Shallow Thoughts : : Sep

Akkana's Musings on Open Source Computing and Technology, Science, and Nature.

Tue, 30 Sep 2008

Life in the Baitball

I'm flying R/C electric planes again. I'd overdone it a few years ago and burned out; it stopped being fun and I had to take a long break from flying.

But lately I'd been hearing intriguing stories from Dave about the group he flies with at Baylands. They weren't doing the endless hovering-and-rolling-circles that's all the rage in electric R/C circles. (Not to disparage 3-D flying; anyone who can coordinate a rolling circle gets my respect as a pilot. I just lost interest in spending much time at that sort of flying myself.

No, what they've been doing lately is combat flying ... dogfighting. The kind of flying I always thought looked most fun, only Dave and I could never get anyone else interested. You mean, there's a whole group of people dogfighting and I'm missing it?

When I came out to visit, a couple of my old dusty planes in tow, Dave let me use one of his old Boomers (a bit easier for a rusty pilot to fly than the full-on Wild Wing) for the combat. We only had 4-5 planes in the air, but I was hooked right away. Dogfighting is way more fun with five planes than it is with only two. It's still surprisingly difficult to hit each other, even when that's what everyone's trying to do. But even when you don't make contact, it's exciting and beautiful.

When you get a lot of planes in the air, twisting and turning and looping and trying to stay in a little compact region because that makes it more likely they'll hit, Dave put his finger on what it's most like. You know those David Attenborough nature shows where a huge school of sardines or anchovies has gathered, and dolphins herd them into a tight compact ball of shining shimmering silvery streaks, and then the seabirds come and dive from the air while the dolphins are darting in and out from below? Attenborough calls it a bait ball, and that's what Dave calls our combats.

We're gradually pulling in fresh mea--er--new recruits to add to the fun. A week ago last Saturday we all trooped up to Dublin to meet with some east bay combat flyers. We had as many as ten planes all fighting at once. Pete has a video online of the Dublin Melee ... video from a digital camera really doesn't get the feeling across, but it's a start, and gives some idea of the challenge of keeping track of which plane is yours.

Try imagining David Attenborough narrating about the bait ball while you watch the video. Helps a little, doesn't it? Or if you're going for the feel of combat, ditch the narration and play something like the "Asteroid Field" theme from the first Star Wars.

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[ 22:20 Sep 30, 2008    More misc | permalink to this entry | comments ]

Sun, 28 Sep 2008

Avoiding jargon may be harder than you think

An interesting occurrence at a Toastmasters meeting last week offered a lesson in the difficulties of writing or speaking about technology.

The member who was running Table Topics had an interesting project planned: "Bookmarks". I thought, things you put in books to mark your place? Then I saw the three-page printout he had brought and realized that, duh, of course, he means browser bookmarks.

The task, he explained, was to scan his eclectic list of bookmarks, pick three, and tell a story about them.

Members reacted with confusion. Several of them said they didn't understand what he meant at all. Would he give an example? So he chose three and gave a short demonstration speech. But the members still looked confused. He said if they wanted to pick just one, that would be okay. Nobody looked relieved.

We did a couple rounds. I gave a rambling tale that incorporated three or four bookmarks. One of our newer members took the list, and wove a spirited story that used at least five (she eventually won the day's Best Table Topic ribbon). Then the bookmark list passed to one of the members who had expressed confusion.

She stared at the list, obviously baffled. "I still don't understand. What do they have to do with bookmarks?" "Browser bookmarks," I clarified, and a couple of other people chimed in on that theme, but it obviously wasn't helping. Several other members crowded around to get a look at the list. Brows furrowed. Voices murmured. Then one of them looked up. "Are these like ... Favorites?"

There was a immediate chorus of "Favorites?" "Oh, like in an Explorer window?" "You mean like on the Internet?" "Ohhh, I think I get it ..." Things improved from there.

I don't think the member who presented this project had any idea that a lot of people wouldn't understand the term "Bookmark", as it applies to a list of commonly-visited sites in a browser. Nor did I. I was momentarily confused thinking me meant the other kind of bookmark (the original kind, for paper books), but realizing that he meant browser bookmarks cleared it right up for me. A bigger surprise to me was that the word "browser" wasn't any help to half the membership -- none of them understood what a "browser" was any more than they knew what a "bookmark" was. "Like in an Explorer window?" or "on the internet" was the closest they got to the concept that they were running a specific program called a web browser.

These aren't stupid people; they just don't use computers much, and haven't ever learned the terminology for some of the programs they use or the actions they take. When you're still learning something, you fumble around, sometimes getting where you need to go be accident; you don't always know how you got there, much less the terms describing the steps you took. Even if you're an übergeek, I'm sure you have programs where you fumble about and aren't quite sure how you get from A to B.

You may sometimes be surprised at meeting people who still use Internet Explorer and haven't tried Firefox, let alone Opera. You may wonder if it's the difficulty of downloading and installing software that stops them. But the truth may be that questions like "Have you tried Firefox?" don't really mean anything to a lot of people; they're not really aware that they're using Internet Explorer in the first place. It's just a window they've managed to open to show stuff on the internet.

Avoiding technical jargon is sometimes harder than you think. Seemingly basic concepts are not so basic as they seem; terms you think are universal turn out not to be. You have to be careful with terminology if you to be understood ... and probably the only way to know for sure if you're using jargon is to try out your language on an assortment of people.

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[ 12:23 Sep 28, 2008    More tech | permalink to this entry | comments ]

Wed, 24 Sep 2008

Akk and the Night Visitor

Last night we spotted a masked bandit at the office door.

[Raccoon at the door] The raccoon was in a nutty mood -- or at least in a mood to eat a lot of hazelnuts and cashews.

Happily, I had the DSLR on my desk and was able to sneak some shots. Last time we were visited by raccoons I established that unlike most wildlife, raccoons definitely do notice a camera's flash, and don't like it a bit. (Most birds, reptiles, amphibians and even rodents are remarkably un-bothered by flash and don't seem to notice it at all.) So the Rebel's ISO1600 and ability to focus in dim light came in very handy. (Have I mentioned how much fun it is having an SLR again?)

The 'coon licked the nut shelf clean, then headed north to the neighbor's house. This bandit worked alone -- no partner this time.

A few more raccoon photos here.

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[ 23:44 Sep 24, 2008    More nature | permalink to this entry | comments ]

Mon, 22 Sep 2008

Linux Planet: Linux Astronomy part III: Stellarium and Celestia

Part III in the Linux Astronomy series on Linux Planet covers two 3-D apps, Stellarium and Celestia.

Writing this one was somewhat tricky because the current Ubuntu, "Hardy", has a bug in its Radeon handling and both these apps lock my machine up pretty quickly, so I went through a lot of reboot cycles getting the screenshots. (I found lots of bug reports and comments on the web, so I know it's not just me.) Fortunately I was able to test both apps and grab a few screenshots on Fedora 8 and Ubuntu "Feisty" without encountering crashes. (Ubuntu sure has been having a lot of trouble with their X support lately! I'm going to start keeping current Fedora and Suse installs around for times like this.)

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[ 22:10 Sep 22, 2008    More writing | permalink to this entry | comments ]

Thu, 18 Sep 2008

The Alum Rock Narrows

On a trip a couple years ago, Dave and I sought out an interesting geologic phenomenon: the Victorville Narrows of the Mojave river, after reading the discussion of it in Geology Underfoot in Death Valley and Owens Valley by Robert P. Sharp.

The Mojave river is interesting because for most of its length it flows entirely underground. Looking at the wide, sandy, dry washes along the many miles of its length you'd never suspect that a year-round river was flowing beneath the surface.

One of the few places it comes to the surface is near Victorville, CA, where a big chunk of rock gets in the way and forces the water to the surface for a short distance before it disappears back into another sandy wash.

That's all background to the interesting discovery we made at Alum Rock park yesterday, where Penitencia creek and its tributary, Aguage creek, have been looking progressively drier over this past month.

[big fish in Penitencia Cr] Walking upstream along the creek trail, we saw a fairly normal looking lower creek up to the bridge at the last parking lot. Just a little further upstream beyond that parking lot, the creek follows a series of little cascades and pools. The pools are only a few feet deep at this time of year ... but in one, we saw quite a large fish, about a foot long and looking vaguely catfishy. How does something that big live in a stream this shallow and ephemeral?

Not only that, but just upstream, as the stream crossed under the park road near Sycamore Grove, it disappeared. We knew there had to be water because something was feeding those pools and the lower creek -- but it was all underground here. We continued upstream, and discovered ... the Alum Rock Narrows! Right by the steel bridge over the creek, the dry Penitencia and Aguage creeks become wet as water is forced to the surface at their confluence, only to disappear again some fifty feet downstream of the bridge.

It was very like the Victorville Narrows in miniature ... right here in the big city. Not for the first time, I wish I could find a decent geologic map of this fascinating park!

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[ 22:26 Sep 18, 2008    More nature/trails | permalink to this entry | comments ]

Sat, 13 Sep 2008

Un-Jamming an Epson C86

I turned on my printer to print out a form I needed to mail and it emitted a nasty high-pitched noise ... not quite a squeal, but almost.

And it refused to feed paper more than about an inch at a time. Pressing the paper feed button made it roll the paper about an inch farther down, stop, and squee again. Another press, another inch, stop and squee. Each time it seemed to advance the paper quite smoothly -- it wasn't slipping, jamming or feeding at an angle.

How do you google for a weird high pitched noise? I tried a few phrases in combination with epson c86 OR c84 OR c88 and hit several promising-looking URLs with domain names like fixyourownprinter.com ... but every hit turned out either to be someone describing a problem, then the discussion morphing into a discussion of unclogging ink cartridges, or someone describing a paper feed problem like mine and someone answering with unhelpful advice like "you could fix the mechanism if you could get the back panel off, but that's hard if you're not a printer repair shop and printer repair shops charge more than the printer is worth, so throw it away and buy a new printer."

I try to be green -- I recycle, turn off lights, try to use low power PC and monitor, and I'll be damned if I'm going to throw out a great big hunk of mostly nonrecycleable plastic every couple years without at least trying to fix it.

Giving up on web searching, I unplugged the printer and started pushing and poking at it to see what I could disassemble. The back cover clearly was tucked into the two side covers ... it clearly wasn't going anywhere until those side covers came off.

The side covers had several holes to the plastic piece underneath, with arrows near them seeming to invite "push and slide". But there didn't seem to be much consistency to whether I was supposed to push the outer cover, or the inner tab, in the direction of the arrow. I finally just ignored the arrows and used screwdrivers and pliers to poke and compress and wedge and slide until I got the left side cover (left as seen from the front of the printer) off.

The right side cover was more challenging -- I had all the tabs loose, but the cover seemed to stick at a point near the front, near the "Dura-Brite" oval. After twenty minutes of attempted finesse, I switched to trying to force it (since the alternatives were to throw the printer in the garbage or pay a repair shop more than the price of a new printer). I heard two sharp CRACKs as of plastic tabs breaking ... and the stuck front side popped loose. Curiously, I couldn't find any obviously broken plastic inside; forcing it was apparently the right and only way to get that side cover off.

[Epson with paper jam] Inside ... everything in the paper path looked fine. I pulled out an errant paper shard that's been floating in there for about a year (I knew right away when I fed that sheet of business cards with some of the cards already removed that it had been a bad idea) but it hadn't been touching any of the mechanism.

What's this on the left side, though? There was a tiny ink-smudged piece of paper between one of the pulleys and its toothed belt. Hmm. Doesn't look like it ought to be related, but it clearly doesn't belong ... so I pulled it out.

I poked and prodded and shone flashlights for a while longer, but couldn't find anything else. Darn! Well, just for the heck of it, I plugged the printer back in and switched it on. No squee tone! Hmm ... I fed it a piece of scratch paper and pushed the paper feed key ... and the paper went straight through, no noise, no fuss.

Whee! I hooked it up to the computer and tried a nozzle test (escputil -r /dev/usblp0 -mC86 -u -n) and it seems fine! The printer is back in its normal place now ... sans side covers, of course. I figure putting them back on so soon is just an invitation for the problem to come back. I'll put them back on eventually ...

The moral of the story is: don't let ignorance stop you from trying to fix things. Maybe the problem was that little piece of paper wedged in the wheel after all. Or maybe, as I often suspect, sometimes hardware just gets lonely and wants some attention ... and if you're willing to spend an hour dinking with it, it doesn't matter how little you know about what's actually wrong. All it really wanted was your attention.

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[ 14:12 Sep 13, 2008    More tech | permalink to this entry | comments ]

Fri, 12 Sep 2008

Linux Planet: Linux Astronomy part II: XEphem

I have a new article on XEphem on Linux Planet, following up to the KStars article two weeks ago: Viewing the Night Sky with Linux, Part II: Visit the Planets With XEphem.

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[ 11:50 Sep 12, 2008    More writing | permalink to this entry | comments ]

Mon, 08 Sep 2008

Turning off Firefox 3's whizzy drag images

Among Firefox 3's whizzy new features, compared to Firefox 2, is the drag images. If you drag from anywhere in the browser, instead of getting the little cursor-sized drag image following the cursor, you get a preview -- sometimes even a full-sized copy -- of what you're dragging.

It's really startling and neat and whizzy looking. Except ... when you're dragging and you have this large very pretty, and very opaque, image under your mouse, you can no longer see whatever should be under the image -- like the tab where you're trying to drop it.

After two or three weeks of never being able to drag a URL to another tab to open it there (I kept guessing where the tab was, guessing wrong and having it open as a new tab) I went exploring.

Fortunately it turns out they've provided an easy way to turn it off. Go to about:config and search for "drop". Find the line for nglayout.enable_drag_images and double-click it. Or add this line to your user.js or prefs.js:
user_pref("nglayout.enable_drag_images", false);

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[ 20:21 Sep 08, 2008    More tech/web | permalink to this entry | comments ]

Tue, 02 Sep 2008

DSLR Camera Foo

I thought it would never happen ... I've finally joined the Digital SLR world.

Why would it never happen? I enjoyed film SLRs for years ... from the Olympus OM-1 (great little manual camera) I had as a teenager to the Nikkormat EL and Nikon FG I used a decade ago. I only stopped because processing and scanning slides was such a hassle compared to the ease of uploading digital images. So why not a DSLR?

The problem was that when Nikon went digital, they orphaned all their old manual-focus lenses. They're still physically compatible (they'll screw on to the DSLR body), but peeved Nikon DSLR owners inform me (and camera store clerks agree) that the Nikon cameras won't meter with the old lens attached.

I don't mind doing my own focusing (manual focusing is one of the prime advantages of an SLR, not a disadvantage) but having to guess at the exposure setting too? "Oh, just carry a light meter," people say. On a camera that costs over $600? That bothers me.

So I was peeved at Nikon and not about to buy anything from them ... but meanwhile I had all these lenses, and hated to buy some other brand where the lenses wouldn't even screw on. So, no DSLR for me ...

Until I was pouring out my lens-mount frustrations during a camera discussion one night on #gimp and one of the regulars (thanks, Liam!) said "Well then, why don't you just get an adaptor that lets you use Nikon MF lenses on a Canon?"

A what? said I.

Sure enough, there are lots of them on Ebay ... search for canon nikon adaptor or look at Gadget Infinity's "lens adaptor" section. You can even (for a little more money) get a "confirm" lens that lights up the autofocus-confirm points in the viewfinder to tell you when the camera thinks you're in focus.

A few months passed (too busy to do camera research) but eventually I found the time and budget ... and now I have a 5-day-old Canon Rebel Xsi, which indeed takes excellent photos (correctly metered) through my old Nikon AI-mount Sigma 70-300 APO zoom macro. And the 18-55 kit lens (the equivalent of a 29-88 in a 35mm camera) isn't bad either -- a little slow (f/3.5 at the widest) but decently wide at the wide end (in the years of using pocket digicams I'd forgotten how much nicer it is to have a true wide-angle lens) and with a nice close focus for macros at the long end.

Even the autofocus isn't bad -- there are still plenty of times when I need manual, but the Rebel's autofocus is much faster and more accurate than any I'd seen on earlier cameras.

[The Canon says F00] It's such a great feeling to use an SLR again. The morning after the camera arrived, I looked up and saw goldfinches at the feeder just outside the window. I picked up the camera, switched it on, pointed, zoomed, focused and snapped. No worries about whether the camera might have decided to focus on the window, or the window frame, or the tree, or the bush -- just focus and shoot. What a pleasure!

And the best part: this must be a camera made by geeks, because when it has the Nikon lens attached ... it says F00!

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[ 20:59 Sep 02, 2008    More photo | permalink to this entry | comments ]