The plot thickens - it's always Christmas and never winter ...
Rudolf the Red, Part Four of the Trilogy All through the summer, I wondered and waited. Which of the rivals would seek my help this year - Sir Sangrathta Claus in his North Pole Industrial Complex, or the renegade Rudolf the Red, based in the Antarctic? In the past, I had aided each in turn against the other, maintaining a delicate balance of power between the two ancient enemies. Imagine my surprise when they both turned up at my lodgings! What could possibly have brought these two arch-rivals together? What external threat had induced Santa to climb into bed with a reindeer, so to speak? As they spoke, it all became clear. My Little Pony Incorporated had merged with the Company of Care Bears, and the resulting organisation was so large, even the annual Christmas consumer feeding frenzy wasn't enough for it. The "Our Littlecare Ponybear Corp" had devised a dastardly plot, and Rudolf and Sir Sangrathta sought my help to foil it. OLPC market research had determined that consumer spending slowed down in winter except of course at Christmas. The plot was simple, and almost the same as one devised by C S Lewis. OLPC would control the calendar, so that it was always Christmas and never winter. If you think about it, that's far worse than the opposite. "Ho ho ho", I said, sceptically. That's is so obviously impossible, I couldn't see why Rudy and Santa were worried, until they explained. OLPC had almost succeeded already. You may have noticed that Christmas seems to start round about September, and doesn't end until well into January. They were simply going to gradually extend it at both ends until it met sometime in May. Then it would always be Christmas. The other half of the plan was to eliminate Winter, and suddenly I realised that Global Warming wasn't an accident. But that left one problem. "Surely a world that is always Christmas and never winter would be ideal for you guys, too?" Rudy and Santa exchanged glances. Rudy spoke first. "No winter, no snow." he said, succinctly, and I could see what he meant. No snow, no sleighs; no sleighs, who needs reindeer? Then Santa explained why a 12-month Christmas was less than ideal. "The whole point of Christmas is that it's special. The little customers spend a month counting the days with their advent calendars, and on the day itself, it's like magic. And anyway, I need the other 12 months to recover. Christmas all year round means nervous breakdowns all round." So that was my commission. To boldly stop Christmas from spreading throughout the year, and to make sure that winter came. It was clear that such a gigantic undertaking could not be accomplished without help, so once again, I called on my friends, the squirrels. I had a plan. It is always best to aim at root causes, and the root cause of Christmas is television. You will have noticed that as the autumn progresses, the programs get more and more Christmassy; without this pull, Christmas just wouldn't happen. The other end of the problem was Global Warming, but I had a plan for that too, and that's where the squirrels came in. First, we tackled the television problem. It used to be really difficult to hack into a TV studio, on account of they didn't use computers. But now, satellite broadcasting has made things a lot easier. I'd better explain how this works. The programs are made on the ground - that's the easy part, because all you need are old Star Trek reruns, and the membership of a decent video club. They haven't got around to showing "I Love Lucy" yet, but its just a matter of time. You point a camera at all this, modulate a radio wave, and point the transmitter towards a satellite that you hang in the sky. To hang a satellite in the sky, all you have to do is use Arthur C Clarke's idea, and orbit your satellite at the distance where earth orbit takes 24 hours, which as I recall means 23,000 miles high. The satellite retransmits the signal in a directional beam, and anyone with a dish can pick it up. But the companies doing this, aren't simply public benefactors; they want to be paid for the service. So they encrypt the signal, to prevent people from getting a free ride, and sell the decryptors. There are several ways to get at this scheme. The first is to build your own decryptor, so that you can rip off the programs without paying for them. This really isn't worth doing; the effort of building a decryptor isn't worth the programs you get. More interesting is the idea of hitch hiking on to the beam going up. The satellite won't accept any old rubbish, of course. But it doesn't discriminate on the quality of the programs (as you can see). Instead, there is an authorisation code that it needs to receive, before it will accept anything for retransmission. And that code is encrypted before it is transmitted, just like Novell does with its passwords. And thus, breaking that code is made really, really difficult, as you can see the chaos that would be caused if any old bod could broadcast any old rubbish via satellite. So, I didn't even try to hack the password. Instead, I simply recorded the authorisation signals, and without even knowing what they were, I played them back. That gave me my way into the satellite, but next it was necessary to be a bit devious. I couldn't just override showings of "White Christmas" and the film whose name I forget, but is unbearably cute and has a Guardian Angel coming down to earth at Christmas or Wonderful Life, the one where James Stewart saves his Savings and Loan against the odds at Christmas (and I doubt if the US government enjoy watching that one, with what's going on in that industry), and all the other old pot boilers that they trot out each Christmas. Someone would have noticed. What I did was more subtle, and involved snow. The old IBM CGA card had a bug in it. To make video access really fast, you memory map it, so that writing to $B800:0 is writing to the top left hand corner of the screen. That means you have to use dual ported memory, so that it can be accessed by the CPU and by the 6845 video controller, and so that you can write it from the CPU, even while the 6845 is reading it. The bug in the IBM CGA is that if you do that, you get interference on the screen, which we call snow. You don't get that with Mono, EGA or VGA. But it means that if you want to do direct screen writes without any snow, you have to wait for the horizontal or vertical retrace, as the electron gun flies back for the next sweep, and you have to write your bytes out as it is retracing. Here's how you do this: retry: mov dx,3dah in al,dx test al,8 jnz doit test al,1 jnz retry l1: in al,dx test al,1 jz l1: doit: ;read or write to video memory TVs work in a very similar way to PC monitors; in fact, TVs were there first, so perhaps I should have put that the other way round. In fact, you can use an ordinary domestic TV as a PC monitor, provided it is a US standard (NSTC, short for Never the Same Colour Twice) TV, and not my dear old Baird. To do this, you have to use 40 column mode (try typing MODE CO40). This is why directory listings are designed for 40 columns. I still use MODE CO40 sometimes when I want to display something to a lot of people; a handy trick. So what I did was, whenever some horrendously cute program was scheduled about penguins in the Arctic, or Polar Bears in the Antarctic, or anything at all with Bing Crosby in it, or that James Stewart film, or The Snowman, or anything by Dickens - well, you see what I mean. What I did was, I beamed up authorised snow. As the films got more sentimental and Christmassy, my snow got more intense, with the result that everyone thought it was just interference (or cute), and changed channel to watch something more healthy, like Blue Peter, or the Texas Chainsaw Massacre. The non-satellite channels were easier, as there's no encrypting. The TV scans at 50 frames per second, so all I had to do was synchronise to that, and pump out a very brief microsecond blast of white noise every 20 milliseconds. Unfortunately, the PC timer ticks at a frequency of 18.2 times per second (it does an interrupt 8 each time), which is too slow. But there's more than one way to skin a cat; I set up a counting loop that just cycled as it counted down, and when it reached zero, it triggered the transmitter, and reset the counter, and that way, I could get close enough to 50 frames per second to simulate snow. And since I was pumping out noise not signal, I didn't need much power to do it. So, by gentle but insidious pressure, we delayed the onset of Christmas until the time when all channels were Christmassing full blast, at which point there was no way the thing could be delayed any more, but by that time, it was late November, and therefore officially Christmas anyway. Once I'd got this system working, I could leave it on automatic. The channels, bless them, published their schedules in advance, and Santa could spot anything remotely Christmassy at a hundred yards. So our PC-controlled transmitter sent up the authorisation recording and the snow, by consulting the system clock and Santa's schedules. That meant I could start to do something about it being Never Winter. There has been a lot of concern about the greenhouse effect. This is often cited, but never explained. Why should it be warmer inside a greenhouse than outside? The reason is the glass. The incoming heat comes from the suns rays, which are high frequency; light and infra-red, coming from a body whose surface temperature is 6000 degrees Celsius. These rays go through glass like , well, like through glass. So the heat can get into the greenhouse. This warms up the air and soil inside. But the temperature is only a few dozen degrees Celsius, and the radiation emitted by a body at that temperature is very long wave. Glass is opaque to radiation at that low frequency, and the heat can't escape by conduction (glass is a very poor conductor) or convection (because you keep the windows closed). Carbon dioxide has the same effect on radiation, so if there were to be more of it in the atmosphere, the world would be warmer. If you burn coal, oil or gas you convert carbon and oxygen to carbon dioxide. Some of that is dissolved in the oceans, some of it is grabbed by plants and photosynthesised into carbohydrates, but some of it remains in the atmosphere, and it could build up. Also, there's a bunch of guys chopping down trees as fast as their sharp little axes can chop, down in South America. Chop chop chop, and those trees are no longer photosynthesising. My first priority was to stop those choppers, and that's where the squirrels came in. If, when you square up to a tree and spit on your hands (which I am reliably informed is what all lumberjacks do) you see an unbearably cute little squirrel with bright eyes and a bushy tail sitting in the tree, there is no way you'll chop it down, because lumberjacks are gentle, sensitive souls, who drink tea and press wild flowers (which I also have on good authority). So while my squirrels held on in South America, I pursued my grand scheme. Reducing the level of carbon dioxide in the atmosphere is one way to cool down the globe. Another would be to turn down the wick in the sun, but a third way is to move further from the fire. Obviously, the scientists had already thought of this and rejected it. If you attach a rocket to the earth and light the blue touch paper, that won't move it at all, because although the rocket is pulling the right way, the rocket's exhaust is pushing the earth back the other. But if you harness up a team of reindeer, you don't have that problem, because reindeer don't work on the reaction principle (for an explanation of how they do work, see Connectivity December 1989). The first problem was that the earth is spinning, which meant that wherever we attached the tow bar, it would keep changing the direction of the tow. That's easily solved; you attach the towing point at the Pole. The choice of Pole was easy too; the South Pole is just ice on ocean, and we needed to attach to land. The real problem was that in Summer, if you tow the North Pole, you are moving it towards the sun, which is the wrong way. And not even reindeer are stupid enough to to a major exercise like that in winter. It looked like stalemate. Towing the South Pole would just lift a gigantic ice lolly out of the water, and towing the North sends you the wrong way. Fortunately, Angela, who has a reputation for unorthodox ideas, saw the answer. "You don't pull, you push". Brilliant. We needed a high tower to attach the lines to, so that the reindeer could tow downwards; fortunately, I spotted just the thing a few years ago in Paris, and when we went there, after a few inquiries, we were lucky enough to discover that they were selling it for scrap. So I bought the Eiffel Tower, and by attaching quite a lot of reindeer to it and sawing through the base, we got it aloft and northbound. Quite a lot of people turned out to see it go, waving their fists and shouting encouraging words like "arrettay-voo" and "Albion perfide". We got it back to the Pole, and set it up. We didn't need to put down foundations or anything like that, as the reindeer were going to be pushing it downwards. We attached lots of reindeer, and started them going. I expect you will by now have seen what the flaw in my plan was. I should have seen it too, because one of the courses I did at university was "Dynamics of an Asteroid", concerning just this sort of thing. But you don't tend to see the solar system as a rotating frame of reference. You'll be familiar with the gyroscope effect. If you take a rotating bicycle wheel and try to twist it, it feels like it is squirming through 90 degrees, and it doesn't wind up going where you pushed it. A planet rotating round its orbit is exactly the same, and when you push it one way, it moves at 90 degrees to your push. So that although the reindeer were pushing the planet away from the sun, the only effect was to tilt the orbit relative to the plane of the ecliptic. I've seen some pretty heroic cockups in my time. Everyone makes at least one mistake - IBM with the PC Junior, Microsoft with Dos 1.0, Lotus with Spotlight and John Logie Baird with the television. But not many people can sheepishly admit that they misplaced a planet. Well, of course, as soon as we realised what was happening, we shut down the reindeer, attached a ringbolt to the North Pole, and started towing in the same direction that the planet moves, with a component towards the sun to compensate for the earlier error. And pretty soon, we'd moved the world to where we wanted it. Winter had returned to the world, and Christmas only lasted for one month. I suppose you're all wondering what happened to the moon. Well, if I'd remembered Professor Moriarty's course, I would have remembered that the moon is actually more closely bound to the sun than to the earth, and in all that cavorting, we'd left it behind, still in its old orbit - conservation of momentum, don't you know. You've probably always taken the moon for granted, like I did; I never really thought that the absence of tides would be so important. But that turns out to be nothing, compared to the effect of having no moon on people, to to be more precise, on about half of them. OLPC are foiled, Santa and Rudy have settled their differences are are now working in partnership. But I'd better do something about the moon, before life gets completely unbearable. Maybe if I built a giant cannon out of say, oil piping, and aimed carefully ...
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