Alan Turing Centenary, Part 3

June 25, 2012

I’ve come across a few more items of interest in connection with the Alan Turing Centenary.  The Official Google Blog has a post marking Turing’s 100th birthday, last Saturday, June 23. In addition to discussing some of Turing’s work, it describes Google’s involvement in the Bletchley Park restoration project, and gives a brief overview of the recently-opened Turing exhibit at the Science Museum.

Google also had a home page “doodle” in honor of Turing’s birthday, which was a small, working Turing machine.  You  can play with it here.

The BBC News site has added a couple of additional essays about Turing.  The first of these includes reminiscences of Turing from two of colleagues.  One, Mike Woodger, served as Turing’s assistant at the National Physical Laboratory after WW II.

Mike Woodger worked as an assistant to Alan Turing in 1946 – the year Turing, fresh from his wartime work code-breaking, joined the National Physical Laboratory, in Teddington. Turing left after a year, but Mr Woodger stayed on to work on the completion of the Pilot Ace Computer, which Turing had helped to design.

The other colleague was Captain Jerry Roberts, a linguist and code-breaker at Bletchley Park from 1941 to 1945.  He remembers the huge importance of Turing’s breaking the German naval Enigma.

Up to the time when he broke it, Britain had been losing tremendous tonnages of shipping, including all our food imports.

If we had gone on losing the same amount of shipping, in another four to six months Britain would have lost the war.

The next BBC essay is by the scriptwriter, Graham Moore, who reviews some of Turing’s appearances in fiction and biography.

If Alan Turing had not existed, would we have had to invent him? The question seems to answer itself: Alan Turing very much did exist, and yet we have persisted in inventing him still.

He mentions the 1986 play, Breaking the Code, by Hugh Whitemore.  I had a chance to see this during its run on Broadway, with Derek Jacobi playing the role of Turing, and enjoyed it very much.  Apparently the BBC has also made a film version. In a slightly different vein, there is Neal Stephenson’s novel, Cryptonomicon.

Stephenson uses historical fiction’s ability to conjure hypothetical, counterfactual realities to play a great game of “what if” with the Turing legend.

I’ve read Cryptonomicon, and recommend it highly.  I’m not familiar with the other works Moore mentions, but they’re now on my list to look into.

Finally, for those readers who may have a DIY itch that needs scratching, it is possible to build a Turing machine out of LEGOs.

In honor of Alan Turing’s hundredth birthday, Davy Landman, Jereon van den Bos, and Paul Klint built a Turing Machine out of LEGOs. And if you like, you can build one too.

Please enjoy!


Turing Exhibit Opens at Science Museum

June 24, 2012

As part of the Alan Turing Centenary, the Science Museum in London has opened a new exhibit on Turing’s life and work.  The exhibit includes a number of items related to Turing, including a model of the Pilot ACE computer, for which Turing produced the basic design in 1945 at the National Physical Laboratory, and an example of a German Enigma cipher machine.

The “Babbage” blog at The Economist has a review of the exhibit, and the ways in which it relates to Turing’s life, in an attempt to give a rounded picture of the man.

Unlike other Turing tributes, which have tended to focus on one aspect of his work, the Science Museum aims to give a flavour of Turing the individual, and thus the exhibition mixes illustrations of the importance of his academic achievements with exhibits from the personal life of the man himself.

As the article points out, Turing is probably better known to the public for his wartime codebreaking work than for his work in mathematics.  His 1936 paper, On Computable Numbers, with an Application to the Entscheidungsproblem [PDF], in which he described the computing device we now know as a Turing machine, is certainly not light reading.  And computers, especially modern ones, aren’t really all that interesting to look at.  The Pilot ACE is old enough to have a console and visible electronic components.

It sounds like a most interesting exhibit.


Alan Turing Centenary, Part 2

June 23, 2012

As one might expect, the BBC News site has a number of articles related to the Alan Turing Centenary.  In particular, it has been publishing  a series of essays on Turing’s life and work.   I have tried to give a brief overview of these below.  (The essays are set up as separate pages, but there is a set of links to all of them at the top of each article.)

The first essay, on “Turing’s Genius”, is by Google’s Vint Cerf, who I have mentioned before in connection with the ACM’s participation in the Turing Centenary, and who is a recipient of the ACM’s Turing Award.  (As he mentions in his essay, he also, coincidentally, shares a birthday with Turing: June 23.)  He discusses the many ways in which Turing’s original work relates to the technological world we all take for granted today.

The second essay, by Prof. Jack Copeland, University of Canterbury, Christchurch, New Zealand, relates Turing’s involvement in code-breaking at the Government Code and Cypher School at Bletchley Park (also called Station X).  It mentions Turing’s personal contribution to breaking the naval version of the German Enigma encryption system, and the Lorenz cipher.   These mathematical, cryptanalytic contributions would have been impressive; but Turing also made an enormous contribution to the work of turning Station X into what was, in effect, the world’s first code-breaking factory.  He helped develop the bombes, electro-mechanical computers used to break Enigma messages on a production basis, and the Tunny machine, used for the Lorenz cipher.   (A project to reconstruct a Tunny machine is underway.)  As in many aspects of wartime intelligence, time was of the essence.

The faster the messages could be broken, the fresher the intelligence that they contained, and on at least one occasion an intercepted Enigma message’s English translation was being read at the British Admiralty less than 15 minutes after the Germans had transmitted it.

The third essay, “Alan Turing: The Father of Computing?”, is by Prof. Simon Lavington, author of Alan Turing and His Contemporaries: Building the World’s First Computers.   He observes that Turing’s ideas were not always terribly influential in some of the early computer  implementations.

It was not until the late 1960s, at a time when computer scientists had started to consider whether programs could be proved correct, that On Computable Numbers came to be widely regarded as the seminal paper in the theory of computation.

On Computable Numbers, with an Application to the Entscheidungsproblem [PDF], Turing’s paper, proved nonetheless to be of immense importance.  In it, Turing laid out, for the first time as far as I know, the  idea of a theoretical machine that, as demonstrated in his mathematical analysis, could solve any solvable problem.

The fourth essay, by Prof. Noel Sharkey of the University of Sheffield, discusses the Turing Test, proposed by Turing in his 1950 paper, Computing Machinery and Intelligence.  That paper begins with a statement of the fundamental problem:

I propose to consider the question, ‘Can machines think ?’  This should begin with definitions of the meaning of the terms ‘machine ‘ and ‘ think ‘.

Turing’s paper was provocative, in part, because he realized how woolly the question, “Can machines think?”, really is   There are ongoing discussions of whether the test that Turing proposed is the right one, but it does have the considerable virtue of being realizable in practice.


Alan Turing Centenary, Part 1

June 19, 2012

I’ve written here a couple of time about the Alan Turing Centenary, marking the 100th anniversary of of the birth of the English mathematician, cryptanalyst, and pioneer computer scientist; and about some of the events planned for the occasion.  This coming Saturday, June 23, is Turing’s birthday, so there will undoubtedly be more events and tributes to follow.  In this, and subsequent posts, I’ll attempt to highlight some of the more interesting items that I come across.

Although it is not new, one item that deserves to be on the list is the wonderful biography of Turing by Andrew Hodges, Alan Turing: The Enigma.   Hodges also maintains The Alan Turing Home Page, a Web site dedicated to Turing.  It includes a short on-line biography, a scrapbook, and links to documents and publications.

Ars Technica has an article about Turing’s life and work, “The Highly Productive Habits of Alan Turing”, by Matthew Lasar, lecturer in history at the University of California, Santa Cruz.  It gives a good brief overview of Turing’s work, organized under seven “productive habits”:

  1. Try to see things as they are.
  2. Don’t get sidetracked by ideologies.
  3. Be practical.
  4. Break big problems down into smaller tasks.
  5. Just keep going.
  6. Be playful.
  7. Remember that it is people who matter.

If you aren’t familiar with Turing at all, this article is a good place to get the highlights quickly.

Wired has a couple of items on Turing.  The first is another brief biographical sketch, in the form of a time line of Turing’s life and work.  It mentions one occasion that I had forgotten: in the early 1950s, Turing wrote a program to play chess.  This was (pace Habit 3 above) not a very practical exercise, since at that time there was no computer powerful enough to run the program.  Turing tested the program by using an emulator — himself — executing the program with pencil and paper.

The second article at Wired is a more subjective look at some of Turing’s accomplishments.  It focuses mostly on his wartime work at the Government Code and Cypher School at Bletchley Park (also known as Station X), breaking the German’s Enigma encryption system, and on his work in computer science.  It also mentions Turing’s only paper on biology, “The Chemical Basis of Morphogenesis”, published in 1952.  Oddly, it doesn’t mention one of his best-known works, the essay Computing Machinery and Intelligence, published in October 1950 in the Oxford journal Mind, in which he proposes the “imitation game”, the Turing test of intelligence.

I’ll post additional items as I come across them.


ACM to Celebrate Turing Centenary

June 16, 2012

Last October, I posted a note here about the upcoming 100-year anniversary of the birth of Alan Turing, the English mathematician and pioneer computer scientist.  Turing was a central figure in the successful British effort, at Bletchley Park, to break coded messages produced by the Germans’ Enigma cipher machine.  Some of Turing’s theoretical papers on cryptanalysis have been declassified only recently.

Network World has an article about some additional activities planned by the Association for Computing Machinery [ACM] around the anniversary, which is June 23.   Vint Cerf of Google, a noted computer scientist in his own right, is president-elect of the ACM and chair of the organization’s commemorative events, points out how fundamental Turing’s work is to modern computer science.

“Alan had such a broad impact on so many aspects of computer science,” says Cerf. “The deep notion of computability is so fundamental to everything we do in computing.”

In designing a hypothetical computing device, which we now know as a Turing machine, Turing provided a framework for analysing the possibilities and limitations of mechanical, and electronic, computing devices.

Since 1966, the ACM has given out its annual Turing Award, sometimes referred to as the “Nobel Prize” of computer science, to “an individual selected for contributions of a technical nature made to the computing community”.   (Vint Cerf received a Turing Award in 2004.)  This year, at an event to be held in San Francisco June 15-16, the ACM is trying to assemble all living Turing Award recipients, and will feature talks and panel discussions on Turing’s life and work.

Turing, who was named one of Time magazine’s 100 Most Important People of the [20th] Century, would have been an important figure even if the war had never occurred.  It is good to see that his contributions are being more fully appreciated.


Code-Breaking Papers by Turing Released

April 19, 2012

The BBC News site is reporting that the UK Government Communication Headquarters [GCHQ] has released two papers by Alan Turing on the mathematical theory of cryptanalysis (code breaking).  (GCHQ is roughly analogous to the US National Security Agency.)    The papers had been classified since Turing wrote them, approximately 70 years ago, apparently while he was working at Bletchley Park.

The papers, one entitled The Applications of Probability to Crypt, and the other entitled Paper on the Statistics of Repetitions, discuss mathematical approaches to code breaking.

A GCHQ mathematician said the fact that the contents had been restricted “shows what a tremendous importance it has in the foundations of our subject”

According to the BBC report, the papers have been given to the UK National Archives, although the news does not seem to have made it onto the Archives’ site yet.

(There is one small aspect of the BBC’s article that I found amusing.  It has an image of a small section of a page from one of the papers, with the notation, “The papers are typed but contain hand written notes, tables and formulae.”    Well, yes.  That is the way we produced technical papers back in the days of stone tools.)

The release of these papers is timely, too, in this year which marks the centenary of Turing’s birth.  It is good to see that his many contributions in mathematics and computer science are being recognized.


The Digital Big Bang

March 12, 2012

Recently, in a couple of posts about some recently declassified correspondence between the mathematician John Nash and the National Security Agency, I mentioned the confluence of very bright people in and around Princeton NJ shortly before, during, and after World War II.  Besides John Nash, the list includes Albert Einstein, John von Neumann, Kurt Gödel, and Alan Turing.  Another was the theoretical physicist Freeman Dyson, now Professor Emeritus at the Institute for Advanced Study (IAS).

I have just come across another discussion of that period, in the form of an interview at Wired with the science historian George Dyson, Freeman Dyson’s son.  concerning his new book on the origins of modern computing, Turing’s Cathedral.  George Dyson grew up in Princeton, while his father was at the IAS, and had some direct personal experience with some of the early computer development there.

The institute was a pretty boring place, full of theoreticians writing papers. But in a building far away from everyone else, some engineers were building a computer, one of the first to have a fully electronic random-access memory. For a kid in the 1950s, it was the most exciting thing around. I mean, they called it the MANIAC!

After the work of the Manhattan Project in developing the atomic bomb, von Neumann had persuaded the US government to fund the development of a digital computer, to be used for the development of the hydrogen bomb.  Although there were other early computers, including ENIAC and EDSAC, the development was significant, because it was the first computer to have a fully modern stored-program architecture (which is still called a von Neumann architecture).

George Dyson’s initial fascination with the project apparently developed into a more apprehensive feeling a little later, when he tried to distance himself from computers.

Computers were going to take over the world. So I left high school in the 1960s to live on the islands of British Columbia. I worked on boats and built a house 95 feet up in a Douglas fir tree. I wasn’t anti-technology; I loved chain saws and tools and diesel engines. But I wanted to keep my distance from computers.

He eventually returned to study digital development, because he was struck by the similarities between the biological and digital worlds.

When I looked at the digital universe, I saw the tracks of organisms coming to life. I eventually came out of the Canadian rain forest to study this stuff because it was as wild as anything in the woods.

In the balance of the interview, Dyson talks about some of the people most directly involved in the project, including Turing, von Neumann, and Julian Bigelow, the engineer who directed the actual construction — a difficult job just after the war, when many materials and facilities were hard to come by.   The biologist Nils Barricelli used the machine to simulate the evolution of digital “life forms” when it was not busy simulating thermonuclear explosions.  Dyson also makes an interesting observation about a side effect of the early hardware’s unreliability.

Vacuum tubes in the early machines had an extremely high failure rate, and von Neumann and Turing both spent a lot of time thinking about how to tolerate or even take advantage of that. If you had unreliable tubes, you couldn’t be sure you had the correct answer, so you had to run a problem at least twice to make sure you got the same result. Turing and von Neumann both believed the future belonged to nondeterministic computation and statistical, probabilistic codes.

As Dyson points out, the idea of probabilistic computations has produced some intriguing results recently, in areas like language translation, as well as in IBM’s Watson project.

Although I have not yet got my hands on a copy of Dyson’s book, it sounds most interesting  There is a review at The Economist, and another at The Wall Street Journal.


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