'Tis the season to rebuild eMacs

7 January 2009 — dan

My biannual eMac-rebuilding ritual.

Last time, I killed my mum's Mac on Christmas day.

I was a little late this time. It took me until yesterday.

Well, technically Anne did it this time, but only by doing the same thing I did two years ago, which is exactly what I would have done if I'd been the one sitting in front of the computer, because I had forgotten what happened last time.

Heck, I wasn't sure what even caused the problem last time. Only now that it's happened twice do I have some degree of confidence about it.

Word to the wise: If your mum's got an eMac with OS X Tiger on it, and she's just clicked the cancel button every time the computer said there was an update it'd like to install, and you eventually sit down in front of the computer and say "yes" to the literal years of updates that're all waiting to be installed... then that eMac will go horribly wrong.

Perhaps the updates would have installed OK if we'd done absolutely nothing with the computer while they were installing. Including just clicking the "stop" button on the updater so we could make a backup first, which ironically seems to be what touched the problem off this time.

(Apparently the current version of OS X shuts everything down before it updates. I suspect there may be a connection between this problem and that feature.)

The computer looked, at least, less broken this time. No scary boot-up screen colours, just a power-on to usable-desktop time of about 30 minutes. But it still wasn't fixable on site.

(Which xkcd comic was it that showed the traditional "solving a computer problem" flow of activity? [UPDATE: Naturally, a reader found it for me almost instantly.] You know - you start out working on the problem, then trying to solve the problems your attempt to solve the problem caused, then just trying to get it back the way it was, then admitting that the fire has claimed the house but you think you might still be able to save the garage...)

So I'll be visiting Mum again later today. Provided the gigaton of updates currently trickling into the reinstalled OS don't pole-axe it again, of course.

Posted in Nerdery. 25 Comments »

Comics Versus Physics

29 December 2008 — dan

I just wrote this in response to a question on Ask Metafilter. Might as well get a blog post out of it, too.

The question was whether a super-strong superhero could actually shoot down fighter jets by throwing things, in this case coins, at them.

Thanks to lousy writing, superheroes often seem to warp space-time around them to let them achieve things that even someone with their powers should not be able to do. Throwing stuff at ultra-speed is one of those things.

Superman, like several other Flying Bricks, has super-speed as well as super-strength. So he, or a speedster like the Flash, could plausibly throw a rock, a coin, or a cupcake for that matter, fast enough that it'd punch a hole through, or just violently annihilate, any non-superpowered object it hit. The thrown object might just be a cloud of superheated gas by the time it hit the target, but it'd still do the damage.

(See also Superman's mysterious breath powers - super-blowing, and super-cold-blowing. His ability to blow up a typhoon on demand is strange - where's all the air coming from? The comics give some cock and bull story about how his lungs can compress the air they contain - thereby explaining the cold breath, because as air decompresses it becomes cold; never you mind why he doesn't blow cold all the time, or where the heat from compressing the air went. How cubic kilometres of air get into Superman's lungs in the first place also remains unexplained.)

Lots of superheroes are super-strong but only able to move at normal human speed, though. Rogue is one of those; she's got a few Flying Brick powers she soaked up from Ms Marvel, but I don't think those include super-speed. Characters like this may be able to throw a 40-kilo dumbbell as far as a baseball pitcher can throw a rock, but they shouldn't be able to turn bullet-ish objects into actual de-facto bullets, because you can't throw anything any faster than you can move your hand.

Heroes that can fly could fly at top speed and then fling something ahead of them at top-speed-plus-throwing-speed, but you've got to be super-tough to fly super-fast without dying if you hit a bird - another point that's glossed over in most comics. If you're super-tough, you'd think you could just fly through the target rather than toss mundane objects at it.

Super-strong heroes could also throw heavy things much faster than they could by hand if they used an appropriately strongly-built sling-like device. But that'd give them an attack like a 18th-century cannon, not like a handgun.

Yes, I do spend quite a lot of time thinking about things like this. Doesn't everybody?

Posted in Nerdery, Science. 17 Comments »

Die Legoroboter

21 December 2008 — dan

(Via.)

Most videos of Lego Great Ball Contraption modules are a bit hard to follow, but this one concentrates on only three modules, so you can get an idea of what's going on.

(The string-quartet Kraftwerk is nice, too.)

The Great Ball Contraption is basically just rules for ball-moving modules that make sure they can connect to each other - like a Technic version of the Lego Moonbase standard.

(Incidentally, you can fmt=18 this clip to get the higher-quality MP4 version, but fmt=22-ing it only seems to give you the basic FLV version at the moment. It doesn't fall back to 18. I knew there was some reason why I didn't do what the cool kids do.)

Posted in Hacks, Nerdery, Toys. 2 Comments »

Now carve a golf club out of it

20 December 2008 — dan

Behold, Theodore "Periodic Table Table" Gray's most recent Popular-Science-column adventure:

Making titanium from paint-pigment titanium dioxide, via a thermite reaction.

You're meant to put your reaction-vessel flower-pot inside a bigger pot with sand between them, so that the inevitable cracking of the pot won't allow the metal to escape. But it's more photogenic this way.

You also have to cheat a bit to get molten titanium to drip out of a titanium-dioxide/aluminium reaction. The reaction doesn't actually burn quite hot enough to melt the titanium, so it'll just give you a block of titanium-plus-aluminium-oxide slag. To avoid this, you put in extra aluminium, plus an oxidiser to get it to burn. In this case, the oxidiser is humble calcium-sulfate plaster.

And presto, a puck of pretty crystalline titanium can be yours.

(And yes, fmt=22 works on this video clip, giving you a 71.8Mb HD file which you can craftily download.)

Posted in Nerdery, Science. 3 Comments »

The Gamer Product That Will Not Die

20 December 2008 — dan

I reviewed the Mouse Bungee in July, 1999. And it wasn't brand new then. It's got to be ten years old by now.

It's been on sale at Aus PC Market for all of that time. They're still using the crunchy product pic I took with my DC120 in 1999, too.

Mouse Bungee

And now it's on special, yours (if you live in Australia) for $AU19.80 delivered! That's only slightly more than half what it cost when I first reviewed it!

Australian shoppers can click here to order one.

(It's too late for Christmas, though. AusPC go on holiday after Monday the 22nd of December, and they've already shipped their last 2008 orders; you can order stuff whenever you like, but your order will be charged and dispatched in January. AusPC also find it annoying when I tell people to buy things that're on special. So, uh, buy some other stuff, while you're there. I suggest you get a Core i7 PC, plus a spare in case you scratch the first one.)

If you, like me, still have a mouse with a cord, the good old Mouse Bungee really is not a bad solution to the cord-tugs-on-mouse problem.

All you really need to do to deal with that problem, of course, is to tape the cord to your desk at an appropriate point, or attach it to a heavy thing. WireWeights were the fanciest way of doing that second trick, but the company disappeared a couple of years after I reviewed their product in 2004.

The Mouse Bungee people and their surprisingly useful sproing-y product are still very much alive, though.

(Regrettably, the Batterylife Activator people have also vanished. You can still buy a Wine Clip, though, and I'm pretty sure the EMPower Modulator is still on the market, too.)

Posted in Nerdery, Toys. 5 Comments »

If you download only one 188Mb MOV file today...

19 December 2008 — dan

...make it World War, by Vincent Chai (via).

The high-res MOV version is right there on Chai's site, which could get just a leeetle bit overloaded in the near future. One thousand bonus points for the guy, though, for making that high-res version available.

Usually, you find some awesome short film on YouTube or Vimeo or wherever, and then you go to the creator's site, and there's nothing there but the same squished-down Flash-video version. You can format-equals-18 it on YouTube so you can download a better-than-nothing MP4 version, but that's it.

Vincent, though, has the whole HD enchilada right there for download, like the Code Guardian guys who inspired my last post like this. And like the Exploratorium guys with The Secret Life of Machines, for that matter.

Here's a direct link to the MOV file, which if you're reading this some time after I wrote it will either be nice and fast, or broken:
WW_VincentChai.mov

I hope he puts it on archive.org or makes a torrent or something. I e-mailed him about it, but have not yet received a reply, possibly because he's got better things to do than hover by the computer waiting for e-mails from me, or possibly just because it's the middle of the night where he is.

(See also.)

Posted in Humour, Movies, Nerdery. 3 Comments »

Dis way. No, dat way!

18 December 2008 — dan

I would have mentioned this earlier, but the excellent Illusion Sciences blog went over its Google Pages hosting quota, so I couldn't snag myself a copy of the SWF file to host on my own site.

Now the blog's back, so here it is:

Brilliant, huh?

More info at Illusion Sciences.

(See also.)

UPDATE: Here's a nifty HTML5 version of the same illusion, as per caerphoto's comment below.

Posted in Hacks, Nerdery, Science. 16 Comments »

Pushing a wombat down a garden hose

17 December 2008 — dan

Jeff Atwood's new post about Easy, Efficient Hi-Def Video Playback does not, in the final analysis, find that there's anything all that easy about it. But it reminded me of one of my own pet peeves.

I watch a lot of game-promo video clips, because my ISP has a nice fast mirror of the GamersHell archive that doesn't count toward my download allowance. So what the heck.

Many of these clips have an outrageously high bit rate. It's not at all unusual to see a clip that's less than three minutes long, but more than 400 megabytes in size.

The download time, I don't much care about. I just leave FDM ticking away in the background, with its download speed restricted if I want to get stuff done at the same time. But it irritates me considerably when I finish getting some whole-CD-sized video clip that I then can't even play, because its 600Mb bulk encodes only 2.3 minutes of video, which means the data rate is so tremendous that my computer chokes on it and I only get to see one frame out of 50.

VLC does a pretty good job on the more obnoxious files, especially when they're QuickTime format, the bane of Windows video viewers. But sometimes all the decoder-tweaking and task-priority-boosting in the world just can't cut it, because the people who made the clip decided to slide the "Quality" control to 150%.

Game PR people: Stop doing this!

I assure you that a mere 100Mb per minute is quite adequate to promote your product!

See all those pirated TV shows? See how 43 minutes of great-looking 720p video only takes up 1.1Gb? Are any light bulbs going on in your tiny minds?

(Sometimes a video manages to consume 300Mb a minute, and not even look good. I swear - I've seen composite-video-resolution clips with a giant black border all the way around that still had the kind of data rate you expect from an IMAX demo reel.)

UPDATE: Here's a magnificent example that I just discovered in my folder full of unwatched game vids. It's a promo video for the Battlezone-y Tank Universal, called TeaserSound02_2.mov. The clip is 36 seconds in length, and has a resolution of 640 by 480.

It is nine hundred and fifty-five megabytes in size.

That's 26.5 megabytes per second. A ninety-minute movie would take up 140 gigabytes at this data rate.

How did they manage to achieve this? Easy. Somebody just forgot to compress the video, or the audio for that matter, at all!

The clip has uncompressed CD-quality PCM audio, but that only accounts for 172 kilobytes per second (two channels times 44,100 samples per second times 16 bits per sample). It's the video that's the real heavyweight - 640 by 480 pixels, times 24 bits per pixel, times 30 frames per second. Hey presto, that's exactly 900 kilobytes per frame, and 27,000 kilobytes per second.

At least this means I must not have spent too much time downloading the clip. All GamersHell clips are zipped, which usually reduces their size by only a couple of per cent but which also stops people from using the GamersHell download servers as streaming video sources. Even high-speed light compression can get this clip down to 10% of its uncompressed size, though.

Posted in Nerdery. 18 Comments »
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