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The art of science

Yesterday I was writing a response to a entry by shesingsnow lamenting the deplorable run-time she was getting from her laptop battery and it became (again) really clear to me how much of an art Computer Science really is. Tweaking a laptop to get the most of its battery is an art. Getting wireless networks to run right certainly seems like an art -- and maybe a black art at that. Every situation, every building is unique, and the presence or absence of people (ugly bags of mostly water) can make a quantifiable difference in performance. E.G. an average size guy standing six feet away from me on the line from me to the AP will knock ~10 dB off the signal.

It seems that the old guild skill ratings -- novice, apprentice, journeyman, master -- are the most sensible ways to describe practitioners in IT. Going along with Computer Science as art, there certainly is a lot of deeply held superstition and myth. E.G. an oft-repeated but wrong idea is that the 2.4 GHz radio waves used by IEEE 802.11b/g wireless devices are absorbed by water. The frequency that's absorbed by water is a lot higher, and some who know this fact but not the next fact will use someone else's repeating of the water absorption myth as an excuse to ignore everything they say. The next fact is that, while 2.4 GHz radio waves are not absorbed by water, they do a very good job of yielding up their energy and exciting water molecules when they meet. This is why microwave ovens use this frequency range. This is also why masonry (which has a fair amount of water in it) will attenuate wireless signals more than sheetrock, and why a potted plant or a human body acts like a wireless sponge.

Of course this is all bunk. It is a science. All of the hardware operates in according to scientific laws. It's all created by human engineers; it is all understandable, measurable and knowable. Unfortunately the knowledge space is almost incomprehensibly vast. There is so much to know -- and much of it takes specialized instruments to know -- that the practitioner in the field is left to fend for himself with a thimble-full of knowledge. IMO, that's why a packet sniffer is such a powerful tool: it shows you, with certainty, everything on a given network connection. No guessing; either a packet is there or it's not.

But, how many of us have sniffers? And, how many of us know how to use them? In our organization the answer is two and two, one a journeyman, the other master. So, I suppose that under these conditions -- a nearly infinite knowledge space, minimal tools and limited training -- it probably is safest to treat the science as an art. Knowledge, amplified by instinct and logic, applied successfully make the master from the apprentice.


( 9 comments — Leave a comment )
Oct. 10th, 2004 01:05 pm (UTC)
Hey, can you packet sniff the nuns? You know, see what they're *really* sending out into the world?

(okay, I thought it was a funny question even if it doesn't make any sense. But for one would love to know if the nuns will pick up on the wireless network in their area.)
Oct. 10th, 2004 01:31 pm (UTC)
Um, well, if the nuns have Ethernet connections... Oh, I see, you're thinking of the Catholic book store across the street. Yes, if they're on our wireless network then there's a spot where I can stick a sniffer and catch anything they send or receive. Presuming, of course, that we're not dealing with CryptoNuns.
Oct. 10th, 2004 01:32 pm (UTC)
LOL You never know what they have tucked away there in the back depths of that store - or what they are running...
Oct. 10th, 2004 03:03 pm (UTC)
Seems like a perfectly good base of operations for a group of vampire hunters.

Actually, most of the building is occupied by Catholic Family Charities, specifically their migrant and refugee services. Which again, would be a fine cover for vampire hunters. Hmmm.
Oct. 10th, 2004 03:17 pm (UTC)
*That* sounds like a job for HOPS. CryptoNuns indeed.
Oct. 10th, 2004 01:06 pm (UTC)
it probably is safest to treat the science as an art

And thus alchemy lives. Natural philosophy, even.
Oct. 10th, 2004 02:25 pm (UTC)
I agree that learn-by-doing-with-mentoring is still the best, if not the only, way to really understand how all this stuff works and fits together.

On the 802.11 stuff: at a USENIX conference some years ago in San Diego, I got better performance from the wireless network by going to my room in the 6th floor of the hotel.

My room overlooked the meeting rooms building, and worked much better than sitting in the lobby of the meeting room during the breaks. The sheer mass of humanity moving past killed the signal, while the longer-distance but almost totally open-air shot to the hotel room was always nice and strong.
Oct. 10th, 2004 03:07 pm (UTC)
In the world of wireless, that makes perfect sense. :-)

I recall reading one of those exasperated "oh for the love of God people, wake up!" articles about wireless security that used a recent USENIX conference as its example -- the author was describing the number of sysadmins who would telnet into their work/school systems, sometimes su'ing to root, over USENIX's open wireless network. I believe the author went on to say that a group was there running AirSnort and posting lists of hosts and root passwords in order to drive their point home...
Oct. 10th, 2004 04:07 pm (UTC)
Oh, yeah, the San Diego conference was the same one that featured a WIP session titled Interesting passwords found on a wireless network. Dug Song was demonstrating all the dsniff tools, including the cute and very demo-riffic one that would sniff URLs, eliminate the ones for embedded images and the like, and feed the page URLs to Netscape so your browser would "mirror" your target's web surfing.

Me, I like EtherPEG. See also the amusing O'Reilly Network article on it.

Heck, ten years ago at USENIX I was using a minimum of one-time passwords when I didn't have a laptop available, or crypto if I did. (Of course, back then single DES was at least vaguely respectable rather than the total joke it's since become.)
( 9 comments — Leave a comment )

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