CompUSA has some crazy deals on monitors. 24″ Acer LCD (1920×1200) for $250 after rebate, and a 22″ Acer (1600×1050) for $170 after rebate.
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Category Archives: Cool Links
Filesystems
On my continuing obsession with squeezing every bit of performance out of this system… They say that Linux filesystems don’t get fragmented. I never understood this. It’s apparently smarter about where files are placed. But still, frag-proof? If it was that easy, other filesystems would have figured it out long ago too. I figured that the explanation was just over my head. In reality, the “explanation” is that it’s a myth.
oxygen bin # fragck.pl /home 2.19458018658374% non contiguous files, 1.03385162150155 average fragments. oxygen bin # fragck.pl /var/log 56.3218390804598% non contiguous files, 28.9425287356322 average fragments. oxygen bin # fragck.pl /var/www/ 1.45061443222766% non contiguous files, 1.05527580153377 average fragments. oxygen bin # fragck.pl /etc 2.18023255813953% non contiguous files, 1.05450581395349 average fragments. oxygen bin # fragck.pl /var/lib/mysql/ 16.5424739195231% non contiguous files, 2.93740685543964 average fragments.
The results kind of make sense: /var/log is full of files where you’re constantly appending a line or two to various files, so it only stands to reason that, if the filesystem isn’t very careful, fragmentation would build up. The other one is /var/lib/mysql, where MySQL stores its data. It’s the same deal as /var/log, really, in that it’s continually adding files.
/var/log/messages, the system log file, is in 75 pieces. Its backup, messages.1.gz,was in 68.
Realistically the performance hit is negligible. It’s not like a core system file is in hundreds of pieces. (Like, say, the paging file!) /bin has very low fragmentation. Log files can be fragmented an not impact anything. (Except my OCD.) Although I am concerned about MySQL’s data stores building up fragmentation. In theory I can bring the database down and shuffle the files around, but it’s probably best left alone right now.
Fortunately, there’s hope… By moving a file to another partition, you cause it to move physical locations. Something like mv messages /tmp/ramdisk && mv /tmp/ramdisk/messages . will cause the file to be rewritten. (Granted, this particular command was an awful idea: syslog-ng keeps /var/log/messages open, and doesn’t like it when the file randomly disappears. The fact that it was only gone for a split-second doesn’t change the fact that the files location has changed.) Although don’t get too excited about this: for some reason, fragmentation sometimes ends up worse! access_log was in 60 pieces. Now it’s in 76.
I’ve also heard it said that some fragmentation isn’t necessarily a bad thing: a few files close together on the disk with light fragmentation is better than frag-free files on opposite ends of the disk. But that doesn’t satisfy my OCD. I guess the moral of the story is to not muck around too much with things. Or, “if it ain’t broke, don’t fix it!”
M/S Explorer Crashes Again
M/S Explorer has crashed.
For added irony, they were in penguin territory at the time.
(One wonders the view out the Windows now that the ship is on its side–they’re most likely blue screens! No Word on whether that is the case, of course, but I will say that the ship’s Outlook isn’t so good. Fortunately, because the rescuers Excel at what they do, passengers were able to Exchange their rooms for ones on a stable ship. Because there were no fatalities, this was not FrontPage news, except on Digg.)
ISO: The Next Frontier?
In photography, there are a few key variables in determining exposure. The first is the aperture of the lens: basically, how much light is let in. Really serious (or rich) photographers carry around very “fast” lenses–they’re enormous and let in a ton of light. Notice the huge lenses that you see on the sidelines as sporting events, for example. (Err, not the length, but the width–these things are huge in both dimensions.) Of course, these lenses (we call them “fast” lenses, or lenses with wide apertures) are very heavy, and insanely expensive: for a really good one, you’d pay at least $1,000, and that’s pocket change compared to some lenses.
Another control is ISO sensitivity. Back in the days of film, some film was more sensitive to light than others. For example, ISO100 produces great pictures, but requires a lot of light. It’s superb for outdoor pictures on a sunny day. On the other hand, if you’re getting shots indoors, you might be at something like ISO1600. The problem is that, as you increase the sensitivity, you also increase the noise. ISO1600 will get decent shots indoors, but they’ll be grainy. (This is especially bad if you’re like me and tend to try to boost details in the shadows in Photoshop.)
The two come together to control the third important variable, shutter speed. In some cases, it doesn’t matter a ton. If it’s bright and sunny, and I’m taking a picture of a building, I really couldn’t care whether it’s 1/100th of a second or 1/4,000th of a second. And, if I’m using a tripod, it’s not uncommon to have shutter speeds lasting several seconds. But the problem is that, if the shutter speed is too low, you get a lot of blur. There are two reasons–the first is that people rarely hold still. I use 1/60 as a general rule of thumb: below that and you risk some blur if people are moving a lot. This is a really rough guess: I’ve gotten great portraits at 1/8, and sometimes 1/125 isn’t fast enough.
The bigger consideration, though, is camera shake, especially with longer zoom lenses. The rule of thumb there is 1/length. For example, shooting with a telephoto 200mm lens, it’s recommended that I shoot a 1/200 of a second or faster.
Putting it all into practice… Bill Clinton was speaking tonight at an event we went to. I have a 55-200mm telephoto lens, and tended to stay right around 200mm. I stayed at ISO1600; I can go to ISO3200 but it’s very grainy so I don’t use it. Unfortunately, though, my lens can’t go wider than f/5.6 at that length, which meant that the fastest I could get shots was around 1/60th of a second. At 200mm, this really was inadequate: most of the shots came out okay because I have a steady hand, but they’re not all that sharp. Example:
It’s okay, but now compare it to this picture:
Granted, the subject isn’t that interesting, but every time I see that shot I took, I think, “Wow, that’s sharp!” Not so for the Clinton photo. If you view it in larger detail (click on it), its subtle blur becomes increasingly obvious.
There was a professional photographer about ten feet away from me. She was shooting a 70-200mm lens, which is a similar length to mine. But hers is an f/2.8 lens, which lets in twice as much light as mine does. So while I was getting 1/60 shutter speeds, she could have been getting 1/120. (Hers had Image Stabilization, too, but that’s a story for another day.)
The thing is, taking telephoto portraits indoors isn’t all that rare of a thing to do. To get good shots, you need to get that shutter speed up. There are two ways to do it, as you should now know: raise ISO or get a better lens. The problem is that getting a better lens will set me back $5,000 or so. And it’s an insanely heavy lens as well.
The other option is one that, until recently, wasn’t feasible: raise ISO some more. ISO1600 is good. You can do ISO3200, but it’s decent on only a few cameras. But I really have to give Nikon credit with their D3. It’ll go to ISO25600. Check out some samples. I’ve seen some higher-res images at ISO6400, and it’s just about perfect! Its ISO6400 rivals my ISO1600. The thing is, that’s a huge increase to be able to shoot at 6400 and have a perfectly usable image. It would have helped a lot with getting better shots.
I truly hope this is the direction camera makers go in now, and that Canon and Nikon get into an “ISO war” trying to outdo each other.
vim Trick of the Day
:g/nbsp/d
That command sets up a “range” of all lines (hence the g for global) that match “nbsp”, and runs the command “d” (delete) on them.
I’m working with a file that was converted by a script from HTML, but had some carryovers that were whole unnecessary lines… No lines with ‘desirable’ content had the nbsp in them, just the junk ones. So we delete them all.
Kudos to this site for the inspiration.
There Goes My Hero
Watch him as he goes! It was the usual “wasting time on Wikipedia” path — I started reading about nuclear fission, and then read about Los Alamos, and then read about the supercomputers, one of which ran Plan 9, so I read about Plan 9, and then its GUI, and then the guy who wrote the GUI. And there was an allusion to someone else, Mark V. Shaney. So I read about him.
In a nutshell, it was a script a few of the Plan 9 guys wrote that would process a lengthy body of text and do some statistical analysis, and use that to spit out writing. It was AI, in a sort, but “schizophrenic” is the best way I’ve seen it described. You read it and it’s one of those things where, for a minute, it makes sense, but then it radically shifts topics or draws some sort of completely irrelevant conclusion. Kind of like a lot of people on the Internet, actually.
They had some fun with textbooks. Here‘s an example, in which the code was fed a basic arithmetic textbook:
Why do we count things in groups of five. When people learned how to count many things, they matched them against their fingers. First they counted out enough things to match the fingers of both hands. Then they put these things aside in one quart. A giant-size bottle that will hold four quarts is a three-digit number….
It starts of making good sense, but suddenly they go from counting on your fingers to putting “these things” in a quart, and is pretty incomprehensible from there.
Here’s another really funny one. You read it, and can kind of comprehend it. But the first reply summarizes it well: it suddenly shifts from constipation to understanding the 19th century, with no logical shift. I think that commenter may have been aware of what was going on. The second guy accurately nails what’s going on.
Finnegan’s Wake? This one cracks me up a lot. But you read this, and doesn’t it exactly sum up what’s wrong with Internet forums? The people just seem totally bonkers, and like they’re ranting but not really sure what they’re ranting about. He manages to talk about being good in bed and using the latest version of BSD in the same sentence. The reply is hilarious, because it’s exactly what you’d think if you didn’t know what was going on: that the “guy” posting was on some serious drugs.
This one, though, is my all-time favorite. It starts off as some religious rant, but clearly not a coherent one. But the fifth paragraph is the best paragraph ever written:
When I meet someone on a professional basis, I want them to shave their arms. While at a conference a few weeks back, I spent an interesting evening with a grain of salt. I wouldn’t take them seriously!
I’m fairly certain there are AI ‘bots’ out there that do this same thing, maybe in more coherent forms. I want to acquire one. Badly. I’ve always been interested in the ‘bounds’ of nonsense—when something kind of makes sense, you work with it. We “understand” people shaving their arms in professional settings, and we can visualize someone spending an evening with a grain of salt, and I surely wouldn’t take them seriously afterwards. But we’re making ‘sense’ out of sheer nonsense generated by a computer. How far will it go before we think, “This is complete nonsense.”
Deal of the Day
Lot of 10 machetes, currently 99 cents. Do mind the shipping ($19.99), though.
One may also wish to ask themselves, “Wait, what do I need ten machetes for?” (And, furthermore, “Is it legal to possess machetes on campus?,” which is a decided “Not at all” in my case.) But for those of you living where machetes are allowed, and who can come up with some reason for owning them, this is currently a steal!
Stolen Ideas, II
Hammacher Schlemmer has a second idea that’s eerily similar to something I’ve had in mind.
Granted, mine would be an order of magnitude (or two) more expensive, have a cell modem for enormous range, solar panels to aid it in flying for a long time, and an ultra-high res camera with a long zoom lens… 640×480 is pretty much a gimmick, especially when you can only store 26 of them. And a 7-minute battery life is gimmicky too. I want a high-quality lens and 8 good megapixels. And a 4GB flash drive or something.
Oh, and GPS. And WiFi. I want to be able to, on the computer, map out a path for it to fly over, and automatically ‘return home.) Granted, you’re far, far from the $200 price at that point. But it’s also seriously cool at that price.
Flock Test
This is a test post with Flock. It’s pretty diverse in what it supports for blog APIs. Do the MetaWeblog and set the link to http://blogs.n1zyy.com/YOU/xmlrpc.php
Five-minute review: very impressed.
Blogged with Flock
My Vacuum!
These guys stole my idea! Some iterations of my idea also featured an air ionizer, though. And all iterations of my vacuum idea were to be uncommonly powerful.
Oh well.