Wednesday 25 December 2013

Rudolf the Red, Part Four of the Trilogy

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

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

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

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

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

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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