington, DC 20231

February 1994

Dear Commissioner:

Along with many other computer scientists, I would like to ask you to reconsider the current policy of giving patents for computational processes. I find a considerable anxiety throughout the community of practicing computer scientists that decisions by the patent courts and the Patent and Trademark Office are making life much more difficult for programmers.

In the period 1945-1980, it was generally believed that patent law did not pertain to software. However, it now appears that some people have received patents for algorithms of practical importance--e.g., Lempel-Ziv compression and RSA public key encryption--and are now legally preventing other programmers from using these algorithms.

This is a serious change from the previous policy under which the computer revolution became possible, and I fear this change will be harmful for society. It certainly would have had a profoundly negative effect on my own work: For example, I developed software called TeX that is now used to produce more than 90% of all books and journals in mathematics and physics and to produce hundreds of thousands of technical reports in all scientific disciplines. If software patents had been commonplace in 1980, I would not have been able to create such a system, nor would I probably have ever thought of doing it, nor can I imagine anyone else doing so.

I am told that the courts are trying to make a distinction between mathematical algorithms and nonmathematical algorithms. To a computer scientist, this makes no sense, because every algorithm is as mathematical as anything could be. An algorithm is an abstract concept unrelated to physical laws of the universe.

Nor is it possible to distinguish between "numerical" and "nonnumerical" algorithms, as if numbers were somehow different from other kinds of precise information. All data are numbers, and all numbers are data. Mathematicians work much more with symbolic entities than with numbers.

Therefore the idea of passing laws that say some kinds of algorithms belong to mathematics and some do not strikes me as absurd as the 19th century attempts of the Indiana legislature to pass a law that the ratio of a circle's circumference to its diameter is exactly 3, not approximately 3.1416. It's like the medieval church ruling that the sun revolves about the earth. Man-made laws can be significantly helpful but not when they contradict fundamental truths.

Congress wisely decided long ago that mathematical things cannot be patented. Surely nobody could apply mathematics if it were necessary to pay a license fee whenever the theorem of Pythagoras is employed. The basic algorithmic ideas that people are now rushing to patent are so fundamental, the result threatens to be like what would happen if we allowed authors to have patents on individual words and concepts. Novelists or journalists would be unable to write stories unless their publishers had permission from the owners of the words. Algorithms are exactly as basic to software as words are to writers, because they are the fundamental building blocks needed to make interesting products. What would happen if individual lawyers could patent their methods of defense, or if Supreme Court justices could patent their precedents?

I realize that the patent courts try their best to serve society when they formulate patent law. The Patent Office has fulfilled this mission admirably with respect to aspects of technology that

Von Neumann's Voice

On: Happy Birthday, Von Neumann (And Linus!)

Here is a poignant recording of von Neumann's voice:

"Those of you present who have lived with this field, and who have lived with and suffered with computing machines of various sorts, and know what kind of regime it is to invest in one, I'm sure have appreciated the fact that it appears that this machine has been completely assembled less than two months ago, has been run on problems less than two weeks ago, and yesterday already ran for four hours without making a mistake! Those of you who have *not* been exposed to computing machines, and who do not have the desolate feeling which goes with living with their mistakes, will appreciate what it means that a computing machine, after about two weeks of breaking in, has really a faultless run of four hours. It is completely fantastic on an object of this size; I doubt it has ever been achieved before, and it is an enormous reassurance regarding the state of the art and regarding the complexities to which one will be able to go in the future, that this has been achieved."