Category: Computer History

RADAR winning the Battle of Britain

Plaque commemorating the Birth of RADAR
Image Kintak, CC BY-SA 3.0 via Wikimedia Commons

The traditional story of how World War II was won is that of inspiring leaders, brilliant generals and plucky Brits with “Blitz Spirit”. In reality it is usually better technology that wins wars. Once that meant better weapons, but in World War II, mathematicians and computer scientists were instrumental in winning the war by cracking the German codes using both maths and machines. It is easy to be a brilliant general when you know the other sides plans in advance!. Less celebrated but just as important, weathermen and electronic engineers were also instrumental in winning World War II, and especially, the Battle of Britain, with the invention of RADAR. It is much easier to win an air battle when you know exactly where the opposition’s planes. It was down largely to meteorologist and electronic engineer, Robert Watson-Watt and his assistant Arnold Wilkins. Their story is told in the wonderful, but under-rated, film Castles in the Sky, starring Eddie Izzard.

****SPOILER ALERT****

In the 1930s, Nazi Germany looked like an ever increasing threat as it ramped up it’s militarisation, building a vast army and air force. Britain was way behind in the size of its air force. Should Germany decide to bomb Britain into submission it would be a totally one-sided battle. SOmething needed to be done.

A hopeful plan was hatched in the mid 1930s to build a death ray to zap pilots in attacking planes. One of the engineers asked to look into the idea was Robert Watson-Watt. He worked for the met office. He was an expert in the practical use of radio waves. He had pioneered the idea of tracking thunderstorms using the radio emissions from lightening as a warning system for planes, developing the idea as early as 1915. This ultimately led to the invention of “Huff-Duff”, shorthand for High Frequency Direction Finding, where radio sources could be accurately tracked from the signals they emitted. That system helped Britain win the U-Boat war, in the North Atlantic, as it allowed anti-submarine ships to detect and track U-Boats when they surfaced to use their radio. As a result Huff-Duff helped sink a quarter of the U-Boats that were attacked. That in itself was vital for Britain to survive the siege that the U-Boats were enforcing sinking convoys of supplies from the US.

However, by the 1930s Watson-Watt was working on other applications based on his understanding of radio. His assistant, Arnold Wilkins, quickly proved that the death ray idea would never work, but pointed out that planes seemed to affect radio waves. Together they instead came up with the idea of creating a radio detection system for planes. Many others had played with similar ideas, including German engineers, but no one had made a working system.

Because the French coast was only 20 minutes flying time away the only way to defend against German bombers would be to have planes patrolling the skies constantly. But that required vastly more planes than Britain could possibly build. If planes could be detected from sufficiently far away, then Spitfires could instead be scrambled to intercept them only when needed. That was the plan, but could it be made to work, when so little progress had been made by others?

Watson-Watt and Wilkins set to work making a prototype which they successfully demonstrated could detect a plane in the air (if only when it was close by). It was enough to get them money and a team to keep working on the idea. Watson-Watt followed a maxim of “Give them the third best to go on with; the second best comes too late, the best never comes”. With his radar system he did not come up with a perfect system, but with something that was good enough. His team just used off-the shelf components rather than designing better ones specifically for the job. Also, once they got something that worked they put it into action. Unlike later, better systems their original radar system didn’t involve sweeping radar signals that bounced off a plane when the sweep pointed at it, but a radio signal blasted in all directions. The position of the plane was determined by a direction finding system Watson-Watt designed based on where the radio signal bounced back from. That meant it took lots of power. However, it worked, and a network of antennas were set up in time for the Battle of Britain. Their radar system, codenamed Chain Home could detect planes 100 miles away. That was plenty of time to scramble planes. The real difficulty was actually getting the information to the air fields to scramble the pilots quickly. That was eventually solved with a better communication system.

The Germans were aware of all the antenna, appearing along the British coast but decided it must be a communications system. Carrots also helped fool them! You may of heard that carrots help you see in the dark. That was just war-time propaganda invented to explain away the ability of the Brits to detect bombers so soon…a story was circulated that due to rationing Brits were eating lots of carrots so had incredible eye-sight as a result!

The Spitfires and their fighter pilots got all the glory and fame, but without radar they would not even have been off the ground before the bombers had dropped their payloads. Practical electronic engineering, Robert Watson-Watt and Arnold Wilkins were the real unsung heroes of the Battle of Britain.

– Paul Curzon, Queen Mary University of London

Postscript

In the 1950s Watson-Watt was caught speeding by a radar speed trap. He wrote a poem about it:

A Rough Justice

by Sir Robert Watson-Watt

Pity Sir Watson-Watt,
strange target of this radar plot

And thus, with others I can mention,
the victim of his own invention.

His magical all-seeing eye
enabled cloud-bound planes to fly

but now by some ironic twist
it spots the speeding motorist

and bites, no doubt with legal wit,
the hand that once created it.

…

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Sea sounds sink ships

A shoal of silvery blue fish densely packed and swimming together
Shoal of fish in the Galapagos image by Christopher Chilton from Pixabay

You might think that under the sea things are nice and quiet, but something fishy is going on down there. Our oceans are filled with natural noise. This is called ambient noise and comes from lots of different sources: from the sound of winds blowing waves on the surface, rain, distant ships and even underwater volcanoes. For undersea marine life that relies on sonar or other acoustic ways to communicate and navigate all the extra ocean noise pollution that human activities, such as undersea mining and powerful ships sonars, have caused, is an increasing problem. But it’s not only the marine life that is affected by the levels of sea sounds, submarines also need to know something about all that ambient noise.

In the early 1900s the aptly named ‘Submarine signal company’ made their living by installing undersea bells near lighthouses. The sound of these bells were a warning to mariners about the impending navigation hazards: an auditory version of the lighthouse light.

The Second World War led to scientists taking undersea ambient noise more seriously as they developed deadly acoustic mines. These are explosive mines triggered by the sound of a passing ship. To make the acoustic trigger work reliably the scientists needed to measure ambient sound, or the mines would explode while simply floating in the water. Measurements of sound frequencies were taken in harbours and coastal waters, and from these a mathematical formula was computed that gave them the ‘Knudsen curves’. Named after the scientist who led the research these curves showed how undersea sound frequencies varies with surface wind speed and wave height. They allowed the acoustic triggers to be set to make the mines most effective.

– Peter McOwan, Queen Mary University of London

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Mary and Eliza Edwards: the mother and daughter human computers

The globe with lines of longitude marked
Lines of Longitude. Image from wikimedia, Public Domain.

Mary Edwards was a computer, a human computer. Even more surprisingly for the time (the 1700s), she was a female computer (and so was her daughter Eliza).

In the early 1700s navigation at sea was a big problem. In particular, if you were lost in the middle of the Atlantic Ocean, there was no good way to determine your longitude, your position east to west. There was of course no satnavs at the time not least because there would be no satellites for 300 years! 

It could be done based on taking sightings of the position of the sun, moon or planets, at different times of the day, but only if you had an accurate time. Unfortunately, there was no good way to know the precise time when at sea. Then in the mid 1700s, an accurate clock that could survive a rough sea voyage and still be highly accurate was invented by clockmaker John Harrison. Now the problem moved to helping mariners know where the moon and planets were supposed to be at any given time so they could use the method.

As a result, the Board of Longitude (set up by the UK government to solve the problem) with the Royal Greenwich Observatory started to publish the Nautical Almanac from 1767. It consisted lots of information of such astronomical data for use by navigators at sea. For example, it contained tables of the position of the moon (or specifically its angle in the sky relative to the sun and planets (known as lunar distances). But how were these angles known years in advance to create the annual almanacs? Well, basic Newtonian physics allow the positions of planets and the moon to be calculated based on how everything in the solar system moves together with their positions at a known time. From that their position in the sky at any time can be calculated. That answers would be in the Nautical Almanac. Each year a new table was needed, so the answers also needed to be constantly recomputed.

But who did the complex calculations? No calculators, computers or other machines that could do it automatically would exist for several hundred years. It had to be done by human mathematicians. Computers then were just people, following algorithms, precisely and accurately, to get jobs like this done. Astronomer Royal, Nevil Maskelyne recruited 35 male mathematicians to do the job. One was the Revd John Edwards (well-educated clergy were of course perfectly capable of doing maths in their spare time!). He was paid for calculations done at home from 1773 until he died in 1884.

However, when he died Maskelyne received a letter from his wife Mary, revealing officially that in fact she had been doing a lot of the calculations herself, and with no family income any more she asked if she could continue to do the work to support herself and her daughters. Given the work had been of high enough quality that John Edwards had been kept on year after year so Mary was clearly an asset to the project, (and given he had visited the family several times so knew them, and was possibly even unofficially aware who was actually doing the work towards the end) Maskelyne was open-minded enough to give her a full time job. She worked as a human computer until her death 30 years later. Women doing such work was not at all normal at the time and this became apparent when Maskelyne himself died and the work stated to dry up. The quality of the work she did do, though, eventually persuaded the new Astronomer Royal  to continue to give her work.

Just as she helped her husband, her daughter Eliza helped her do the calculations, becoming proficient enough herself that when Mary died, Eliza took over the job, continuing the family business for another 17 years. Unfortunately, however, in 1832, the work was moved to a new body called ‘His Majesty’s Nautical Almanac Office’ At that point, despite Mary and Eliza having proved they were at least as good as the men for half a century or more, government imposed civil service rules came into force that meant women could no longer be employed to do the work.

Mary and Eliza, however had done lots of good, helping mariners safely navigate the oceans for very many years through their work as computers.

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Film Futures: The Lord of the Rings

Image by Ondřej Neduchal from Pixabay

What if there was Computer Science in Middle Earth?…Computer Scientists and digital artists are behind the fabulous special effects and computer generated imagery we see in today’s movies, but for a bit of fun, in this series, we look at how movie plots could change if they involved Computer Scientists. Here we look at an alternative version of the film series (and of course book trilogy): The Lord of the Rings.

***SPOILER ALERT***

The Lord of the Rings is an Oscar winning film series by Peter Jackson. It follows the story of Frodo as he tries to destroy the darkly magical, controlling One Ring of Power, by throwing it in to the fires of Mount Doom at Mordor. This involves a three film epic journey across Middle Earth where he and “the company of the Ring” are chased by the Nazgûl, the Ringwraiths of the evil Sauron. Their aim is to get to Mordor, without being killed and the Ring taken from them and returned to Sauron who created it, or it being stolen by Golem who once owned it.

The Lord of the Rings: with computer science

In our computer science film future version, Frodo discovers there is a better way than setting out on a long and dangerous quest. Aragorn, has been tinkering with drones in his spare time, and so builds a drone to carry the Ring to Mount Doom controlled remotely. Frodo pilots it from the safety of Rivendell. However, on its first test flight, its radio signal is jammed by the magic of Saruman from his tower. The drone crashes and is lost. It looks like a the company must set off on a quest after all.

However, the wise Elf, the Lady Galadriel suggests that they control the drone by impossible-to-jam fibre optic cable. The Elves are experts at creating such cables using them in their highly sophisticated communication networks that span Middle Earth (unknown to the other peoples of Middle Earth), sending messages encoded in light down the cables.

They create a huge spool containing the hundreds of miles needed. Having also learnt from their first attempt, they build a new drone that uses stealth technology devised by Gandalf to make it invisible to the magic of Wizards, bouncing magical signals off it in a way that means even the ever watchful Eye of Sauron does not detect it until it is too late. The new drone sets off trailing a fine strand of silk-like cable behind, with the One Ring within. At its destination, the drone is piloted into the lava of Mount Doom, destroying the ring forever. Sauron’s power collapses, and peace returns to Middle Earth. Frodo does not suffer from post-traumatic stress disorder, and lives happily ever after, though what becomes of Golem is unknown (he was last seen on Mount Doom through the Drones camera, chasing after it, as the drone was piloted into the crater).

In real life…

Drones are being touted for lots of roles, from delivering packages to people’s doors to helping in disaster emergency areas. They have most quickly found their place as a weapon, however. At regular intervals a new technology changes war forever, whether it is the long bow, the musket, the cannon, the tank, the plane… The most recent technology to change warfare on the battlefield has been the introduction of drone technology. It is essentially the use of robots in warfare, just remote controlled, flying ones rather than autonomous humanoid ones, Terminator style (but watch this space – the military are not ones to hold back on a ‘good’ idea). The vast majority of deaths in the Russia-Ukraine war on both sides have been caused by drone strikes. Now countries around the world are scrambling to update their battle readiness, adding drones into their defence plans.

The earliest drones to be used on the battlefield were remote controlled by radio, The trouble with anything controlled that way is it is very easy to jam – either sending your own signals at higher power to take over control, or more easily to just swamp the airwaves with signal so the one controlling the drone does not get through. The need to avoid weapons being jammed is not a new problem. In World War II, some early torpedoes were radio controlled to their target, but that became ineffectual as jamming technology was introduced. Movie star Hedy Lamar is famous for patenting a mechanism whereby a torpedo could be controlled by radio signals that jumped from frequency to frequency, making it harder to jam (without knowing the exact sequence and timing of the frequency jumps). In London, torpedo stations protecting the Thames from enemy shipping had torpedoes controlled by wire so they could be guided all the way to the target. Unfortunately though it was not a great success, the only time one was used in a test it blew up a harmless fishing boat passing by (luckily no-one died).

And that is the solution adopted by both sides in the Ukraine war to overcome jamming. Drones flying across the front lines are controlled by miles of fibre optic cable that is run out on spools (tens of miles rather than the hundreds we suggested above). The light signals controlling the drone, pass down the glass fibre so cannot be jammed or interfered with. As a result the front lines in the Ukraine are now criss-crossed with gossamer thin fibres, left behind once the drones hit their target or are taken out by the opposing side. It looks as though the war is being fought by robotic spiders (which one day may be the case but not yet). With this advent of fibre-optic drone control, the war has changed again and new defences against this new technology are needed. By the time they are effective, likely the technology will have morphed into something new once more.

– Paul Curzon, Queen Mary University of London

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The first Internet concert

Severe Tire Damage
Severe Tire Damage. Image by Strubin, CC BY-SA 4.0 via Wikimedia Commons

Which band was the first to stream a concert live over the Internet? The Rolling Stones decided, in 1994, it should be them. After all, they were one of the greatest, most innovative rock bands of all time. A concert from their tour of that year, in Dallas, was therefore broadcast live. Mick Jagger addressed the world not just the 50,000 packed into the stadium welcoming the world with “I wanna say a special welcome to everyone that’s, climbed into the Internet tonight and, uh, has got into the MBone. And I hope it doesn’t all collapse.” Unknown to them, when planning this publicity coup, another band had got there first: a band of Computer Scientists from Xerox PARC, DEC and Apple, the research centres responsible for many innovations including many of the ideas around graphical user interfaces, networks and multimedia internet had played live on the Internet the year before!

The band which actually went down in history was called Severe Tire Damage. Its members were Russ Haines and Mark Manasse (from DEC), Steven Rubin (a Computer Aided design expert from Apple) and Mark Weiser (famous for the ideas behind calm computing, from Xerox PARC). They were playing a concert at Xerox PARC on  June 24, 1993. At the time researchers there were working on a system called MBone which provided a way to do multimedia over the Internet for the first time. Now we take that for granted (just about everyone with a computer or phone doing Zoom and Teams calls, for example) but then the Internet was only set up for exchanging text and images from one person to another. MBone, short for multicast backbone, allowed packets of data of any kind (so including video data) from one source to be sent to multiple Internet addresses rather than just to one address. Sites that joined the MBone could send and receive multimedia data, including video, live to all the others in one broadcast. This meant for the first time, video calls between multiple people over the Internet were possible. They needed to test the system, of course, so set up a camera in front of Severe Tire Damage and live-streamed their performance to other researchers on the nascent MBone round the world (research can be fun at the same time as being serious!). Possibly there was only a single Australian researcher watching at the time, but it is the principle that counts!

On hearing about the publicity around the Rolling Stones concert, and understanding the technology of course, they decided it was time for one more live internet gig to secure their place in history. Immediately, before the Rolling Stones started their gig, Severe Tire Damage broadcast their own live concert over the MBone to all those (including journalists) waiting for the main act to arrive online. In effect they had set themselves up as an Internet un-billed opening act for the Stones even though they were nowhere near Dallas. Of course that is partly the point, you no longer had to all be on one place to be part of the same concert. So, the Rolling Stones, sadly for them, weren’t even the first to play live over the Internet on that particular day, never mind ever!

– Paul Curzon, Queen Mary University of London

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Was the first computer a ‘Bombe’?

Image from a set of wartime photos of GC&CS at Bletchley Park, Public domain, via Wikimedia Commons

A group of enthusiasts at Bletchley Park, the top secret wartime codebreaking base, rebuilt a primitive computing device used in the Second World War to help the Allies listen in on U-boat conversations. It was called ‘the Bombe’. Professor Nigel Smart, now at KU Leuven and an expert on cryptography, tells us more.

So What’s all this fuss about building “A Bombe”? What’s a Bombe?

The Bombe didn’t help win the war destructively like its explosive name-sakes but using intelligence. It was designed to find the passwords or ‘keys’ into the secret codes of ‘Enigma’: the famous encryption machine used both by the German army in the field and to communicate to U-Boats in the Atlantic. It effectively allowed the English to listen in to the German’s secret communications.

A Bombe is an electro-mechanical special purpose computing device. ‘Electro-mechanical’ because it works using both mechanics and electricity. It works by passing electricity through a circuit. The precise circuit that is used is modified mechanically on each step of the machine by drums that rotate. It used a set of rotating drums to mirror the way the Enigma machine used a set of discs which rotated when each letter was encrypted. The Bombe is a ‘special purpose’ computing device rather than a ‘general purpose’ computer because it can’t be used to solve any other problem than the one it was designed for.

Why Bombe?

There are many explanations of why it’s called a ‘Bombe’. The most popular is that it is named after an earlier, but unrelated, machine built by the Polish to help break Enigma called the Bomba. The Bomba was also an electro-mechanical machine and was called that because as it ran it made a ticking sound, rather like a clock-based fuse on an exploding bomb.

What problem did it solve?

The Enigma machine used a different main key, or password, every day. It was then altered slightly for each message by a small indicator sent at the beginning of each message. The goal of the codebreakers at Bletchley Park each day was to find the German key for that day. Once this was found it was easy to then decrypt all the day’s messages. The Bombe’s task was to find this day key. It was introduced when the procedures used by the Germans to operate the Enigma changed. This had meant that the existing techniques used by the Allies to break the Enigma codes could no longer be used. They could no longer crack the German codes fast enough by humans alone.

So how did it help?

The basic idea was that many messages sent would consist of some short piece of predictable text such as “The weather today will be….” Then using this guess for the message that was being encrypted the cryptographers would take each encrypted message in turn and decide whether it was likely that it could have been an encryption of the guessed message. The fact that the German army was trained to say and write “Heil Hitler” at any opportunity was a great help too!

The words “Heil, Hitler” help the German’s lose the war

If they found one that was a possible match they would analyze the message in more detail to produce a “menu”. A menu was just what computer scientists today call a ‘graph’. It is a set of nodes and edges, where the nodes are letters of the alphabet and the edges link the letters together a bit like the way a London tube map links stations (the nodes) by tube lines (the edges). If the graph had suitable mathematical properties that they checked for, then the codebreakers knew that the Bombe might be able to find the day key from the graph.

The menu, or graph, was then sent over to one of the Bombe’s. They were operated by a team of women – the World’s first team of computer operators. The operator programmed the Bombe by using wires to connect letters together on the Bombe according to the edges of the menu. The Bombe was then set running. Every so often it would stop and the operator would write down the possible day key which it had just found. Finally another group checked this possible day key to see if the Bombe had produced the correct one. Sometimes it had, sometimes not.

So was the Bombe a computer?

By a computer today we usually mean something which can do many things. The reason the computer is so powerful is that we can purchase one piece of equipment and then use this to run many applications and solve many problems. It would be a big problem if we needed to buy one machine to write letters, one machine to run a spreadsheet, one machine to play “Grand Theft Auto” and one machine to play “Solitaire”. So, in this sense the Bombe was not a computer. It could only solve one problem: cracking the Enigma keys.

Whilst the operator programmed the Bombe using the menu, they were not changing the basic operation of the machine. The programming of the Bombe is more like the data entry we do on modern computers.

Alan Turing who helped design the Bombe along with Gordon Welchman, is often called the father of the computer, but that’s not for his work on the Bombe. It’s for two other reasons. Firstly before the war he had the idea of a theoretical machine which could be programmed to solve any problem, just like our modern computers. Then, after the war he used the experience of working at Bletchley to help build some of the worlds first computers in the UK.

But wasn’t the first computer built at Bletchley?

Yes, Bletchley park did build the first computer as we would call it. This was a machine called Colossus. Colossus was used to break a different German encryption machine called the Lorenz cipher. The Colossus was a true computer as it could be used to not only break the Lorenz cipher, but it could also be used to solve a host of other problems. It also worked using digital data, namely the set of ones and zeros which modern computers now operate on.

– Nigel Smart, KU Leuven

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The CS4FN Easter Egg Hunt

Image by Susanne from Pixabay

Easter eggs can be chocolate but they are also hidden treasures to be found in games, websites, other software (and now even Lego sets). Especially for Easter we have hidden an Easter Egg in one of our diversity linked pages. Can you find it? Enjoy the hunt! (But if you do find it don’t give it away and spoil the fun for others. Just be quietly pleased at how clever you are!)

The term Easter Egg was coined after Warren Robinett hid the message “Created by Warren Robinett” in the Atari game, Adventure, that he created. He did it as part of a plan he hatched to protest against the Atari policy of the time of not crediting the developers of their games – supposedly so their best people wouldn’t get poached by rivals!! The real purpose of the game was to find a hidden chalice, but the hidden message could be found if the player’s avatar (a square block) stopped over one specific pixel (“the gray dot”) in one specific place in the game.

It was only found (by a player) after Warren had left the company (he hadn’t let on to the management what he had done even when he resigned). Originally the company scrambled to try to re-release the game without the message, but given how expensive that would have been to do, instead they turned it into a feature to whip up more excitement around their games and started to hide similar surprises in other games from then on, calling them Easter Eggs.

The Easter Egg was born.

Start your hunt for our Easter Egg here at our diversity portal.

As an aside, the wonderful book, Ready Player One by Ernest Cline is based on a plot around finding Easter Eggs. It is a must read for anyone interested in 1980s technology, easter eggs and what a metaverse might one day be actually like to live in. All computer scientists should read it (and only then watch the film which is good, but not as good.)

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Hint – we think you will never see it without some help.

Dina St Johnston: Kickstarting a software industry

Back in its early days, after the war, women played a pivotal role in the computing industry, originally as skilled computer operators. Soon they started to be taken on as skilled computer programmers too. The myth that programming is boys thing came much later. Originally it was very much a job for women too. Dina St Johnston was one such early programmer. And she personally went on to kick-start the whole independent UK software industry!

Departure Board Kings Cross showing times, platform, destinations
Image Public Domain from wikimedia

On leaving school, interested in maths, science and machines, she went to work for a metallurgy research company, and in parallel gained a University of London external Maths degree, but eventually moved on to get a job ultimately as a programmer at an early computer manufacturer, Elliot Brothers in 1053. Early software she was involved in writing was very varied, but whatever the application she excelled. For example, she was responsible for writing an in-house payroll program, as well as code for a dedicated direction finding computer of the Royal Navy. The latter was a system that used the direction of radio signals picked up by receivers at different listening stations to work out where the source was (whether friend or foe). She also wrote software for the first computer to be used by a local government, Norwich City Council. She had the kind of attention to detail and logical thinking skills that meant she quickly became an incredibly good programmer, able to write correct code. Bugs for others to find in her code were rare. “Whereas the rest of us tested programs to find the faults, she tested them to demonstrate that they worked.”

Towards the end of the 1960s though she realised there was a big opportunity, a gap in the market, for someone with programming skills and a strong entrepreneurial spirit like her. All UK application software at the time was developed either by computer manufacturers like Elliot Brothers, by service companies selling time on their computers, by consultancy firms or in-house by people working directly for the companies who bought the computers. There was, she saw, potential to create a whole new industry: an applications software industry. What there was a need for, were independent software companies whose purpose was to write bespoke application programs that were just what a client company needed, for any who needed it, big or small. She therefore left Elliot Brothers and founded her own company (named after her maiden name), Vaughan Programming Services, to do just that.

Despite starting out working from her dining room table, it was a big success, working in a lot of different application areas over the subsequent decades, with clients including massive organisations such as the BBC, BAA, Unilever, GEC, the nuclear industry (she wrote software for what is now called Sellafield, then the first ever industrial nuclear power plant), the RAF and British Rail. Part of the reason she made it work was she was a programmer who was “happy to go round a steel works in a hard hat”, She made sure she understood her clients needs in a direct hands-on way.

Eventually, Dina’s company started to specialise in transport information systems and that is where it really made its name…with early work for example on the passenger display boards at London Bridge, but eventually to hundreds of stations, driven from a master timetable system. So next time you are in a train station or airport, looking at the departure board, think of Dina, as it was her company that wrote the code driving the forerunner of the display you are looking at.

More than that though, the whole idea of a separate software industry to create whatever programs were needed for whoever needed them, started with her. If you are a girl wondering about whether a software industry job is for you, as she showed, there is absolutely no reason why it should not be. Dina excelled, so can you.

by Paul Curzon, Queen Mary University of London

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Tanaka Atsuko: an electric dress

Wearable computing is now increasingly common whether wearing smart watches or clothes that light up. The pioneer of the latter was Japanese artist, Tanaka Atsuko, with her 1950s art work, Electric Dress. It was anything but light though, weighing 50-60kg, clothing her head to foot in a mixture of fluorescent and normal light bulbs.

Light reflecting from strip bulbs in a light bulb
Image by wal_172619 from Pixabay

She was a member of the influential Gutai (meaning concrete as opposed to abstract) Art Association and Zero Society of Japanese artists who pioneered highly experimental performance and conceptual art, that often included the artist’s actual body. The Electric Dress was an example of this, and she experimented with combining art and electronics in other work too.

Atsuko had studied dress-making as well as art, and did dress making as a hobby, so fashion was perhaps a likely way for her to express her artistic ideas, but Electric Dress was much more than just fashion as a medium for art. She had the idea of the dress when surrounded by the fluorescent lights in Osaka city centre. She set about designing and making the dress and ultimately walked around the gallery wearing it when it was exhibited at the 2nd Gutai Art Exhibition in Tokyo. Once on it flashed the lights randomly, bathing her in multicoloured light. Wearing it was potentially dangerous. It was incredibly hot and the light was dazzling. There was also a risk of electrocution if anything went wrong! She is quoted as saying after wearing it: “I had the fleeting thought: Is this how a death-row inmate would feel?”

It wasn’t the first time, electric lights had been worn, since as early as 1884 you could hire women, wearing lights on their heads powered by batteries hidden in their clothes, to light up a cocktail party, for example. However, Tanaka Atsuko’s was certainly the most extreme and influential version of a light dress, and shows how art and artists can inspire new ideas in technology. Up to then, what constituted wearable computing was more about watch like gadgets than adding electronics or computing to clothes.

Now, of course, with LEDs, and conductive thread that can be sewn into clothes and special micro-controllers, an electric dress is both much easier to make, and with programming skill you can program the lights in all sorts of creative ways. One example is a dress created for a BBC educational special of Strictly Come Dancing promoting the BBC micro:bit and showing what it was capable of with creativity. Worn by professional dancer, Karen Hauer, in a special dance to show it off, the micro:bit’s accelerometer was used to control the way the LEDs covering the dress in place of sequins, lit up in patterns. The faster she spun while dancing the more furious the patterns of the lights flashing.

Now you can easily buy kits to create your own computer-controlled clothes with online guides to get you started, so if interested in fashion and computer science why not start experimenting. Unlike Tanaka Atsuko you won’t have to put your life at risk for your art and wearable computing, overlapping with soft robotics is now a major research area, so it could be the start of a great research career.

by Paul Curzon, Queen Mary University of London

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The logic piano

Piano keys
Image by Elisa from Pixabay

Victorian, William Stanley Jevons was born in Liverpool in 1835. He was famous in his day as an economist and his smash hit book ‘The Coal Question’ drew the nation’s attention to the reduction in Britain’s coal supplies. He was the first economist to raise the issue of the ecological impact of economics. Jevons had other strings to his bow though and one of the strangest for the time if also incredibly forward thinking was his 1869 “logic piano”: a device that looked a little like a piano but that “played” logic.

Jevons was fascinated with logic and reasoning. He believed you could start with one thing (a premise) and from this work through a chain of reasoning to the conclusion. He thought that this could be done for everything. This was based on a principle he espoused of “the substitution of similars”: essentially reasoning based on the idea that “Whatever is true of a thing is true of its like”,  For example, If Pharaohs are gods and Rameses is a Pharaoh (so is one of the things “like” a Pharaoh) then you can conclude Rameses is a god. He built on, and combined the ideas of, the Ancient Greeks with the then new ideas of George Boole, that we now call Boolean logic.

Boolean logic is based on a system of algebra using only the values of true and false (or 1 and 0), with operations corresponding to logical operations such as AND and OR that turn true/false values into new true/false values. This is the logic upon which computers are founded. A key idea was that you can abstract away from actual statements about truth in the real world and just replace them with variables that can stand for anything. Boole had laboriously shown using his logic how new abstract facts could be deduced from existing ones. Jevons realised that when reasoning was thought of like this, it became a mechanical process…and that meant a machine could do it.

His contemporary, Charles Babbage had been working on the idea of building mechanical “computers” but Babbage’s fundamental idea was that machines could do calculation. Jevon’s idea was slightly different and more fundamental: that machines could do logical reasoning, deducing new facts from existing ones. This was an idea that eventually came to fruition in the 20th century with the development of theorem provers where computers were programmed to do complex logical reasoning, even working on building up the whole of mathematics by proving ever more theorems from a few starting facts.

So, (with the help of an unknown craftsperson), Jevons set about designing and building his wooden Logic Piano. The idea was that you could put in the premises, the basic facts, by playing the keys of the “piano”. It would then mechanically apply his reasoning rules to discover all conclusions that could be deduced, altering its conclusion with each new fact added, The keys moved rods and levers that made logical facts appear on (or disappear from) the “display” of the machine – essentially facts on the rods appeared in slots cut into the back of the piano.

The kind of logical problem his machine worked with are Syllogisms (see Superhero Syllogisms). They were invented by the Ancient Greeks who were very good at logic. A syllogism is just a common pattern that combines facts where you figure out a conclusion only using the facts supplied, slotted into a template. For example, if we know facts 1 and 2 in the following template (where you can swap in anything for A, B and C) then we can create a new fact as shown.

FACT 1 ALL A B FACT 2 C is a A NEW FACT C B
Image by Paul Curzon

So let’s replace A with the word superheroes, B with fight crime and C with my favourite superhero, Ghost Girl. If we put them in to the template above we get a new “fact” deduced from two existing ones:

FACT 1 ALL super heroes fight crime FACT 2 Ghost girl is a super hero NEW FACT Ghost girl fights crime
Image by Paul Curzon
A set of 4 vertical rods with A B A ~B ~A B ~A ~B
Image by Paul Curzon

In the piano, a set of rods acted as truth tables, each one giving a true or false values for each variable. So imagine a piano that could deal with two variables A and B. Each of A and B can have two different values true and false, so there are four possibilities (so four rods):

  • (A, B);
  • (A, NOT B);
  • (NOT A, B);
  • (NOT A, NOT B)

where we write A to mean the assertion A is true and NOT A (or ~A in the picture) to mean A is false. Each rod represents a possible state of the world.

Let’s look at a simple example. Suppose A stands for the statement “Paul is a programmer” and B stands for “Safia is a programmer”, then the possibilities (if we know no specific facts) are

  • (Paul is a programmer, Safia is a programmer) : (A, B)
  • (Paul is a programmer, Safia is NOT a programmer) : (A, NOT B)
  • (Paul is NOT a programmer, Safia is a programmer) : (NOT A, B)
  • (Paul is NOT a programmer, Safia is NOT a programmer) : (NOT A, NOT B)
A set of 4 rods with bars that can hide the text if they are moved A B A ~B ~A B ~A ~B
Image by Paul Curzon

Each rod in Jevon’s piano had one of the possibilities on, so each rod represented a possible state of the world being reasoned about. At the start all the rods were visible, showing that nothing specific was yet known.

The point is that these represent all possible states of the world about Paul and Safia and whether they are programmers or not. If we know nothing more then all we can say is that all the pairs of facts are a possibility: all are possible states of the world.

The piano worked by essentially leaving displayed or hiding each rod’s state as new facts were keyed in. (See the video at the end which includes a detailed explanation by expert David E Dunning on the detail of how it did this step by step). Initially all the possibilities are displayed as above. If we add a new fact that we have discovered or wish to assume, say that “Safia IS a programmer” (in terms of the piano, press the B key corresponding to the fact B is true), then doing so removes all states of the world where Safia is NOT a programmer. The piano, therefore, hides all the rods that include the assertion representing “Safia is NOT a programmer” (all those with (NOT B) on them) . We are left with two alternatives:

second and fourth rod moved so hidden leaving A B ~A B
Image by Paul Curzon
  • (Paul is a programmer, Safia is a programmer) : (A, B)
  • (Paul is NOT a programmer, Safia is a programmer) : (NOT A, B)

The mechanics of the machine meant that those facts would remain a possibilities (reading down the rods) but pushing the keys for that assertion would have moved the other rods, so hide their state. In doing so, the piano has deduced from the fact B that the possible conclusions are A AND B is true or NOT A AND B is true.

With three variables instead of two the machine would be able to deal with more complex situations – there are then 8 possibilities so 8 rods representing the 8 different states. .

A set of 8 rods with A B C A B ~C A ~B C A ~B ~C ~A B C ~A B ~C ~A ~B C ~A ~B ~C
Image by Paul Curzon

Let A represent superheroes, (so NOT A represents those people who are not superheroes), B represents those people who fight crime and C with a person being Ghost Girl. Suppose we are considering some, at the moment, random person we know nothing about. The possibilities about them are:

  • (Is a superhero, does fight crime, is Ghost Girl) : (A, B, C)
  • (Is a superhero, does fight crime, is NOT Ghost Girl) : (A, B, NOT C)
  • (Is a superhero, does NOT fights crime, is Ghost Girl) : (A, NOT B, C)
  • (Is a superhero, does NOT fight crime, is NOT Ghost Girl) : (A, NOT B, NOT C)
  • (Is NOT a superhero, does fight crime, is Ghost Girl) : (NOT A, B, C)
  • (Is NOT a superhero, does fight crime, is NOT Ghost Girl) : (NOT A, B, NOT C)
  • (Is NOT a superhero, does NOT fights crime, is Ghost Girl) : (NOT A, NOT B, C)
  • (Is NOT a superhero, does NOT fight crime, is NOT Ghost Girl) : (NOT A, NOT B, NOT C)

If we put the fact about them into the piano that ALL superheroes fight crime (ALL A are B) then we remove all rods where A is true but B is different so false (a superhero who doesn’t fight crime) as in this world, that is impossible.

3rd and 4th rods hidden so leaving A B C A B ~C ~A B C ~A B ~C ~A ~B C ~A ~B ~C
Image by Paul Curzon
  • (Is a superhero, does fight crime, is Ghost Girl) : (A, B, C)
  • (Is a superhero, does fight crime, is NOT Ghost Girl) : (A, B, NOT C)
  • (Is NOT a superhero, does fight crime, is Ghost Girl) : (NOT A, B, C)
  • (Is NOT a superhero, does fight crime, is NOT Ghost Girl) : (NOT A, B, NOT C)
  • (Is NOT a superhero, does NOT fights crime, is Ghost Girl) : (NOT A, NOT B, C)
  • (Is NOT a superhero, does NOT fight crime, is NOT Ghost Girl) : (NOT A, NOT B, NOT C)

Then we add the fact that Ghost Girl is a superhero (C is a A) so remove all those rods where Ghost Girl is not a superhero (ie NOT A, C):

3rd 4th and 5th rods hidden so leaving A B C A B ~C ~A B ~C ~A ~B C ~A ~B ~C
Image by Paul Curzon
  • (Is a superhero, does fight crime, is Ghost Girl) : (A, B, C)
  • (Is a superhero, does fight crime, is NOT Ghost Girl) : (A, B, NOT C)
  • (Is NOT a superhero, does fight crime, is NOT Ghost Girl) : (NOT A, B, NOT C)
  • (Is NOT a superhero, does NOT fight crime, is NOT Ghost Girl) : (NOT A, NOT B, NOT C)

We have deduced (the first possible state) that if the person we are interested in is Ghost girl then she is a superhero. We are also left with other possibilities too. If the person we are considering is not actually Ghost Girl then they may or may not fight crime and may or may not be a superhero!

If we add in an additional fact that the person we are thinking of IS actually Ghost Girl then we remove those extra rods so possibilities and get

All but first rod hidden so leaving A B C
Image by Paul Curzon
  • (Is a superhero, does fight crime, is Ghost Girl) : (A, B, C)

Ghost Girl is a superhero who does fight crime! We knew she was Ghost Girl and was a superhero but using the piano we have now deduced that she does fight crime. The machine has deduced the syllogism we gave at the start.

IF ALL superheroes fight crime AND
   Ghost girl is a superhero
THEN
   Ghost girl fights crime.

The actual piano dealt with 4 variables (A, B, C, D) so had 16 rods representing the 16 different combinations. It also included keys to indicate the end of a conjecture, a key for IS A, and more to allow specific assertions to be input. The mechanism then hid rods automatically based on the facts entered. To use it, you did as we did: create a table of what A, B, C and D stand for (this is done outside the machine), enter the facts you want to reason about, and it then displayed all the possible states that remained in terms of A, B, C and D. Then, by seeing what each of the variables stood for in the table, you could convert that answer back into a deduced fact about the real world that you were interested in.

Amazingly, (after a first failed attempt) it did work. It is similar in idea to modern day theorem provers which are used to verify properties of safety-critical computer designs that must npot have bugs. Of course, being small and woody, the logic piano couldn’t solve every thing but then it turns out that was always an impossible dream. Even modern computers (and human mathematicians) have fundamental limits in what they can do (which is another story). The logic piano was a rather amazing, if woody, start to the area of automated theorem proving, though.

– Paul Curzon, Queen Mary University of London

Make a paper logic piano

Here is a kit to make a paper or card logic piano of your own (actually more like Jonons’ logic abacus the piano was a mechanised version of):

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A Purely Mechanical Form

A Talk by David E Dunning at the Imagining AI conference about William Stanley Jevons and the logic piano including at the end a more detailed explanation of how pressing keys actually caused rods to by hidden in a series of steps. See also his article about it for the Computer History Museum.

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