One day I came home to find that one of the bushes at the end of my driveway looked funny. Almost as if its color had turned more pale. When the light caught it, it looked like it was shiny too. So once I parked, I had a closer look. The entire bush was covered with silk. That was odd. So I kept examining it, and then realized it also contained a huge hornet nest approximately the size of a basketball. But there were no hornets around. The nest was empty. Then I understood what had probably happened. Some spider had found the bush, set up a web, and caught a hornet. So she stayed there, nabbing hornet after hornet, having plenty of nice meals. And, like tribbles, if you feed a spider, you get more spiders. I'm guessing that some of her family hung around and also set up shop, enjoying the constant stream of food, eventually covering the entire bush with their webs. As more and more spiders accumulated, the process would accelerate, the hornets being consumed faster and faster.

Somehow I had missed the entire process, only to happen upon an abandoned nest and a bunch of webbing. As spider webs are somewhat ephemeral, I suspect they had just finished eating all the hornets, and moved on when the food supply ran out. Thanks, spiders!

When I was in high school, I'd write silly programs that would attempt to do crude animations by playing with the text characters on the screens. There was one that drew a "diving board" made of underscores, and the cursor would bounce up and down on it, and then fall through. Another made a boxy plane, labeled "747", shudder across the screen. All of these were available to the other students using the county's computer system. And all of them would proudly proclaim that they had been written by me.

A few years later, I was signing up for classes, and the woman at the registration desk paused in her task of busily keying in my information. She looked up at me, and asked "Are you THE John Rehwinkel?" This caught me off guard, as I was unaware of being famous at all, or anyone else with my name for that matter. So I asked her what she meant, and she explained that she remembered the name from the silly animations she'd seen on the computer at high school. It was a good feeling.

My good friend [profile] maugorn would occasionally find himself confronted with some loser having a bad drug trip. So he'd offer them some "help". In a soothing voice, he'd start saying calming things:

Imagine you're in a pleasant meadow, the wind gently rippling the grass, the sun warm on your face. In the distance, you see a letter A. The letter A comes toward you (at this point, his voice would start to get louder and scarier). The A opens its mouth and it SHOWS YOU ITS SIX INCH LONG RAZOR SHARP STEEL FANGS!

When I was a kid, I didn't have a particularly good sense of balance, so I fell down a lot. Due to this, I got pretty good at controlling my falls so I didn't get injured. We went on a class trip to the state house, which has a sweeping spiral marble staircase. Sure enough, I slipped (with a little help from some bully) near the top. After a few stairs, I realized I had a choice. I could stop tumbling, or I could keep going. I figured it would be more impressive if I kept going. So I flailed down all three flights, ending up in a tangle of arms and legs at the bottom. The bully actually looked somewhat contrite.

Years later, in college, I was coming in out of the rain into a large lecture hall. Sure enough, I slipped on the stairs. Again, I figured I'd just go with it, and tumbled all they down, stopping when I got to the lectern. Whereupon I stood up, took a bow to scattered applause, and went to my seat.

When I had my first computer capable of video games, an Atari 800, I wrote a very simple game, which I dubbed "Kill the Cities". It laid out a three by three arrangement of red and green rectangles, which were the cities. To destroy a city, you had to shoot it. The cities were in plain view, did not move, did not have shields, and did not shoot back. You had unlimited shots. The only tricky part was the aiming cursor code was rudimentary, and erased anything under it. So if you took your time and scrubbed over a city, you could eventually render it invisible. Given this immense degree of difficulty, if you somehow managed to destroy all nine cities, the game would produce a hissing sound, and the text:

You win! You hear that? They're cheering for you!

This was actually one of my more popular games.

I was working on a play once, and the director needed to thread a rope through the hem of a huge scrim, maybe 30 meters across. He had tied a knot in the end of the rope, and was coaxing it along, a bit at a time, by squishing it through the fabric. A very slow and frustrating endeavor. Then he spied me watching, and said "hey, you don't look busy, you can thread this rope!"

So I pulled the rope back out, which rather boggled and distressed him, then grabbed a broomstick and tied the rope through the hole in it. Then I arranged the rope for easy unwinding without tangling, put the end of the broomstick into the hem, got all lined up, and then pitched the broomstick down the hem, javelin style. It made it most of the way to the other end in one go, and then I could scrunch and pull the broomstick almost a meter at a time, getting it out the other end in just a couple of operations.

The look on the director's face was priceless. On the one hand, he was thrilled the wretched job was done. On the other hand, I had utterly shown him up.

A while back, my company was subcontracting to another company on a government contract. One day they called in a panic, saying the system wasn't working and I had to drop everything and get out there NOW. It was a couple of hours through DC Beltway traffic to get there, so I wasn't enthusiastic, but I didn't really have a choice.

So I showed up, found the guys with the problem, and they sat me down at a computer. This was running their test version of the system without our debug passwords installed. So I asked for the system password, only to be told it would take a couple of hours to find out whether I was even allowed to have it. "Ah, got it!", I crowed, hammering the keyboard like a maniac. "What's the database password?" Again, they said it would be a while before I could get that. A few seconds later, I chirped "Ah, I figured it out" and kept going. "What's your encryption key?" And so forth.

It turned out the problem was that the software, just sitting there doing nothing, would absorb 72 database connections, and each user session took six more. It didn't take many users before they'd hit the limit of 100 simultaneous connections. They asked me how to fix it, and I explained that they had two choices - rewrite the software to not be so profligate with database connections, or increase the number of allowed simultaneous connections. "How do we do that?", they bleated. I explained that the proper way to increase the number of database connections was to write a large check to the database vendor. They didn't like either answer.

I later heard that their security manager had been aghast at my "hacking" their system to obtain the passwords needed to do the job they insisted I come do instantly, and I was no longer allowed in their data center. Which was fine with me.

When I was studying computers in school, the early courses were packed, and used as weed-out courses to reduce the student load in the higher courses to a smaller set of theoretically more appropriate students. However, I took issue with the courses that weeded people out by being taught poorly. Since there was no mechanism to test out of these, I had to go and take them too, even though I pretty much knew all the material.

I noticed that the lecture hall for my ForTran class was vacant after the class ended, so I'd stick around, and re-teach each day's lesson in my style to whoever felt like hanging around. I got a huge benefit from this, as teaching something is a great way to find out what I really understood and where I was on thin ice. The stuff I realized I didn't quite get either, we'd work through together. A win all around.

When I attended the University of Maryland, our computer science courses were taught using a Univac 1104, fed batch-mode by punch cards. There was a room available with IBM Model 29 keypunches modified to produce the Fieldata format used by the Univac, but there weren't enough of them, so there was always a wait to use a keypunch machine. However, for last-minute quick fixes, there was one "express" machine, for five cards or less. There was always a line for it too, which moved slowly as people would hunt and peck in slow motion, then reject the card and start over. People would take ten minutes to punch a few cards!

So I acquired the habit of just going to the front of the line, and keying peoples' cards for them. I could blast through the entire line in a few minutes. As I was doing so, I'd point out errors for people, to save them the time of waiting in line again, or worse yet, submitting their botched job and waiting a couple of hours for it to fun.

Happily, people rapidly got used to my habit, and realized I really wasn't going to try to steal their homework.

This is another story about my dad.

Some people were having trouble with an earth observation satellite. This particular one had a clever scanning system that used the satellite's own motion for one axis, and a pivoting mirror for the other. The problem was, as time went by, the mirror wasn't able to swing as far, so the swathe the satellite could observe would slowly get narrower and narrower.

Nobody really understood why this was happening, or how to deal with it. Eventually, they asked my dad to look at the problem. His approach was to get copies of all the engineering drawings and then ponder them, which he did for a couple of weeks. He eventually formed a logical hypothesis of why the mirror might be getting restricted. The mechanism that moved the mirror involved a collar that slide along a greased rod. My dad's idea was that the grease was getting thick after being in the vacuum of space for a while, and piling up on the ends of the rod, where it would get in the way. Better yet, he had an idea to fix this.

The procedure for putting the satellite into idle mode while it passed around the night side of the earth was to center the mirror. My dad's idea was to modify this procedure and instead rotate the mirror as far as it would go to one side and let it sit there overnight. This, he figured, would tend to slowly squish the grease out of the way. The next night, park it at the other side, alternately pushing the grease away at both ends.

This made sense to the people in charge, seemed harmless, and might work, so they approved the change in procedure. And sure enough, as the weeks went by, the mirror slowly increased its range of motion, and ultimately was capable of its full original scan.

So, from thousands of miles away, without even seeing or touching the satellite, my dad was able to repair it (and avoid the same problem in future satellites), by making a simple change in a procedure. All from looking at the design documents and thinking about it. Good on ya, dad.

This is a guest story, one of my dad's.

My dad was working on a problem with a satellite. Like most satellites, it was a complicated, expensive affair, but this particular model didn't last as long as it was supposed to, and my dad was asked to analyze the problem and suggest possible solutions.

The satellites generally failed when a particular optical encoder would stop working. This consisted of a light bulb, a slotted disc, and a light sensor. As the disc rotated, the sensor would see the light get brighter and dimmer as it passed through the slots. The problem was, this type of bulb had a filament that would evaporate, causing the glass to silver, blocking the light. There was an established procedure to deal with this when the light output got too low. They'd crank up the voltage to the bulb, which would then emit more light. Unfortunately, it would also evaporate faster, and they'd have to crank it up again. After a few cycles of this, the bulb would burn out and then the satellite didn't work any more.

My dad made a simple suggestion - add a second bulb. He was told that this would involve too much re-engineering, making a second hole in the casting to hold the bulb, switching circuitry and another driver transistor for the additional bulb, so the whole circuit board would have to be laid out again. Too much to design, test, and get approved before the next launch.

So my dad went and pulled the engineering drawings for the satellite. Lo and behold, there already was a second hole in the casting, in just the right place. And there was switching circuitry and a place for an extra driver transistor on the circuit board! A few phone calls confirmed that the original design had called for a second bulb, but it had been deleted for cost reasons.

Armed with this information, he was quickly able to get the second bulb approved and installed in time for the launch, effectively doubling the life of the satellites.

When I worked at the particle beam lab, we had a large electron injector about the size and weight of a locomotive. It had a large Marx high voltage generator in the back, which lived in a dumpster-sized tank of high voltage transformer oil, open on top. In order to position it for various experiments, it could be floated on air pads pressurized by compressed air, and pushed around by hydraulic cylinders.

One day, the hydraulic system failed, but it needed to be moved. The researcher figured we could fire up the air pads, making it essentially frictionless, and round up some physics grad students to simply push it into position.

We got everybody lined up along the back of the thing, turned on the air pads, and we started pushing. It didn't seem to budge, as it was quite heavy, so everybody kept pushing, not realizing that we were continuing to accelerate this huge mass (it's physics!). After a while, its motion was perceptible, so we stopped pushing. It crept across the equipment bay at a stately pace, until it hit the stops and ... stopped. The thousands of gallons of transformer oil, however, didn't. In a giant, slow motion slosh, the transformer oil started to pour over the front. Then it got sucked into the air pads, became atomized, and formed a thin, strange-smelling fog and making everything slippery.

That's when folks suddenly remembered that the exotic high voltage transformer oil was distinctly unhealthy, as well as capable of dissolving all sorts of rubber and plastic compounds - such as the soles of our shoes. We all got out of there, massively chagrined.

Like many programmers, when I'm developing code, I'll put in amusing error messages for when the code does something I don't expect. However, sometimes this code will get shipped before it's ready. Which leads to querulous calls from the customers. We've had the United States Navy ask us about some of these, which must have caused some consternation out at sea when they popped up. Seriously, folks, ASK me before you ship my software!

One time, I was writing a driver while the hardware engineer (his nickname was "Hoppy") was simultaneously debugging the hardware. I kept getting a particular error condition, only to find out it was because Hoppy had been screwing with something. After a few iterations of this, I simply put a printout at that point in the code that said "Hoppy's playing with the wires!" Sure enough, I forgot to remove it, and that message popped up in the field.

"Shut 'er down, Slim, she's sucking mud!" (a favourite of my friend, Ron Eirtle)

And my personal favourite: "I can't get a buffer to save my ass!"

I've long had a habit of naming computers I administrate after women I know. Once upon a time, the company I worked for decided to put us in our own division, "Telos Information Technologies". Yup, my servers were then named things like,, etc. That didn't last long.
We were getting ready for a fancy demo to a customer, including showing off our fancy new parallel data link. But, at the last minute, one of the wires came loose, so when we sent "Hello, world!" across it, it arrived at the other end as "Jello, world!"
Once, when we were working on a hardware proposal, one of my co-workers came to me with a piece of paper with "Onkyo" written on it. He asked me what I thought of that manufacturer. Thinking it was related to our proposal, I offhandedly said "they make consumer-grade stereo gear", with my tone of voice making it clear that I meant this derisively.

Later I found out that he'd just spent a few thousand dollars on an Onkyo stereo system, and he wanted my real opinion on his purchase. Unfortunately for him, he got it.

I normally got poor grades in school, mostly because I couldn't be bothered to do homework. One day, in calculus class, the teacher decided to taunt the class by announcing "I will award a grade no less than one letter grade below what you get on the final exam." At first, he enjoyed the expected groaning and grimaces, until he saw me grinning madly and realized he'd made a tactical error. He and I both knew I would ace the final, and now he'd just promised me a B for doing it, even if I didn't do anything else for the rest of the semester!

The final was tough, and I did ace it. There was one final question that was this big scary horrible-looking integral that refused to yield to any of the usual techniques for simplification. I refuse to be scared off by marks on paper, and I figured I had plenty of time and nothing better to do. So I dove in and integrated the mess. And sure enough, the whole thing fell apart in the process, leaving the final answer to be something trivial like "2". It turns out the star pupils both were too frightened by the monster equation and didn't even attempt it!

When I was working at the particle beam lab at the University of Maryland, I learned not to say whether I knew how to do something, just assume that I could learn how. One of the researchers asked me to create a high voltage pulser with a high voltage output with a very short risetime (less than a nanosecond).

This was a tall order, so I went to hit the books. It turned out that there was a special tube designed for just such a purpose, known as a krytron. This was an obscure beast, which actually used radioactive nickel to keep the gas in the tube partially ionized, ready to switch at any moment. It had originally been designed for firing explosives in nuclear weapons, and had been classified. But this was an advanced lab and had accumulated a great assortment of oddball parts. Some time spent asking questions and rummaging around actually managed to produce a krytron.

This was a little thing, about the size of a peanut. I built a charged transmission line setup, with the tube switching it into a 50 ohm load, and ran the thing at a few thousand pulses a second with a sampling plugin to an oscilloscope to fine-tune it and measure the actual risetime (which turned out to be an astonishing 370 picoseconds or so).

So I went to show the finished apparatus to the researcher, only to find out he had basically given me the assignment as a prank, figuring a young college student who wasn't even in his research program wouldn't be able to solve such a difficult and arcane problem. He'd also given it to one of his EE grad students, who'd assembled this huge board with a chain of "avalanche" transistors in series to do the switching. It took about ten minutes between pulses, and would fry the transistors every dozen cycles or so. My board had run for hours at thousands of pulses per second, and was still on the original tube.

My mom was going back to school to prepare to re-enter the workforce, and we ended up deciding to take the same math class. After a few weeks, the teacher called us both in. She explained that she was a little curious how we did things. We always sat together, and had the same surname, and when she'd hand out a test, she'd get back a lot of copies of essentially the approach she'd just taught, and two oddballs, from us. At first she thought we were copying from each other, but then she noticed our solutions were not only unrelated to what she was teaching, but to each other.

For example, she pulled out our most recent test, which contained a problem involving proving that the four points provided were the corners of a square. I had done something involving line lengths and reciprocal slopes. My mom had shown that the diagonals were the same length and perpendicular. Whereupon I pointed out that this didn't constitute a proof of squareness - unless the diagonals were perpendicular bisectors, you could have a figure known as a "kite", not a square. The teacher was boggled she hadn't even seen the flaw in the reasoning, but let my mom keep the credit for her answer.

In calculus class, the teacher outlined a problem with two yards of specific sorts of shapes, the idea being to enclose the maximum area with a given amount of fence. After a while, he asked what areas people had gotten. Mine was more, so I said so. He said I had the wrong answer. I maintained that my answer was correct, and I could prove it. Sure enough, he called me up to the board to show everybody. I started by drawing the diagram – with the two yards sharing a section of fence. As soon as I drew that, he knew what I had done. He pointed out that no-one had attempted that approach in all the years he had taught the class. He also pointed out that the problem was much harder to solve that way. Heh heh heh.



November 2013

10 111213141516


RSS Atom

Most Popular Tags

Style Credit

Expand Cut Tags

No cut tags
Page generated Jun. 27th, 2017 07:01 am
Powered by Dreamwidth Studios