How to build a particle detector
(also part 1 in an occasional series)
Why am I writing this? Well, I've learned quite a bit on the subject in the last couple of years, and I wanted to share that knowledge in a simple, easy-to-read form. If this fails to interest you, feel free to ignore it.
Anyway, let's consider the purpose of a particle detector. You have one beam of particles coming in from one side, another beam (usually of antiparticles) coming in from the other side, and they collide, hopefully producing new and interesting particles. Your job is to detect as many of these new particles as possible, measuring their properties as completely as you can.
The first consideration is the overall shape. Obviously, when an interesting collision occurs, the new particles will fly off (more or less) randomly in all directions. So, your first thought would be that you want your detector to be a sphere, centered around the point of interaction. This would be true, if collisions only occurred in one solitary point. However, for a variety of reasons, collisions typically occur in an "interaction region" along the beamline a couple of meters long. (To briefly summarize, this increases the number of collisions and thus the odds of actually getting something interesting.) So, your typical particle detector is actually mostly cylindrical centered around this interaction region (usually with caps on the end to catch any stray particles).
The four detectors I know the most about (CDF and D0, the two detectors at Fermilab, the world's current highest-energy collider, and ATLAS and CMS, the two detectors at LHC, which will be the world's highest-energy collider when it opens) all follow the same basic pattern (more or less). If you want to see some layouts, you can see them here:
CDF (or a much nicer PostScript version), D0 (only PostScript, sorry), ATLAS, CMS.
In any case, the general layout in all cases is as follows:
* Closest to the beamline is a silicon detector. The silicon detector is designed for very-high-resolution tracking. This is extremely important to the physics, since some of the particles produced in the initial interaction have very short lifetimes and will thus travel a short distance before decaying again. Identifying the location of the secondary decays ("secondary vertices" in the parlance) allows us to see the presence of these short-lived particles.
The technology used in these silicon detectors is not too different from the technology used in ordinary digital cameras. The detector is made of several layers, each containing a large number of appropriately-prepared silicon strips or pixels. When a particle hits a strip, it knocks off some electrons. By applying a voltage to the strip, these electrons will move to one end, where they can be collected and measured. The big difference between this and your digital camera, of course, is that these detectors operate in an extremely demanding environment. In order to operate at the necessary speeds, very high voltages are are used (typically a few thousand volts), which in turn generates a lot of heat (the silicon can literally melt within minutes if the cooling system fails). Furthermore, the high dose of radiation received this close to the interactions puts a high strain on the electronics used. All in all, it's not an easy job.
The silicon detector is typically not very large. The original CDF silicon detector used is maybe the size of two coffee cans on top of each other; the current one is approximately a foot in diameter and three feet in length (about the size of a large trash can), with some additional layers further out. This is partially because most of these secondary vertices are very close to the interaction point, and partially because the silicon is very expensive.
In general, the amount of silicon is usually limited by cost considerations; over the past 10 years, technology improvement has allowed most detectors to considerably expand their silicon coverage. CMS, in fact, uses silicon for all of their tracking (so they don't have a general-purpose tracker as described below).
* Outside of the silicon tracker is a larger, general-purpose tracker. This is typically a few meters in diameter and a few meters in length. The details vary from detector to detector, but the basic principle is almost always a "drift chamber": you have a large cylinder filled with gas (usually argon or some mix), and some wires running along the length of a cylinder. You apply a positive voltage to some of the wires and a negative voltage to some of the other wires. Again, particles passing through the gas will create some ions, which will drift toward the wires (hence the name) where they can be measured. In CDF, many wires are present in a "cell", while in ATLAS, each wire is isolated in its own "straw".
Drift chambers are a sturdy, (relatively) simple, and (relatively) cheap technology, and they provide good resolution, though obviously not as good as the silicon detectors.
The tracking chambers are typically enclosed in a powerful magnetic field. This magnetic field bends the path of charged particles, so that their momenta can be measured by how much the track is curved (higher-momentum particles will curve less).
* Calorimetry: In contrast to the trackers, where a goal is to disturb the particles as little as possible so that their track can be measured as accurately as possible, the calorimeters have the exact opposite goal: to absorb all of the energy of the particle so that the energy can be accurately measured. Unlike the tracker, where silicon has emerged as the dominant choice, there are a wide variety of technologies used in calorimetry.
The most straightforward way, conceptually speaking, is to use a material which has strong stopping power and emits light as the particles deposit their energy in the material. Then the amount of energy that the particle originally had can be measured by the amount of light emitted. Unfortunately, such materials don't grow on trees; CMS uses crystals of lead tungstate, but these are expensive to fabricate and maintain.
A compromise solution (used in CDF, D0, and ATLAS) is to alternate slabs of a material with strong stopping power (typically lead or steel) with slabs of a material which emits light (either a plastic scintillator or liquid argon). This is much cheaper than the first alternative, since all of the materials are easily available, but at the cost of some resolution. This is called a "sampling" calorimeter.
Calorimetry is, while an extremely valuable technique, inherently limited in its precision: as a particle interacts with the material of the calorimeter, it produces a large "shower" of secondary particles created by the interaction, and measuring the energy from all particles in a shower is inherently imperfect.
Typically, calorimeters are divided into two parts: the inner, or "electromagnetic", section absorbs particles which deposit their energy rapidly (electrons, photons, and pi-zeros), while the outer, or "hadronic" section absorbes heavier particles (hadrons) which lose energy less quickly.
* Muon chambers: Ideally, in the calorimeters everything is absorbed, with two exceptions: neutrinos, which can't (practically speaking) be detected by anything in an ordinary particle detector, and muons. A muon, which is a heavier relative of an electron, is extremely penetrating, and will make it through the lead or steel of the calorimeter without being terribly affected. So, typically, outside the calorimeter there's another tracker which detects the muons (and, occasionally, incoming cosmic rays). This tracker is usually another set of drift chambers, like the central tracker, but with much less demanding specifications (the central tracker has to deal with hundreds of particles in a very small area, while the muon chambers typically only have one or two muons to detect in a much larger area). Muons are very useful as triggers, since the presence of a muon almost always signals that something interesting has happened, so the muon chambers (which tend to be pretty slow) are usually supplemented with fast scintillators (which don't give you much position information, but which do tell you that a muon has passed by) to provide a trigger.
There are, of course, lots of other, smaller, systems involved in a detector, but these are the principal ones.
Friday, February 11, 2005
Friday, January 21, 2005
Musical Interlude #1
(Part of an occasional series, I hope.)
It might not surprise you to learn that the first semester of my senior year in high school (OMG THAT WAS TEN YEARS AGO [hush, you, it's barely more than nine]) was not one of the happiest periods of my life. Sure, my junior year was great, but by senior year, there was the stress of college applications, I had assumed a little more responsibility in various organizations than I was perhaps ready for, and I desperately, desperately needed a girlfriend -- for the sake of brevity, let's just say that things had not been going so well on that front by the time a dark December night rolled around. On that particular night, I had to do a paper for my AP American Government class (on Texas v. Johnson, if my memory serves me correctly). I had put it off to the last moment, as usual, and about 9, I set off for the USF library. (Since my father, at that time, was still teaching for USF, I would occasionally borrow his ID so I could use the library there. The principal advantage was the extended hours, which I was taking advantage of in this case.) Anyway, to sum everything up, I wasn't in the best of moods when I set off, and by the time I arrived, the darkness and the loneliness and the stress had combined to make me miserable. Then, just as I was pulling into a parking spot, a song came over the radio. I sat there in the car and listened to the whole thing, and it was so beautiful, it had a nearly magical effect on me. By the time I got out of the car, I still had work to do, but it felt manageable and I wasn't so unhappy about everything. It's the first time I can recall that a piece of music had anywhere near that profound an effect on me.
Needless to say, while I've tried to replicate this effect later, it's never been quite the same. It was just once of those unique confluences, the right event at the right time, and I'm sure that trying to make it happen probably makes it less likely to work, too. It's still a pretty little piece, though. That piece was the Bergamasca from Ottorino Respighi's Ancient Airs and Dances Suite No. 2. (This was back in the days when I still listened to classical music on the radio some of the time. But that's for another story.)
(Part of an occasional series, I hope.)
It might not surprise you to learn that the first semester of my senior year in high school (OMG THAT WAS TEN YEARS AGO [hush, you, it's barely more than nine]) was not one of the happiest periods of my life. Sure, my junior year was great, but by senior year, there was the stress of college applications, I had assumed a little more responsibility in various organizations than I was perhaps ready for, and I desperately, desperately needed a girlfriend -- for the sake of brevity, let's just say that things had not been going so well on that front by the time a dark December night rolled around. On that particular night, I had to do a paper for my AP American Government class (on Texas v. Johnson, if my memory serves me correctly). I had put it off to the last moment, as usual, and about 9, I set off for the USF library. (Since my father, at that time, was still teaching for USF, I would occasionally borrow his ID so I could use the library there. The principal advantage was the extended hours, which I was taking advantage of in this case.) Anyway, to sum everything up, I wasn't in the best of moods when I set off, and by the time I arrived, the darkness and the loneliness and the stress had combined to make me miserable. Then, just as I was pulling into a parking spot, a song came over the radio. I sat there in the car and listened to the whole thing, and it was so beautiful, it had a nearly magical effect on me. By the time I got out of the car, I still had work to do, but it felt manageable and I wasn't so unhappy about everything. It's the first time I can recall that a piece of music had anywhere near that profound an effect on me.
Needless to say, while I've tried to replicate this effect later, it's never been quite the same. It was just once of those unique confluences, the right event at the right time, and I'm sure that trying to make it happen probably makes it less likely to work, too. It's still a pretty little piece, though. That piece was the Bergamasca from Ottorino Respighi's Ancient Airs and Dances Suite No. 2. (This was back in the days when I still listened to classical music on the radio some of the time. But that's for another story.)
Comments are now fixed
Looks like the change from PHP3 to PHP4 broke the comments. I shold probably junk this old commenting system and get something more modern. Hopefully comment spam won't become a problem. If it does, that might force my hand.
Incidentally, if you did try to comment, it was never recorded, so it's lost into the void. Not that I suspect this is a big problem.
Looks like the change from PHP3 to PHP4 broke the comments. I shold probably junk this old commenting system and get something more modern. Hopefully comment spam won't become a problem. If it does, that might force my hand.
Incidentally, if you did try to comment, it was never recorded, so it's lost into the void. Not that I suspect this is a big problem.
Thursday, January 20, 2005
Celebrating one year of inactivity...oh, damn.
Well, it's now been one year since the last post here. I see that the Blogger interface has changed considerably.
Anyhow, if you're wondering if I'm planning to resurrect the blog, probably not. But there are still occasionally things that I want to post. For instance, the other day we were eating at Fuddrucker's in Emeryville after watching House of Flying Daggers. The sound system was playing the usual extra-schmaltzy Christmas-season music, when suddenly, I noticed an extraordinarily familiar melody: the Troika from the Lt. Kije Suite. You can color me pleasantly surprised.
There's a couple of longer posts which will appear here in the next couple of days.
Well, it's now been one year since the last post here. I see that the Blogger interface has changed considerably.
Anyhow, if you're wondering if I'm planning to resurrect the blog, probably not. But there are still occasionally things that I want to post. For instance, the other day we were eating at Fuddrucker's in Emeryville after watching House of Flying Daggers. The sound system was playing the usual extra-schmaltzy Christmas-season music, when suddenly, I noticed an extraordinarily familiar melody: the Troika from the Lt. Kije Suite. You can color me pleasantly surprised.
There's a couple of longer posts which will appear here in the next couple of days.
Tuesday, January 20, 2004
Iowa madness
Well, I'm procrastinating, so what better way to do it?
Anyway, I was as surprised as anyone by the Iowa caucus results, having pretty much resigned myself to a Dean march to the nomination, whether I liked it or not.
I'm still deeply ambivalent about Kerry. Whenever I actually read something about him (which hasn't been all that often lately, for obvious reasons), I always end up feeling good about him, and from a tactical standpoint he has the requisite gravitas on security issues to compete with Bush (though he arguably overdoes it), but I can't help but worry that the REpublicans will be able to succesfully brand him as another New England patrician. I feel like invoking the name of Dukakis is a little unfair to him, but how can I help it?
Well, it certainly seems like all of the arrows that Dean took as the frontrunner ended up taking their toll on him; the question is whether Kerry will end up suffering the same fate, or whether he can avoid accumulating the amount of dislike that seems to have sunk Dean.
Well, I'm procrastinating, so what better way to do it?
Anyway, I was as surprised as anyone by the Iowa caucus results, having pretty much resigned myself to a Dean march to the nomination, whether I liked it or not.
I'm still deeply ambivalent about Kerry. Whenever I actually read something about him (which hasn't been all that often lately, for obvious reasons), I always end up feeling good about him, and from a tactical standpoint he has the requisite gravitas on security issues to compete with Bush (though he arguably overdoes it), but I can't help but worry that the REpublicans will be able to succesfully brand him as another New England patrician. I feel like invoking the name of Dukakis is a little unfair to him, but how can I help it?
Well, it certainly seems like all of the arrows that Dean took as the frontrunner ended up taking their toll on him; the question is whether Kerry will end up suffering the same fate, or whether he can avoid accumulating the amount of dislike that seems to have sunk Dean.
Thursday, January 08, 2004
I hate, hate, hate the New York sports media
Why, you ask? Because they have to subject the rest of us to their preposterous rumors. If I don't want to read about how the Warriors should trade Mike Dunleavy and Calbert Cheaney for Tracy McGrady, all I have to do is avoid the loonier message boards. But trying to escape from rumors that the Knicks are on the verge of trading Kurt Thomas and Charlie Ward for Nick Van Exel is impossible. Never mind the fact that anyone not located within the boundaries of greater New York realizes that Kurt Thomas and Charlie Ward are worth about a large Slurpee. Never mind the fact that the Warriors repeatedly denied that they had any interest at all in the deal (thus proving that, for all their other failings, they're at least not total idiots). No, as long it's something the New York fans would like to see happen, it's something we have to read about. (Note that the Knicks finally did succeed in moving Charlie Ward. The Suns showed their appreciation of his fantastic value by promptly cutting him.)
Now, I read some drivel that the Mets are interested in signing Vladimir Guerrero. Note that the story does not say anything about Guerrero being interested in signing with the Mets. Nor should it, given that the Mets' offer is substantially lower than the Expos offer he's already rejected, and also substantially lower than the offer he's discussing with the Orioles. And yet, it's news. Why? Because it's something New York would like to see happen, of course. (Why wouldn't they?) Even worse than this initial report is this Bob Klapisch bleating about why Vlad should come to New York, despite the lack of money. (Never mind the fact that all previous reports have indicated that New York is not a place where he would want to play; if the Mets want to sign him, well then of course he would want to play there!) The Mets have had a pretty decent offseason, but for Klapisch to glowingly describe Braden Looper as "the best available closer" is just the kind of thing that drives me batty.
Why, you ask? Because they have to subject the rest of us to their preposterous rumors. If I don't want to read about how the Warriors should trade Mike Dunleavy and Calbert Cheaney for Tracy McGrady, all I have to do is avoid the loonier message boards. But trying to escape from rumors that the Knicks are on the verge of trading Kurt Thomas and Charlie Ward for Nick Van Exel is impossible. Never mind the fact that anyone not located within the boundaries of greater New York realizes that Kurt Thomas and Charlie Ward are worth about a large Slurpee. Never mind the fact that the Warriors repeatedly denied that they had any interest at all in the deal (thus proving that, for all their other failings, they're at least not total idiots). No, as long it's something the New York fans would like to see happen, it's something we have to read about. (Note that the Knicks finally did succeed in moving Charlie Ward. The Suns showed their appreciation of his fantastic value by promptly cutting him.)
Now, I read some drivel that the Mets are interested in signing Vladimir Guerrero. Note that the story does not say anything about Guerrero being interested in signing with the Mets. Nor should it, given that the Mets' offer is substantially lower than the Expos offer he's already rejected, and also substantially lower than the offer he's discussing with the Orioles. And yet, it's news. Why? Because it's something New York would like to see happen, of course. (Why wouldn't they?) Even worse than this initial report is this Bob Klapisch bleating about why Vlad should come to New York, despite the lack of money. (Never mind the fact that all previous reports have indicated that New York is not a place where he would want to play; if the Mets want to sign him, well then of course he would want to play there!) The Mets have had a pretty decent offseason, but for Klapisch to glowingly describe Braden Looper as "the best available closer" is just the kind of thing that drives me batty.
Monday, January 05, 2004
The whole story on the A-Rod issue
I just saw this article, and I think it has the most complete account of the A-Rod deal that I've seen. Interesting reading.
I just saw this article, and I think it has the most complete account of the A-Rod deal that I've seen. Interesting reading.
Tuesday, December 30, 2003
Interesting legal issue of the day
I won't try to summarize this, so I'll just give you this link.
Caution: Contains descriptions of pornographic acts.
I won't try to summarize this, so I'll just give you this link.
Caution: Contains descriptions of pornographic acts.
And now, the other side of the below entry
Apparently, some conservative sites, like Free Republic, do this kind of thing too!
*pause for surprised reactions*
Yeah, that's what I thought. Anyway, I'm certainly not going to attack their right to do so, either.
Apparently, some conservative sites, like Free Republic, do this kind of thing too!
*pause for surprised reactions*
Yeah, that's what I thought. Anyway, I'm certainly not going to attack their right to do so, either.
Friday, December 19, 2003
My two cents on comment "censorship"
So I was going to post this as a comment on Matt's blog, but I figured I had enough to say that it deserved my own entry. Plus, I haven't posted anything here in a while, so this gives me the chance to kill two birds with one stone.
Anyway, apparently the official blog of the DNC, Kicking Ass, will delete comments with opposing viewpoints. This has got some people all hot and bothered. As you might have guessed from the scare quotes in the title, I'm somewhat less concerned about it. My dismissal rests on two points, one practical and one theoretical:
1) Practially speaking, what exactly do these Republican commentators hope to accomplish by posting argumentation on Kicking Ass? If their goal is to convince the blog writers that they're wrong, then they're idiots. This is not going to happen. Perhaps they would claim that they are trying to convince undecided centrists. If so, they should convince me first that there are really any undecided centrists reading Kicking Ass; if I were an undecided centrist, I certainly would not expect the official blog of the DNC to be a source meeting my political needs. Really, the only thing that they're doing is engaging in argumentation for argumentation's sake, and I have no hesitation in calling that completely unproductive.
2) On a more theoretical note, why would they expect any different? Comments are under no obligation to always be a forum for free exchange of ideas. The main purpose of Kicking Ass, at least as I would see it, is not to be a place for equal discussion among all political viewpoints; it's a place to mobilize people who already have one particular viewpoint. Why should they be under any obligation to entertain others, then?
So I was going to post this as a comment on Matt's blog, but I figured I had enough to say that it deserved my own entry. Plus, I haven't posted anything here in a while, so this gives me the chance to kill two birds with one stone.
Anyway, apparently the official blog of the DNC, Kicking Ass, will delete comments with opposing viewpoints. This has got some people all hot and bothered. As you might have guessed from the scare quotes in the title, I'm somewhat less concerned about it. My dismissal rests on two points, one practical and one theoretical:
1) Practially speaking, what exactly do these Republican commentators hope to accomplish by posting argumentation on Kicking Ass? If their goal is to convince the blog writers that they're wrong, then they're idiots. This is not going to happen. Perhaps they would claim that they are trying to convince undecided centrists. If so, they should convince me first that there are really any undecided centrists reading Kicking Ass; if I were an undecided centrist, I certainly would not expect the official blog of the DNC to be a source meeting my political needs. Really, the only thing that they're doing is engaging in argumentation for argumentation's sake, and I have no hesitation in calling that completely unproductive.
2) On a more theoretical note, why would they expect any different? Comments are under no obligation to always be a forum for free exchange of ideas. The main purpose of Kicking Ass, at least as I would see it, is not to be a place for equal discussion among all political viewpoints; it's a place to mobilize people who already have one particular viewpoint. Why should they be under any obligation to entertain others, then?
Tuesday, December 02, 2003
Restaurant recommendation
So we used to eat at the Hot Pot City on University every so often (it was even a tradition, for a while, to eat there after a Simbase draft), so I was a little disappointed when it went under. Then a new Japanese restaurant, Tanaka, sprang up there, and I decided that I wanted to try it to see if it was a worthy successor to HPC. When we took everyone out to dinner who had helped us to move (and thank you, everyone!), I thought this would be as good a time as any to try it.
Anyway, to say that the atmosphere inside was a little different from the old Hot Pot City would be a minor understatement -- Juliana even wondered if we were dressed well enough -- but we were all very pleasantly surprised by the quality and quantity of the food (the latter often being difficult to get at a Japanese restaurant without paying a lot of money!) And despite all of that, the prices were less than I would have expected.
Plus, it's very near our new place. This is good.
So we used to eat at the Hot Pot City on University every so often (it was even a tradition, for a while, to eat there after a Simbase draft), so I was a little disappointed when it went under. Then a new Japanese restaurant, Tanaka, sprang up there, and I decided that I wanted to try it to see if it was a worthy successor to HPC. When we took everyone out to dinner who had helped us to move (and thank you, everyone!), I thought this would be as good a time as any to try it.
Anyway, to say that the atmosphere inside was a little different from the old Hot Pot City would be a minor understatement -- Juliana even wondered if we were dressed well enough -- but we were all very pleasantly surprised by the quality and quantity of the food (the latter often being difficult to get at a Japanese restaurant without paying a lot of money!) And despite all of that, the prices were less than I would have expected.
Plus, it's very near our new place. This is good.
An accumulation of random things from the past couple of weeks
1) Where does the thing where a person looks at his face in a mirror after surgery, laughs maniacally, and then smashes the mirror come from? I've seen it parodied a million times, but I have no idea what the source is.
2) For some reason, there's been a number of articles on Wal-Mart lately. One of them had a comment at the end (I'm too lazy to look it up at the moment) which said something like, "We all want someone else to buy the more expensive goods." And this is really what it all comes down to, isn't it? It's one big Prisoner's Dilemma. If everyone were willing to pay a little bit more for goods, then the economy would probably be in better shape overall, since stores would be able to afford things like keeping production in America, but each individual customer feels that they're better off buying at Wal-Mart (true), and so we end up in the Nash equilibrium.
3) I know I've commented on this before, but I find this really puzzling. The suffix -let is normally a diminutive (eaglet, wavelet, etc.) But when used to apply to professions, it usually means not only young, but also female. I can call Britney Spears a pop starlet, but I certainly can't call Justin Timberlake a starlet. I can call Kate Bosworth a movie starlet, but not Hayden Christensen. Yet an eaglet doesn't have to be female...
4) You know that your monitor emits radio-frequency emissions, right? (This is actually, theoretically at least, a potential security concern -- it's not inconceivable that someone could read what's on your monitor with a sufficiently sensitive radio receiver.) Well, this program can use those emissions to transmit music by putting the appropriate patterns on your monitor.
1) Where does the thing where a person looks at his face in a mirror after surgery, laughs maniacally, and then smashes the mirror come from? I've seen it parodied a million times, but I have no idea what the source is.
2) For some reason, there's been a number of articles on Wal-Mart lately. One of them had a comment at the end (I'm too lazy to look it up at the moment) which said something like, "We all want someone else to buy the more expensive goods." And this is really what it all comes down to, isn't it? It's one big Prisoner's Dilemma. If everyone were willing to pay a little bit more for goods, then the economy would probably be in better shape overall, since stores would be able to afford things like keeping production in America, but each individual customer feels that they're better off buying at Wal-Mart (true), and so we end up in the Nash equilibrium.
3) I know I've commented on this before, but I find this really puzzling. The suffix -let is normally a diminutive (eaglet, wavelet, etc.) But when used to apply to professions, it usually means not only young, but also female. I can call Britney Spears a pop starlet, but I certainly can't call Justin Timberlake a starlet. I can call Kate Bosworth a movie starlet, but not Hayden Christensen. Yet an eaglet doesn't have to be female...
4) You know that your monitor emits radio-frequency emissions, right? (This is actually, theoretically at least, a potential security concern -- it's not inconceivable that someone could read what's on your monitor with a sufficiently sensitive radio receiver.) Well, this program can use those emissions to transmit music by putting the appropriate patterns on your monitor.
Public service announcement
All right, if you're wondering why the lack of updates lately, it's at least partially because I've been busy moving. And it'll still probably be another week before I get broadband (whine!) so I'll probably be intermittent at best.
Thank you for your patience,
The Management
All right, if you're wondering why the lack of updates lately, it's at least partially because I've been busy moving. And it'll still probably be another week before I get broadband (whine!) so I'll probably be intermittent at best.
Thank you for your patience,
The Management
Thursday, November 13, 2003
The things I have to deal with at work
Mostly I'm just writing this out for my own benefit, so I can see its awfulness with my own eyes.
In order to run the main hybrid test program I use here at work, I
1) run a Perl script, which nicely generates the arguments and passes them to...
2) a shell script, whose main purpose is to call...
3) another shell script (written in tcsh), which checks that everything is in order and then calls...
4) a C program with an embedded Tcl interpreter, whose first action is to call...
5) a Tcl script, which again checks that everything is in order and then calls....
6) a C routine within (4) to run the main testing program.
Just to confuse things more, (2) and (5) are actually the same file, with some cleverly-written half-commented shell at the beginning so that it'll go to (3) when called as a shell script and (6) when invoked as a Tcl script.
Needless to say, if I had my druthers, I'd rip out 90% of this labyrinth. Sadly, I don't...at least for now.
Mostly I'm just writing this out for my own benefit, so I can see its awfulness with my own eyes.
In order to run the main hybrid test program I use here at work, I
1) run a Perl script, which nicely generates the arguments and passes them to...
2) a shell script, whose main purpose is to call...
3) another shell script (written in tcsh), which checks that everything is in order and then calls...
4) a C program with an embedded Tcl interpreter, whose first action is to call...
5) a Tcl script, which again checks that everything is in order and then calls....
6) a C routine within (4) to run the main testing program.
Just to confuse things more, (2) and (5) are actually the same file, with some cleverly-written half-commented shell at the beginning so that it'll go to (3) when called as a shell script and (6) when invoked as a Tcl script.
Needless to say, if I had my druthers, I'd rip out 90% of this labyrinth. Sadly, I don't...at least for now.
Monday, November 10, 2003
Literary game #2
This question seems surprisingly hard: What book titles can you think of which are also complete sentences?
So far I can come up with two: Atlas Shrugged and No One Writes to the Colonel. You'd think that with all of the literature out there, I'd be able to come up with more, but it's just that they're all noun phrases (or, in a few cases, prepositional phrases, like Around the World in 80 Days).
This question seems surprisingly hard: What book titles can you think of which are also complete sentences?
So far I can come up with two: Atlas Shrugged and No One Writes to the Colonel. You'd think that with all of the literature out there, I'd be able to come up with more, but it's just that they're all noun phrases (or, in a few cases, prepositional phrases, like Around the World in 80 Days).
Literary game #1
Here's a question I've been turning over in my mind for a little while: What words sound like they should mean the opposite of what they actually do mean?
"Temerity" is the big one here. It always seems to me that it should mean "timidity", rather than the opposite. The other one is "truculent", which I feel should mean something more like "obsequious".
Here's a question I've been turning over in my mind for a little while: What words sound like they should mean the opposite of what they actually do mean?
"Temerity" is the big one here. It always seems to me that it should mean "timidity", rather than the opposite. The other one is "truculent", which I feel should mean something more like "obsequious".
Blah
So I had another quizbowl tournament this weekend, the combined TRASH regionals/Technophobia at Caltech. Overall it was a good experience, and I certainly can't complain about our performance, but it was a lot of quizbowl -- we ended up playing well past 1 on Friday night, and then twelve more rounds on Saturday.
I think every time I have to drive back from LA, I enjoy it a little less. And given that I didn't exactly love the drive the first time around, I wouldn't complain too loudly if we never went to any more tournaments down in the southern part of the state. Of course, this time was bad just because I was so tired and it was rainy, which made driving just that little bit more difficult. In better circumstances, I probably wouldn't have minded too much.
So I had another quizbowl tournament this weekend, the combined TRASH regionals/Technophobia at Caltech. Overall it was a good experience, and I certainly can't complain about our performance, but it was a lot of quizbowl -- we ended up playing well past 1 on Friday night, and then twelve more rounds on Saturday.
I think every time I have to drive back from LA, I enjoy it a little less. And given that I didn't exactly love the drive the first time around, I wouldn't complain too loudly if we never went to any more tournaments down in the southern part of the state. Of course, this time was bad just because I was so tired and it was rainy, which made driving just that little bit more difficult. In better circumstances, I probably wouldn't have minded too much.
Thursday, November 06, 2003
My 2 cents on the Confederate flag uproar
Not much to say that hasn't been said elsewhere, but to me, this tells me two things:
1) The other Democrats are desperate to blunt Dean's momentum. The way that they've seized onto this issue, it looks like they're desperate for an angle with which they can gain an edge (to ruthlessly mix metaphors).
2) Fundamentally, Dean is right, even if he didn't exactly express himself in the best way possible. However, I can't see the Democratic party reversing its losses in the South in the near future without a major sea change.
Not much to say that hasn't been said elsewhere, but to me, this tells me two things:
1) The other Democrats are desperate to blunt Dean's momentum. The way that they've seized onto this issue, it looks like they're desperate for an angle with which they can gain an edge (to ruthlessly mix metaphors).
2) Fundamentally, Dean is right, even if he didn't exactly express himself in the best way possible. However, I can't see the Democratic party reversing its losses in the South in the near future without a major sea change.
Two political links of the day
First, the most distinctive ballot measure you're likely to see (not counting San Francisco's Proposition BB of about ten years back, which is a close contender): this measure in Bolinas.
Second, apparently the Democratic party switched from winner-take-all primaries to proportional representation. Yes, really. This should make for an interesting convention. Read about it in CalPundit.
First, the most distinctive ballot measure you're likely to see (not counting San Francisco's Proposition BB of about ten years back, which is a close contender): this measure in Bolinas.
Second, apparently the Democratic party switched from winner-take-all primaries to proportional representation. Yes, really. This should make for an interesting convention. Read about it in CalPundit.
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