Charles Babbage is famous for his amazing technical skills in designing a computer, but also infamous for his apparent spiky and obsessive personality.
He certainly seems to have had poor social skills in that he often immensely irritated the people who funded his work. Part of the reason he never managed to complete a working version of his computer is that his funders pulled the plug on him. If only he had had better people skills to complement his technical skills and creativity, perhaps we would have had computers a century earlier! However, perhaps we should be less harsh. He wasn’t a total social misfit: his salons (Victorian high society parties) were extremely popular, and attended by what would now be considered celebrity A-listers. They often centred around demonstrations of science and engineering wonders, so presumably he could be the life and soul of the party… as long as he had a technological wonder to talk about. The young Ada Lovelace attended one such salon and was enthralled by his machines. Encouraged by her mathematically trained mother, Lady Byron, she studied maths and in 1840 collaborated with Babbage on a description of his Analytical Engine.
More to the point, if you consider the context of Babbage’s life, he suffered extremes of grief. In one year alone, 1827, he buried three of his children as well as his wife. Of his eight children only three survived beyond the age of ten. That was the brutal reality of the pre-antibiotic world.
In this context perhaps it is better to think about his work and achievements, as a response to adversity. That he achieved so much is a triumph of ambition over terrible loss.
Adrian Johnstone, Royal Holloway, University of LondonandPaul Curzon, Queen Mary University of London
Image of Tesla, Public domain, via Wikimedia Commons
Nikola Tesla is an enigma wrapped in a mystery. Not bad going for an electronic engineer. Born, so the stories go, in the middle of a thunderstorm in Serbia, Tesla has left a fascinating legacy to the world today. Magnetism is measured in Tesla, a unit named after him. But it is perhaps one victory we owe most to Tesla for. He fought a battle to show that alternating current (A/C) was superior to direct current (D/C) when it came to transmitting electricity over a distance. His opponent was none other than America’s most respected celebrity inventor, Thomas Edison.
Absolutely shocking behaviour
In the so called Battle of the Currents Tesla and his entrepreneurial partner George Westinghouse eventually won (they had maths on their side). If he hadn’t the world would have been filled with electrical substations at the end of each road, because D/C doesn’t do distance well.
Why is A/C better?
A/C is better for distributing power over a distance because it allows the easy changing of voltages using a transformer. Power is calculated as current times voltage (P = IV). For a given amount of power to be sent, a low voltage requires a higher current. But metal conducting wires have resistance. That means some of that precious power will be lost as heat in the wires. Theory (always important to know the theory) says that power loss is given by P = I²R. So from this its obvious that low-voltage, high-current transmissions will cause a much greater power loss than high-voltage, low-current ones. This fact holds whether D/C or A/C is used. But, and here is the clincher, transforming D/C power from one voltage to another is difficult and expensive. In Tesla’s day it needed a large spinning device called a rotary converter, and moving parts are always a problem. But with A/C these voltage changes can be done with simple and cheap transformer coils with no moving parts and no maintenance. Tesla wins in theory and in practice.
A Dirty Fight
Tesla ultimately won, but the fight was a really dirty one – there was ego and money at stake. Edison got his employees to badmouth A/C, to try and convince the public it was dangerous. They used A/C to execute stray cats and dogs to try to prove to the press that A/C was more dangerous than Edison’s system of D/C. They even filmed the A/C electrocution of Topsy, a circus elephant from Coney Island! Edison’s spin doctors also tried to popularise the term “Westinghoused” (the rival company to Edison’s that Tesla was working with) to mean being electrocuted. The battle cost an astronomical amount, and toward the end Tesla pulled out, tearing up the contract that could have made him the world’s first billionaire, and leaving Westinghouse to capitalise on the final victory.
Tesla retreated, and focussed on wireless control inventing the world’s first remote controlled boat, but he also had another card up his sleeve – he had invented the radio, and had the patent. But success was short lived. After a few years the US courts decided that Guglielmo Marconi was the inventor of radio and Tesla lost out again. In fact in 1909 Marconi was awarded the Nobel Prize for Physics for the invention of radio, and the rumour was that Tesla and Edison’s fight had lost them the chance of being included in the award.
Springing back into action
Never daunted, in 1899, Tesla moved to Colorado Springs, Colorado, where he could have enough room for his high-voltage, high-frequency experiments. He told reporters that he was conducting wireless telegraphy experiments, transmitting signals from a mountain called Pikes Peak in Colorado to Paris. He transmitted extremely low frequencies through the ground as well as between the earth’s surface and the ionosphere, and patented the ideas. He also calculated that the resonant frequency of the Earth was approximately 8 Hertz (Hz). Later in the 1950s, researchers confirmed that the resonant frequency of the Earth’s ionosphere was in this range, but chose to name it the Schumann resonance. Tesla was invisible again.
This is the end?
Tesla suffered from a lot of illness as a child and had a condition where he saw bright flashing lights and had visions and saw flashbacks. He was neurodiverse in that he had an eidetic (ie photographic) memory, able to remember pictures in great detail at a glance. He seems to have had an obsessive personality and may well have been on the autistic spectrum. On the whole he turned these things to his advantage leading to his great achievements: such as turning visions into inspiration for ideas and pushing on with ideas despite all the challenges he encountered through his life.
However, Tesla was no good with money. His genius and lifetime of invention led to him dying alone of heart failure, in a New York hotel room, impoverished at the age of 86. The story goes that the documents he had were seized by the American secret service under the direct orders of J Edgar Hoover. Tesla had been developing his radical ideas about transmitting power without wires through the earth over great distances. He called this a peace ray; it could manifest electrical power in mid-air wherever it was needed on the Earth. He also claimed to have worked out a ‘dynamic theory of gravity’ – even Einstein failed at this – but it was never published.
Tesla’s life has of course been the subject of movies; he most recently appeared in the film ‘The Prestige’, played by David Bowie: who else could play such an enigma.
Tesla is also featured on the bank notes of Serbia. So when you next plug in your mobile phone charger or use wifi, remember Tesla, the invisible genius who made it all possible.
Peter W. McOwan and Paul Curzon, Queen Mary University of London (From the archive)
Babbage’s wheel from a 3D model by Adrian Johnstone.
Charles Babbage famously designed the first computer: a steam powered contraption that was never built. At its core was something very simple and elegant: a cunning contraption that allowed his machines to store numbers and do arithmetic, all made of Victorian tech: metal wheels and levers.
Babbage had worked as a human computer, for example computing acturial tables that insurance companies use to help calculate risk or payments as well as for the Nautical Almanac used to navigate at sea. He realised that they were full of mistakes and that if a machine could do the computation mistakes could be eliminated. He set about designing and building machines to do that.
Babbage’s Analytical Engine, had it been built, would have been the first working general-purpose computer. The size of a factory, and powered by a steam engine, it was the ultimate cunning contraption. A giant whirring, clanking, puffing mechanical brain. Babbage’s first attempt at mechanical computation, though, was a simpler machine, the Difference Engine. It could only do a fixed, if very useful, kind of calculation. It computed what are called polynomials: patterns of additions and multiplications. It used a complicated adding mechanism. Later, whilst working on designs for his ambitious Analytical Engine he thought of a much simpler adder (described below). His second Difference Engine used this new adder and so needed about 16,000 fewer parts! The Science Museum built it in the twentieth century.
Representing Numbers
First he had to devise a way to represent numbers. Unlike modern computers which use binary, so only two digits, Babbage stuck to decimal. He was going to do all his calculations using our normal ten digits, 0 – 9. But how? His solution was to use metal cog-like wheels. His wheels had 40 teeth corresponding to the digits 0 to 9 repeated four times. To get the idea of how they worked, imagine a wheel with only 10 teeth, each with a digit 0-9 in order, next to a tooth. The wheel lays flat and one digit faces you. That digit is the number that the wheel represents. Turn it one place to the left and it represents one digit higher. Turn it a place to the right and it represents one digit lower.
That is fine for numbers between 0 and 9. For larger numbers, just do as we do: use the decimal place system where the value of a digit changes with its position. That first wheel is in the ones row so stands for 0-9. Put a wheel above it in a 10s row and it stands for 10 times the value shown. If a 5 is facing you on that wheel it stands for 50. You can now represent numbers 0 – 99. Put more wheels on top and you can represent hundreds, thousands, and so on.
It’s a neat way of representing numbers using the system we do (though our numbers run right to left not bottom to top). It makes it not only easy for a machine to manipulate the numbers by turning the wheels, but also easy for a human operator to read the numbers. His Difference Engine used several stacks of them, but Babbage envisaged a gigantic room-sized data store of column after column of these number wheels as the memory of his analytical engine, each column storing one potentially very large number.
A machine that can count
We now have a way to represent numbers but it isn’t yet enough to allow a machine to manipulate them automatically. As it stands it can’t even count properly. We have seen only how to count on one wheel, so only up to 9: every time we turn a crank the 1s wheel turns one notch and so the number represented moves on one. However, we need the other wheels to turn too, but only when the wheel below turns from a 9 to a 0 (so should really become 10). We need a mechanism to carry up to the wheel above. Babbage did this by adding a ridge (a ‘nib’) on the wheel that triggered the carry. When the wheel got to 0, the nib caught against a mechanism above and pushed it, before allowing it to spring back. That nudged the wheel above along one place as required. The 1s wheel was controlled by the crank. The 10s wheel was turned by the 1s wheel moving to 0. The 100s wheel was turned by the 10s wheel moving to 0, and so on. Babbage had a machine that could count!
A machine that can add
The next problem is how to add numbers stored on wheels. Imagine two wheels, interlocked by their teeth, When one is turned it turns the other the same amount. However if you lift one of the wheels they no longer interlock and move independently.
To do addition, the first wheel is used to hold the number to be added. The second holds the total so far: the answer. That answer wheel starts off set to 0. Now, with the wheels interlocked, turn the first wheel one position at a time counting up to the first number of the addition. It turns the answer wheel exactly the same number of positions transferring the number on to it.
Oops. When cogs interlock, the second wheel turns in the opposite direction to the first! Our machine is subtracting! To make it add, you need a connecting wheel between them. The middle wheel then turns backwards, turning the answer wheel forwards as required. With three wheels like this, any number on the first wheel is added to the answer wheel.
To add a second number, just lift the first wheel to disconnect it, spin it back to zero, drop it back in place and turn it to the second number. The answer wheel then holds the sum of both numbers. If you want to add more numbers, just keep doing this, loading one number at a time onto the first wheel. Each time the total passes 10, the carry mechanism passes the 10 onto the higher wheel and the full decimal total is stored up the stack of wheels.
We have a machine for doing addition!
A machine that can multiply
Babbage’s machines could multiply as well. How do you do multiplication on wheels? Well, multiplication is just repeated addition. If you want to work out 5 x 3, then it can be calculated as 5 + 5 + 5. So multiplication can simply be done using the adder, adding the same number over and over again. A counter keeps track of how many times to add it. There are faster ways to multiply though. For the Analytical Engine, Babbage designed an efficient table-based multiplier that he was justifiably very proud of.
Putting it together
Put this together and you have both a number store (a computer memory) and temporary storage areas (registers). You can transfer numbers from one place to another in the machine, and you have the basics of an arithmetic unit that can do calculations. That is about as far as Babbage managed to build. However, he also envisioned programs on punch cards that determined what instruction to execute, mechanisms that allowed instructions to make decisions, and to repeat instructions…everything needed for a general-purpose computer.
Sadly, only parts of his Analytical Engine were ever built, the Victorians did not start the digital age, and we had to wait nearly a century for the first working computers.
Paul Curzon, Queen Mary University of Londonand Adrian Johnstone, Royal Holloway, University of London
We have explained how core rope memory was used as the computer memory storing the Apollo guidance computer program that got us to the moon. A team from the University of Washington came up with a fun craft activity to make your own core memory. It may not fly you to the moon, but is a neat way to store information in a bracelet. Find their activity pages here [EXTERNAL].
What it involves is threading 8 beads onto a string, with a gap between them to form a storage space for bytes of data. Each byte is 8 binary bits (Eight pieces of information, each a 1 or a 0). Each bead represents the position of one bit in your core rope memory. You then take other threads and weave them through the beads. Each thread will store another byte of actual data. Pass the thread through a bead when you want that bead to read 1, or over, when you want that bead to read 0.
Each thread weaving past or through 8 beads can then encode the information for one letter. By adding lots of threads you can store a word or even a sentence on each core rope memory string (perhaps your name, or some secret message).
Using a binary encoding for each letter (so capital letter A would be the 8 bits 01000001 if you’re following this conversion from binary to letters table) you put that letter’s thread through or over each of the 8 beads to ‘spell’ out the letter in binary.
My name is Jo so a core rope memory encoding my name would have only three threads (one to hold the 8 beads and two to spell my name). The second thread would go over, through, over, over, through, over, through, over to spell the capital letter J (01001010). The second thread would go over, through, through, over, through, through, through, through to spell lowercase o (01101111).
Let’s hope you have a slightly longer name so can have more fun time creating your own personalised core rope memory!
Weaving, in the form of the Jacquard loom, with its swappable punch cards controlling the loom’s patterns inspired Charles Babbage. He intended to use the same kind of punch card to store programs in his Analytical Engine, which had it been built would have been the first computer. However, weaving had a much more direct use in computing history. Weaving helped get us to the Moon.
In the 1960s, NASA’s Apollo moon mission needed really dependable computers. It was vital that the programs wouldn’t be corrupted in space. The problem was solved using core rope memory.
Core rope memory was made of small ‘eyelets’ or beads of a metal called ferrite that can be magnetised and copper wire which was woven through some of the eyelets but not others. The ring-shaped magnets were known as magnetic cores. An electrical current passing through the wires made the whole thing work.
Representing binary
Both data and programs in computers are stored as binary: 1s and 0s. Those 1s and 0s can be represented by physical things in the world in lots of different ways. NASA used weaving. A wire that passed through an eyelet would be read as a binary 1 when the current was on but if it passed around the eyelet then it would be read as 0. This meant that a computer program, made up of sequences of 1s and 0s, could be permanently stored by the pattern that was woven. This gave read-only memory. Related techniques were used to create memory that the computer could change too, as the guidance computer needed both.
The memory was woven for NASA by women who were skilled textile workers. They worked in pairs using a special hollow needle to thread the copper wire through one magnetic core and then the other person would thread it back through a different one.
The program was first developed on a computer (the sort that took up a whole room back then) and then translated into instructions for a machine which told the weavers the correct positions for the wire threads. It was very difficult to undo a mistake so a great deal of care was taken to get things right the first time, especially as it could take up to two months to complete one block of memory. Some of the rope weavers were overseen by Margaret Hamilton, one of the women who developed the software used on board the spacecraft, and who went on to lead the Apollo software team.
The world’s first portable computer?
Several of these pre-programmed core rope memory units were combined and installed in the guidance computers of the Apollo mission spacecraft that had to fly astronauts safely to the Moon and back. NASA needed on-board guidance systems to control the spacecraft independently of Mission Control back on Earth. They needed something that didn’t take up too much room or weigh too much, that could survive the shaking and juddering of take-off and background radiation: core rope memory fitted the bill perfectly.
It packed a lot of information (well, not by modern standards! The guidance computer contained only around 70 kilobytes of memory) into a small space and was very robust as it could only break if a wire came loose or one of the ferrite eyelets was damaged (which didn’t happen). To make sure though, the guidance computer’s electronics were sealed from the atmosphere for extra protection. They survived and worked well, guiding the Landing Modules safely onto the Moon.
One small step for man perhaps, but the Moon landings were certainly a giant leap for computing.
Jo Brodie and Paul Curzon, Queen Mary University of London
People have always been fascinated by automata: robot-style contraptions allowing inanimate animal and human figures to move, long before computers could take the place of a brain.
Records show they were created in ancient Egypt, China, and Greece. In the renaissance Leonardo designed them for entertainment, and more recently magicians have bedazzled audiences with them.
The island of Rhodes was a centre for mechanical engineering in Ancient Greek times, and the Greeks were great inventors who loved automata. According to an Ode by Pindar the island was covered with automata:
Imagine swallowing a slug (hint not only a yucky thought but also not a good idea as it could kill you)…now imagine swallowing a slug-bot … also yucky but in the future it might save your life.
When people accidentally swallow solid objects that won’t pass through their digestive system, or are toxic, it can be a big problem. Once an object passes beyond your stomach it becomes hard to get at.
That is where the slug shaped robot comes in (watch the video below). The idea of scientists at the Chinese University of Hong Kong is that a robot like a slug could crawl down your throat to retrieve whatever you had swallowed.
If you think of robots as solid, hard things then that would be the last thing you might want to swallow (aside from an actual slug), and certainly not to catch the previous solid thing you swallowed. You may be right. However, that is where the soft slug-shaped robot comes in.
It is easy to make or buy slime-like “silly” putty. Add iron filings to slime putty and you can make it stretch and sway and even move around with magnets yourself. You can buy such magnetic slime at science museums…it is fun to play with though you definitely shouldn’t swallow it.
The scientists have taken that general idea though and using special materials created a similar highly controllable bot that can be moved around using a magnet-based control system. It is made of a special material that is magnetic and slime-like but coated in silicon dioxide to stop it being poisonous.
They have shown that they can control it to squeeze through narrow gaps and encircle small objects, carrying them away with it…essentially what would be needed to recover objects that have been swallowed.
It needs a lot more work to make sure it is safe to really be swallowed. Also to be a real autonomous robot it would need to have sensors included somehow, and be connected to some sort of intelligent system to automatically control its behaviour. However, with more research that all may become possible.
So in the future if you don’t fancy swallowing a slug-bot, you’d better be far more careful about what else you swallow first. Of course, if it turns out slug like robots can break down, so get stuck themselves, you may then be in a position of needing to swallow a bird-bot to catch the slug-bot. How absurd …
Computer scientist Jason Cordes tells us what it was like to work for NASA on the International Space Station during the time of Space Shuttle launches. (From the archive)
Working for a space agency is brilliant. When I was younger, I often looked up at the stars and wondered what was out there. I visited Johnson Space Center in Houston, Texas and told myself that I wanted to work there someday. After completing my college degree in computer science, I had the great fortune to be asked to work at NASA’s Johnson Space Center as well as Kennedy Space Center.
Johnson Space Center is the home of the Mission Control Center (MCC). This is where NASA engineers direct in-orbit flights and track the position of the International Space Station (ISS) and the Space Shuttle when it is in orbit. Kennedy Space Center, situated at Cape Canaveral, Florida, is where the Space Shuttle and most other space-bound vehicles are launched. Once they achieve orbit, control is handed over to Johnson Space Center in Houston, which is why when you hear astronauts calling Earth, they talk to “Houston”.
Space City
Houston is a very busy city and you get that feeling when you are at Johnson. There are people everywhere and the Space Center looks like a small city unto itself. While I was there I worked on the computer control system for the International Space Station. The part I worked on was a series of laptop-based displays designed to give astronauts on the station a real-time view of the state of everything, from oxygen levels to the location of the robotic arm.
The interesting thing about developing this type of software is realising that the program is basically sending and receiving telemetry (essentially a long list of numbers) to the hardware, where the hardware is the space station itself. Once you think of it like that, the sheer simplicity of what is being done is really surprising. I certainly expected something more complex. All of the telemetry comes in over a wire and the software has to keep track of what telemetry belongs to what component since different components all broadcast over the same wire. Essentially the program routes the data based on what component it comes from and acts as an interpreter that takes the numbers that the space station is feeding and converting them into a graphical format that the astronauts can understand. The coolest part of working in Houston was interacting with astronauts and getting their feedback on how the software should work. It’s like working with celebrities.
Wild times
While at Kennedy Space Center, I was tasked with working on the Shuttle Launch Control System for the next generation of shuttles. The software is very similar to that used to control the ISS. The thing I remember most about working there was the environment.
Kennedy Space Center is about as opposite as you can get from the big city feeling at Johnson. It’s situated on what is essentially swampland on the eastern coast of Florida. The main gates to Johnson are right on major streets within Houston, but at Kennedy the gate is on a major highway, and even then, travel to the actual buildings of the Space Center is a leisurely 30 minute drive through orange groves and trees as well as bypassing causeways and creeks. Along the way you might spot an eagle’s nest in one of the trees, or a manatee poking its head from the waters. Kennedy is in the middle of a wildlife preserve with alligators, manatees, raccoons and every other kind of critter you can imagine. In fact, I was prevented from going home one evening by a gator that decided to warm itself up by my car.
The coolest thing about working at NASA, and specifically Kennedy Space Center, was being able to watch shuttle launches from less than 10 miles away. It’s an incredible experience. The thundering engines vibrate throughout your body like being next to the speakers at an entirely too loud rock concert. Night launches were the most amazing, with the fire from the engines lighting up the sky. It is very amazing to watch this machine and realise that you are the one who wrote the computer program that set it in motion. I’ve worked in a few development firms, but few of them gave me as much emotion when I saw it in action as this did.
A replica of Beagle 2 in the Science Museum with solar panels deployed. Image by user:geni from Wikimedia CC BY-SA 4.0
A reason the Apollo Moon landings were manned was in-part because the astronauts were there to deal with things if they went wrong: landing on a planet or moon’s surface is perfectly possible to do automatically as long as things go to plan. It is when something unexpected happens that is always going to be the tricky bit.
Beagle 2 is a good example. It was a British-built space probe that was sent to explore Mars in 2003. Named after biologist Charles Darwin’s famous ship, Beagle 2, sadly it never made it. It was due to land on Christmas Day that year, but something went wrong and it vanished without a trace. Beagle 2’s disappearance was perhaps the inspiration behind the Guinevere One space probe in the 2005 Doctor Who episode ‘The Christmas Invasion’, but Beagle 2 was unlikely to have been stolen by the Sycorax.
Had Beagle 2 made it, the first thing we would have heard was its radio call sign, which was some digital music specially composed by Britpop group, Blur. It wasn’t the only part of the ill-fated Beagle 2 mission that had an artistic twist. Famous British artist Damien Hirst (the man who had previously pickled halved calves in formaldehyde tanks), had designed one of his famous spot paintings – rows of differently coloured spots – that was to be used as an instrument calibration chart. It would have been the first art on Mars, but it, instead, appeared to have become the first art all over Mars! However, if you shoot for the stars you have to expect things to fail sometimes. You learn and try again.
There was a twist to the story too, as eleven years later in 2015, the Beagle 2 was spotted by NASA’s Mars Reconnaissance Orbiter. Using sophisticated image reconstruction programs working with a series of different images, a picture of it was created that allowed the scientists to work out some of what had happened. It had landed successfully on Mars, but apparently its solar panels had then failed to fully open. One appeared to be blocking its communications antenna meaning it had no way to talk to Earth, and no way to repair itself either. It may well have collected data, but just couldn’t tell us about it (or play us some Blur). The data it collected (if it did) may be there, though, waiting for the day when it can be passed back to Earth.
While it may not have succeeded in helping us find out more about Mars, Beagle 2 has presumably become the first Martian Art Gallery, though, displaying the one and only work of art on the planet: a spot picture by Damien Hirst.
Peter W McOwan and Paul Curzon, Queen Mary University of London
The Apollo lunar modules that landed on the moon were guided by a complex mixture of computer program control and human control. Neil Armstrong and the other astronauts essentially operated an semi-automatic autopilot, switching on and off pre-programmed routines. One of the many problems the astronauts had to deal with was that the engines had to be shut down before the craft actually landed. Too soon and they would land too heavily with a crunch, too late and they could kick up the surface and the dust might cause the lunar module to explode. But how to know when?
They had ground sensing radar but would it be accurate enough? They needed to know when they were only feet above the surface. The solution was a cunning contraption: essentially a sensor button on the end of a long stick. These sensors dangled below each foot of the lunar module (see image). When they touched the surface the button pressed in, a light came on in the control panel and the astronaut knew to switch the engines off. Essentially, this sensor is the same as an epee: a fencing sword. In a fencing match the sword registers a hit on the opponent when the button on its tip is pressed against their body. Via a wire running down the sword and out behind the fencer, that switches on a light on the score board telling the referee who made the hit. So the Lunar Module effectively had a fencing bout with the moon…and won.
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