Kozue rests at the corner of the swimming pool, out in the midst of campus. The afternoon sun is giving her a good suntan as she browses away on her new, waterproofed laptop. (It runs Scientific Finux.) She is just passing the time until her next math class. Browsing the sites - like which eyeliner can complement the blue, or what the men really
do behind the closed doors. Doesn't everyone? It isn't you-know-what, obviously.
Unbeknownst to Kozue, behind a nearby tree, Mitsuru struggles holding out the TV antenna. Said antenna is hooked up to Nanami's portable TV- where Nanami eagerly peers at the grey static that isn't supposed to be there. She's trying out this one thing she's read; Van Eck Phreaking. (Spying, getting the latest scoop with the latest means.) Mitsuru's antenna can read the electromagnetic waves radiating out of Kozue's laptop circuitry at all times. But the laptop is sold as a computer usually, not as some radio station and so it might seem odd to you that it should be radiating anything at all.
But wait, let's back things up a bit. If you lay a sheet of white paper on an old gravestone, and sweep the tip of a pencil across it, you get one horizontal line, dark in some places, and faint in others, and not very meaningful. If you move downwards on the page by a small distance, a single pencil-line-width and repeat, an image begins to emerge. The process of working your way down the page in a series of horizontal sweeps is what a smart-aleck computer nerd would call raster-scanning, or just rastering. With a conventional video monitor (a cathode-ray tube), the electron beam physically rasters down the glass something like sixty to eighty-five times a second.
In the case of Kozue's flat laptop screen, there is no physical scanning; the individual pixels are turned off or on directly. But still a scanning process is taking place; what's being scanned and made manifest on the screen is a region of the computer's memory called the video buffer. The contents of the video buffer have to be slapped up upon the screen sixty to eighty-five times per second. Or else the screen will flicker, likely give you a seizure, and the images will move like a badly animated cartoon.
The way the computer talks to you is not by controlling the screen directly, but rather by manipulating the bits contained in that buffer, secure in the knowledge that other subsystems inside the machine handle the work of pipelining that information onto the actual, physical screen. Sixty to eighty-five times a second, the video system goes "Frak!" time to refresh the screen again, and goes on to the beginning of the video buffer (which is just a hunk of video memory, remember.) and it reads the first few bytes, which dictate what color the pixel in the upper left-hand corner of the screen is supposed to be. This info is sent on down the line to whatever is actually refreshing the screen, whether its a scanning electron beam or some laptop-style system for directly controlling the pixels. Then the next few bytes are read, typically for the pixel just to the right of that first one, and so on all the way to the right edge of the screen. That draws the first-line of the grave-rubbing.
Since the right edge of the screen has not been reached, there are no more pixels off in that direction. It is implicit that the next bytes read from memory will be for the left-most pixel in the second raster-line down from the top. If this is a cathode-ray tube kind of screen, we have a little timing problem here in that the electron beam is currently at the right edge of the screen and now it's being asked to draw a pixel at the left edge. It has to move back. This takes a little while - not long, but much longer than the interval of time between drawing two pixels that are cheek-by-jowl.
This pause is called the horizontal trace interval. Another one will occur at the end of every other line until the rastering has proceeded down to the last pixel at the bottom right hand corner of the screen and completed a single grave-rubbing. But then, it's time to begin the process all over again, and so the electron beam (if there is one) has to jump diagonally all the way up to the upper left-hand pixel. This also takes a little while and is called the vertical retrace interval.
These issues all stem from inherent physical limitations of sweeping electron beams through space in a cathode-ray tube, and basically disappear in the case of a laptop screen like the one Kozue's looking at - and she is now done reading Ladies' Nightly by the way. But the video timing of a laptop screen is still patterned after that of a cathode-ray tube screen anyway. (This is simply because the old technology is universally understood by those who need to understand it, and it works well, and all kinds of electronic and software crap has been built and tested to work within that framework, and why mess with success? Especially when the inconvenience is so small that it can only be detected by using techniques from quantum mechanics and any glitches vis-a-vis compatibility with old stuff will send the technological world straight to hell.)
On Kozue's laptop, each second of time is divided into 75 perfectly regular slices, during which a full grave-rubbing is performed followed by a vertical retrace interval. Nanami can follow "Cryptonomicon" well enough to gather that, analyzing the signals coming into the antenna, that Kozue has her screen set up to give her 600 lines, and 800 pixels on each line. For every pixel around two bytes will be read from the video buffer and sent on down the line to the screen.
Nanami has set up the antenna so that it can read the electromagnetic waves radiating out of Kozue's computer circuitry at all times, instead of Sakura-TV and Nippon Central Inc. stations from many miles away. Kozue's laptop is sold as a computer where she got it from, not some damned radio station, and so it might seem odd that ze laptop should be radiating anything at all. It's all a byproduct of the fact that computers are binary critters, which means that all chip-to-chip, subsystem-to-subsystem communication taking place inside the machine - everything moving down those flat ribbons of wire, and the little metallic traces on the circuit boards - consists of transitions from binary ones to zeros and back again.
Consequently in these transitions, electromagnetic waves propagate out into space as by-products; much like how CO 2
and bad methane gas are byproducts of heavy industry. Didn't Greenpeace make the world a healthier place to live in yet? But neither Nanami, nor the other fellows running around Ohtori Academy would have likely heard of such an organization, oh well.
The signals that the laptop broadcasts are completely dependent upon the details of what's going on inside the machine. Since there are a lotsa wires in where and the particulars of what they are doing are fairly unpredictable, it's difficult for anyone monitoring the transmissions to make heads or tails of them. A great deal of what comes out of ze maschine is completely irrelevant from a surveillance point of view. But there is one pattern of signals that is:
a. Totally Predictable
b. Exactly what Nanami wants to see
and that is the stream of bytes being read from the video buffer and sent down the wires to the screen hardware. Amid all the random noise coming from Ze Maschine(R), the ticks of the horizontal and vertical retrace intervals will stand out as clearly as a guy in the Lillian Girls' Academy. And now that Nanami has zoomed in on that creepy-looking guy with black trenchcoat and neko-glasses, she should be able to pick up the radiation emanating from the wire that connects screen buffer to video hardware, and translate it back into a sequence of ones and zeros that can be dumped out onto their own screen. Nanami will be able to see what Kozue sees, through the kind of smart surveillance called Van Eck phreaking.
That's what Nanami knows.
"You got it?" Mitsuru asks, as he does a balancing act with the antenna on his nose.
A faint picture comes up on the portable TV screen, and Nanami can make out something - Kozue is rummaging through folders on her hard drive. Schoolwork, fanfics, pics..
"Yes!" Nanami squeaks in sheer delight. "Now stay that way, Mitsy! Don't you dare move..!"
Pics.. what might be in that folder? The Christmas party, oh Nanami recalls like it is yesterday, when Anthy got her dress spilled with staining champagne. Hahaha. And Utena shewed up like a prince to rescue-
Where is Kozue's mouse clicking? Folder "asdf."
And she is going through some .jpg files - named by dates.. (what do they have what do they have?)
Kozue starts a slide-show of these files..
Hmm, there's Kozue, Miki, pink-haired Utena and Anthy, sitting at the dinner table. A giant roast chicken, BBQ sauce and stuff as the main course. Nanami's mouth is watering at the sight, even though the ham sandwich she had some minutes ago is still settling itself in her fat gut. And more pics of the four, smiling, taking poses. That's nothing special. Next!
WHAT A HELL?~~!
"Nanami?" Mitsuru says, looking pensively at his mistress. Nanami does not look good, her mouth is gaped open and her eyes are dancing the Cha-Cha 10,000 miles away. "What is it?"
"Utena- Ut- Koz- Ute-" Nanami's blubbers come out incomprehensible, and her cheeks are blushing so red- oh god, she is going to explode. "Oh my.. oh my.."
At the pool, blissfully unaware that her privacy has already been invaded, Kozue blushes too.
Then the school bell chimes, and Kozue takes a step out the pool, her sweet self dripping wet, and packs up her laptop, without so much as glancing at the Spying Inc. tree. When Nanami is sure the coast is clear, she half-stumbles to get her portable TV.
"What'd you see?" Mitsuru goes. "Nanami?" He tries shaking her by the arm.
"Ermm.. Um.. Ahh.. Pics.. of Kozue.. and Utena.. having chicken," Nanami tries to explain. "Yeah! Hot steamy chicken."
As Nanami heads on over to gym class, in her head, she is figuring out ways to blackmail Kozue in the case anything goes terribly wrong later. Sometimes, it pays to learn to be smart geek. Sometimes.
edited 12th Feb '11 11:06:56 PM by QQQQQ