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Comments

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Quiet Cooling With a Copper Foam Heatsink

TeknoHog Re:I am skeptical (163 comments)

In other words, if you use the same volume of copper and the thickness of the fin is half the diameter of the sponge cylinders, you have the exact same surface area. The thinner fins may be weaker, but since the additional fin material on the sides reinforces the structural strength, I assume that's not too big a deal.

I agree with the rest of your argument, especially including the fluid flow part. However, I'm not sure if this part works out, it really depends on other assumptions. For a point load I agree -- the load is spread across the width, at least to some extent. But with a wider surface, you generally experience more load, proportional to the size, and there's no benefit in connecting the fin segment to neighbouring segments. So the cylinder would be stronger in this sense. It's the intuitive idea of increasing the width in the direction of the load, and the other direction won't help.

yesterday
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Quiet Cooling With a Copper Foam Heatsink

TeknoHog Re:As Flammable as Steel Wool? (163 comments)

Simply by looking at the reactivity series, you can tell that copper is considerably less flammable than iron. OTOH, powdered copper burns with a nice green colour when tossed into a Bunsen flame.

For a practical standpoint, you could ask if steel wool burns in the temperatures of a CPU heatsink. Probably not, and this copper sponge is much less of a risk. Of course, if you like living on the edge, and tweaking CFLAGS is not enough, try an entire case made of a notoriously reactive metal.

yesterday
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Quiet Cooling With a Copper Foam Heatsink

TeknoHog Reynolds number (163 comments)

basically means that for slower airflow, you need larger gaps for air to flow through. This is why the sponge is bad for heat dissipation, and great for insulation. It's kind of intuitive, but it's nice to have some science backing to it. Having a large surface is good, but it doesn't help if the airflow across the surface is limited.

On a side note, I've been on a quest for quiet cooling since the very early 2000s, incidentally after getting a physics degree. It's mostly in the last couple of years that I've started to see really sensible coolers in the general market. For example, the usual CPU cooler in the olden days had a fan pushing right against the CPU with minimal fins in between, meaning there's a considerable high-pressure centre with no airflow. No one with a fluid mechanics 101 would design crap like that. OTOH, the traditional CPU/mobo setting is a little problematic; first you put the most heat-concentrating element in the middle of everything, and then later you realize it needs cooling. (I'd put the CPU socket on the reverse side and use the case as a huge heatsink...) Now finally the designers have the sense of using a straight sideways airflow, combined with heat pipes. Why the fsck did this take so long?

I used to strive for pure passive cooling, but in the end I don't mind a large, slow fan -- it's enormously better than no fan, and still indistinguishable from other background noises. This is another nice thing to see in cooler designs, from the 1-inch whiner in my first Linux laptop to the 140-mm quiet giants that can easily manage a couple of hundred watts of GPU.

BTW, if you ever need to explain somebody how a heat pipe works, take them to a sauna.

yesterday
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Suddenly Visible: Illicit Drugs As Part of Silicon Valley Culture

TeknoHog Re:Ban caffeine! (506 comments)

Not only that, they are addicted to DHM. Addiction is bad, mmmkay?

3 days ago
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Suddenly Visible: Illicit Drugs As Part of Silicon Valley Culture

TeknoHog Re:Ban caffeine! (506 comments)

You could ban all of those drugs, and some other drug would become the first one users try.

Would that be causation, or just correlation?

3 days ago
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Suddenly Visible: Illicit Drugs As Part of Silicon Valley Culture

TeknoHog Ban caffeine! (506 comments)

It's a gateway drug!

3 days ago
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Ask Slashdot: What Would You Do With Half a Rack of Server Space?

TeknoHog Re:Pushing this even further... (206 comments)

Pushing this even further --- I have inherited a (mostly empty) 3,000 square foot data center (almost Tier III - but it shares a wall with the outside or so I'm told). I'm using (maybe) two racks.

Are you a Nigerian prince?

4 days ago
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Ask Slashdot: What Would You Do With Half a Rack of Server Space?

TeknoHog Re:Crypto! (206 comments)

Yeah, CPU-only coins last for about 48 hours before a GPU miner is released. As far as crypto-coins the fact is, a modern graphics card is faster than almost anything a CPU can do.

This applies mainly to those that simply choose a semi-standard hash algorithm, such as one of the SHA3 contestants or a combination thereof. Often there is GPU code already available, and building the miner is all about reading some specs and writing some glue code*. Also, most of these coins are based on Bitcoin and simply change the hash algo.

However, most Cryptonote coins (using the Cryptonight algo) have lasted for ages without an open GPU miner. For starters, they are not forked off Bitcoin. Boolberry is a Cryptonote coin with a different algo, which makes it faster to sync, while still aiming for GPU resistance. An open GPU mining codebase was released just a few days ago, and there's still work to do for general distribution. Besides, Boolberry's algorithm needs several MB of fast cache, which is OK with GPU texture cache at the moment, but it will grow over time, possibly making GPU mining unfeasible again.

*(I wrote a GPU miner for JH-256 coins in a few days with no prior GPU/OpenCL experience. Endianness is a bitch.)

4 days ago
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Ask Slashdot: Where Do You Get (or Share) News About Open Source Projects?

TeknoHog Re:various places (85 comments)

The Bitcoin 0.3.0 release article on Slashdot in July 2010 changed my life. For example, by getting me into FPGA and GPU hacking.

4 days ago
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Linus Torvalds: "GCC 4.9.0 Seems To Be Terminally Broken"

TeknoHog Re:Great. Now the sloth community... (728 comments)

If only there were a dedicated community for every sad sloth, or at least an anagram thereof.

(If you either feel for the sloths, or just appreciate the pun, please send a random amount of slothcoins to SML12GaoebyneT7ctYuj9PFicptetjPUct. Thank you.)

4 days ago
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How Stanford Engineers Created a Fictitious Compression For HBO

TeknoHog Re:Meh (89 comments)

Or if you're into math, you invoke the pigeonhole principle So the limit of useful compression (Shannon aside) comes down to how well we can model the data. As a simple example, I can give you two 64 bit floats as parameters to a quadratic iterator, and you can fill your latest 6TB HDD with conventionally "incompressible" data as the output. If, however, you know the right model, you can recreate that data with a mere 16 bytes of input. Now extend that to more complex functions - Our entire understanding of "random" means nothing more than "more complex than we know how to model". As another example, the delay between decays in a sample of radioactive material - We currently consider that "random", but someday may discover that god doesn't play dice with the universe, and an entirely deterministic process underlies every blip on the ol' Geiger counter.

IOW, Kolmogorov complexity. For example, tracker and MIDI files are a great way to "compress" music, as they contain the actual notation/composition rather than the resulting sound. Of course, that doesn't account for all the redundancy in instruments/samples.

So while I agree with you technically, for the purposes of a TV show? Lighten up. :)

IMHO, half the fun of such TV shows is exactly in discussions like this -- what it got right, where it went wrong, how could we use the ideas in some real-world innovation. I find that deeper understanding only makes me enjoy things more, not less, and I enjoy "lightening up" my brain cells.

5 days ago
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How Stanford Engineers Created a Fictitious Compression For HBO

TeknoHog Re:Meh (89 comments)

Or if you're into math, you invoke the pigeonhole principle.

5 days ago
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Buying New Commercial IT Hardware Isn't Always Worthwhile (Video)

TeknoHog Re:Slashvertisement? (92 comments)

I'm sorry if you missed my point. I agree that USB 3.0 is faster than USB 2.0 — in the same way that PCI Express is faster than PCI. Does that mean PCI has gotten much faster, or is PCIe a new interface that has replaced PCI?

about two weeks ago
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Buying New Commercial IT Hardware Isn't Always Worthwhile (Video)

TeknoHog Re:Slashvertisement? (92 comments)

In the past few years, USB has gotten much faster

I agree with most of your post, but this is simply false. USB 3.0 is a completely new interface, bolted on USB 1/2 to make it seem like a seamless transition.

I used to think USB is all about selling a new interface with an old name. For example, in a few years we'd have a CPU socket called USB 14.0, but hey, at least it's USB. Now I have a USB 3.0 hard drive, and the mini plug/socket in particular shows how it's just USB 1/2 + 3.0 bolted together. So my new future prediction is USB 17.0 where you have this fist-sized lump of connectors from different ages, all tied into one bunch to ensure backwards compatibility.

BTW, I have two Intel Core CPUs here, Core 2 Duo T7200 (released 2006) and Core i5 520M (2010), both "mobile" CPUs. The former is a lot faster under certain workloads. In practice, they are roughly equal, and the new one probably has better power efficiency, but it's not exactly the level of progress I'd expect.

about two weeks ago
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CCP Games Explains Why Virtual Reality First Person Shooters Still Don't Work

TeknoHog Re:Karma to burn so fuck you. (154 comments)

I could have let this one slide, but I have a few things to say:

1. Darl, Darl McBride, is that you? When will you be testifying against Mark Shurtleff and John Swallow?

Is that an African or a European Swallow?

about two weeks ago
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Dell Starts Accepting Bitcoin

TeknoHog Re:No Doge? Much sad. (152 comments)

If you want to use Doge to pay for computers, there's at least Bitelectronics. I have no connection to them except being a happy customer (in the same country though, I can't speak for their international shipping).

about two weeks ago
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Sexual Harassment Is Common In Scientific Fieldwork

TeknoHog Re:Newsflash! (362 comments)

Now please send your $50,000 worth of research grant funding to my bitcoin address: FJi2seXY2jf9eYEDoit4ScienCEFiJSfj82jfiffj

You could at least use a real BTC address, in case someone accidentally you some coin. That's not even a Grøstlcoin address (they start with an F).

(By reading the above, you agree to send a random amount of BTC to 1Guy1JarSpEhxb94VYMYRvTMhqbAgdnCtL as a consultation fee. Thank you.)

about two weeks ago

Submissions

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Startup by ex-Nokians will keep Meego phones alive

TeknoHog TeknoHog writes  |  about 2 years ago

TeknoHog writes "A team of former Nokia employees behind the N9 has revealed plans for an upcoming Meego phone. According to the press release, "Jolla Ltd. will design, develop and sell new MeeGo based smartphones. Together with international private investors and partners, a new smartphone using this MeeGo based OS will be revealed later this year.

Jolla Ltd. has been developing a new smartphone product and the OS since the end of 2011. The OS has evolved from MeeGo OS using Mer Core and Qt with Jolla technology including its own brand new UI.""

Link to Original Source
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Microsoft worms to patch software

TeknoHog TeknoHog writes  |  more than 6 years ago

TeknoHog writes "According to New Scientist, Microsoft researchers at Cambridge, UK are studying the use of computer worms for spreading software fixes and fighting malevolent worms. From the article: "Software patches that spread like worms could be faster and easier to distribute because no central server must bear all the load." Not that there aren't other ways to avoid the server bottleneck, even from Microsoft itself."
Link to Original Source
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TeknoHog TeknoHog writes  |  more than 7 years ago

TeknoHog writes "European scientists have developed a system for tracing the position of fingers on any surface. From the New Scientist article: "Two or more sensors are attached around the edges of the surface. These pinpoint the position of a finger, or another touching object, by tracking minute vibrations. This allows them to create a virtual touchpad, or keyboard, on any table or wall.""

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