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* Posts by Frumious Bandersnatch

1283 posts • joined 8 Nov 2007

Stanford super runs million-core calculation

Frumious Bandersnatch
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Boffin

Re: Quite impressive in term of size but am I alone in wondering.

Shouldn't this SIMD thing just work by now instead needing lots of twiddling?

It's not just SIMD. Although the article doesn't state it explicitly, each of the cores models a small area of space and it has to communicate various outputs to neighbouring small areas of space. The clue is in the line The waves propagating throughout the simulation require a carefully orchestrated balance between computation, memory and communication. Amdahl's Law puts a brake on how well any real-world computation like this will scale up when run on a parallel (or SIMD) architecture due to the need for components to interconnect and transfer data between each other (such as propagating global force/pressure vectors after each local computation per simulation time quantum) . In this case, I'm sure a lot of their time spent "ironing out the wrinkles" was trying to get those inter-core messaging parts of the simulation humming. But there are other potential bottlenecks too that need to be looked at to prevent stalls/starvation too (ie, "computation, memory and communication" above). There's definitely not just a single "point and shoot" solution to parallel programming.

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Silly gits upload private crypto keys to public GitHub projects

Frumious Bandersnatch
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Re: @Frumious Bandersnatch

Thanks, Daniel B. It's nice to have that validated, even down to my guess that private and public keys don't store the same data . The downvotes I got are unimportant compared to that. Now if Lee Dowling had said that p and q were stored with the private key then I'd happily have conceded the point to him. Maybe he knew that and it's what he was trying to get at, but it's not what came across. I'll give him the benefit of the doubt and say we're all right. Except the downvoters. You still suck.

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Frumious Bandersnatch
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Re: but ...

No, they are not equivalent. Maths modulo high primes is the entire security BECAUSE it's not a mechanism that you can just reverse like that, and the private key is not "just a prime".

In general, the private key contains both the public key and some other large prime, whereas the public key is only a large prime (to get a simple analogy). The public key is actually derivable from the private key (that's how you MAKE a public key!) but NOT vice-versa (or PKE encryption would be useless). The private key contains extra, private information that should not be revealed and is not in any way derivable from the public key within a reasonable length of time.

OK, so I just happened to have Schneier's Applied Cryptography (2nd edition) on my desk as I read your post. I looked it up and confirmed that what I said earlier is correct. On page 467 it covers generating the public and private keys (which are multiplicative inverses of each other mod (p-1)(q-1)). Then it talks about encrypting and decrypting and finishes by saying "The message could just as easily have been encrypted with d and decrypted with e; the choice is arbitrary". That's exactly (and only) what I said in my post. I think you may need to brush up on how RSA encryption works. In particular, you can't derive either the public key from the private key, or vice-versa. Not without knowing the factorisation of pq, anyway. Nor does the private key contain "extra, private information".

Compound encryption schemes (involving RSA and something else) are a different matter, as you pointed out. But then, I never actually claimed that you could swap keys there and still have everything work.

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Frumious Bandersnatch
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but ...

isn't ((m ** private) ** public) mod pq = ((m ** public) ** private) mod pq? Maybe some of these users at least have just decided to swap public and private keys for each other? Maybe it's their secret "twist"...

OK, I'm not really serious. Most likely ssh (or pgp or whatever you use to generate keys and do the crypto) stores public keys in a different format to the private key so they're not interchangeable. But at least with the underlying RSA bit, calling one key public and the other private is just a matter of which one you actually reveal...

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Samsung posts RECORD profits, but execs drip cold sweat over 2013

Frumious Bandersnatch
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Re: Will

Will they now use some of their record profits to give the workers better conditions and rates of pay and stamp out child labour?

They're turning kids into slaves Just to make cheaper sneakers But what's the real cost? 'Cause the sneakers don't seem that much cheaper

Why are we still paying so much for sneakers ? When you got them made by little slaves kids What are your overheads?

(Think about it)

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Frumious Bandersnatch
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When Samsung lost their case against Apple

I said to myself, "self, you should really buy some Samsung shares."

Unfortunately, even though I talk to myself (quite a bit), I rarely listen to what I have to say.

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Brit 2.5-tonne nuke calculator is World's Oldest Working Computer

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what did it calculate?

I have it on good authority that it came up with "BOOBIES"

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Shiny, shiny! The window's behind me...

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those extra horizontal pixels rarely go to waste.

I like widescreen too, for the reasons already pointed out. I still find myself wishing for more vertical resolution too, though. Tabbed browsing in the webotron and gnome-terminal (and virtual desktops if you want to count that) already make great use out of screen real estate, but it would be nice to be able to see more lines of code in emacs or Eclipse or the like. Come to think of it, I guess there's always Ctl-x 3 in emacs if I want to look at a buffer in 2-up mode, providing I don't mind scrolling manually in each window. I must remember to try that next time.

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Frumious Bandersnatch
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Re: Shiny, shiny, shiny boots of leather...

Yup... definitely in that camp myself

♫ ... whiplash girl-child in the dark ... ♬

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Tablets aren't killing ereaders, it's clog-popping wrinklies - analyst

Frumious Bandersnatch
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There are those who believe

That "crisis" is just another word for "opportunity". If the problem is really that bad, I'm sure the book vendors will start a new "100 books to read before you die" campaign.

/HHOS

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Microsoft's Intel-powered Surface Pro to launch in February

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Re: ECT

Except he left out the bits about going to the bottom of the sea for bunk-beds. And the hooker. Can't forget the hooker. Almost as vital as ECT.

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Frumious Bandersnatch
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Re: I'm so excited

Hmm... you seem to have forgotten "and I think I like it"

Though judging by your last line, perhaps not.

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Mega launches with mega FAIL

Frumious Bandersnatch
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Re: Should be doable

Just break the encrypted files down into small enough chunks and you'll find dupes

If it were that easy, you could just break it down into 1-bit chunks. But that obviously requires a bigger index than the original file collection. (Q.E.D. by Reductio ad Absurdum). Random data (such as the output of a good encryption algorithm) by definition are not compressible.

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Frumious Bandersnatch
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Re: Deduplication, how?

It doesn't seem likely, does it? There's one type of encryption (homomorphic encryption) that in theory could work, but in practice it won't. I won't bore you with details of that.

The solution I would use would be to set up the front-end of the storage system to use an all-or-nothing transform (AONT) on the files, break them up into blocks and then distribute those blocks in a random order, with a single encrypted "key" being the locations and order of those blocks. So long as nobody can break into the fronted computer (or instruct it to divulge how to reconstruct a given file) then the storage is secure. Since the AONT should produce the same blocks for the same input file, you can do block-level dedup on the actual storage servers. I'd then encrypt the access key, add some validation info and send it back to the user before deleting it.

Of course, in this scheme, you (as a user) can't trust the server not to keep the access key or to make a copy before it's encrypted, and so on.

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TSA to pull backscatter perv scanners from US airports

Frumious Bandersnatch
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Re: wow!

Gah! Enough with the downvotes. I get it. I know, it's something I'll have to take up with my the- rapist.

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Frumious Bandersnatch
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wow!

They really called those things rapey-scans? (that's how I'd pronounce it, anyhow).

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Microsoft's ARM blunder: 7 reasons why Windows RT was DOA

Frumious Bandersnatch
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Microsoft seems to be a victim of [tablet] dynamics

It can't win and it can't break even. Unfortunately, neither can it break out of the game.

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VIA bakes a fruitier Rock cake to rival the Brit Raspberry Pi

Frumious Bandersnatch
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I got an Odroid-x and the hidden Fedex charges put it to > £120.

Similar story for my X2, but I did what the hardkernel website suggested and called my local customs office before placing the order. They told me about the extra "customs clearance" charge that Fedex adds in. I guess that hardkernel could have done a better job on pointing out the surcharge that Fedex puts on it, but I can't fault them on their advice on contacting customs. I still went ahead with the order once I knew about the extra costs. Well worth it, I reckon.

As for Atom vs ARM systems, I actually did a bit of window shopping before ordering the X2. To be honest I couldn't actually find any Atom systems that were as good or as cheap. The one thing that the bare-bones Atom systems did have going for them was standard (mini) ATX and SATA ports for upgradability. They're still quite expensive compared to the ARM boards. Also, buying a cheap 2nd hand system was out for me because I was looking for something with low power usage and you don't get that with older Intel/AMD/Atom stuff.

I guess that in the next year we'll start seeing more ARM SoC with SATA, USB 3 and gigabit ethernet since there's definitely a market for it. Until then I can definitely live with flash/USB2 and 100Mbit ethernet.

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Frumious Bandersnatch
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re: mk808

An mk808 is less than half the price, runs a newer version of android and is WAY more powerful.

I'd never heard of it, but the link you gave puts the mk808 at $58.99, which isn't "less than half the price" of either the Rock ($79) or Paper ($99).

Now the ODROID-U2, on the other hand, costs $89 (*), has quad core clockable to 2GHz (base 1.7GHz) and 2Gb of RAM. Also runs Jelly Bean and Linaro Ubuntu (no accelerated X yet, though it's expected in a few weeks). Its sibling product, the ODROID-X2 is very similar, except that it costs $135 and has a whole lot more ports.

(*) as with a lot of these boards, power supply, cabling, flash drive and shipping aren't included. A full U2 ends up costing about $150 (including a hefty $40 shipping fee from Korea), plus local customs clearance and VAT which brings it to something closer to $190. Definitely pricey compared to a Pi (which comes to around €72 all told), but the U2/X2 are are at least 12 times more powerful in my tests (thanks to 4x cores, 2x speed, step up from ARMv6 to ARMv7). So while the Pi definitely wins out on price/system, the ODROIDs definitely win out on performance/price IMO.

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Pubic louse falls victim to eager Brazilian strippers

Frumious Bandersnatch
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Re: Someone

Aww, I'm sure they are to other crabs!

Well it's not crabs as such, but this Southpark episode is hilarious. The "The Thing" thing they did cracked me up.

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Frumious Bandersnatch
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Re: It's not all good though

I think the word you were looking for is 'depilation'.

The way I misread that ("delepidoteration"), I thought he was talking about getting rid of butterflies.

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You know flash is king when disk giant Seagate grows its SSD line

Frumious Bandersnatch
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busy OLTP database server

Although I don't have any direct experience with this, it seems that a lot of databases aren't well suited to using flash storage due to them not being optimised for that medium. The problem lies in the way that inserts and updates often have to make several updates on the on-disk indexes (B-trees or whatever) and each random write requires a read-blank-rewrite cycle on an entire disk block. Reads from the database, on the other hand, is something that does suit flash well since seeks are effectively free.

I don't have a link to any recent papers to hand, but if you search for "log structured database flash" you should turn up a few. The main advantage of log-structured databases is that inserts and updates only have to write once to the disk (with periodic rewrites for garbage collection to coalesce partially empty blocks). Thus you get very good write speed and since you're not going through as many of the read-blank-rewrite cycles that are typical of B-tree style indexes you should be able to extend the life of the disk by three times or more. Have a search for Fast Array of Wimpy Nodes (FAWN), too. It's slightly old, but it gives a good demonstration of the kind of speedups that log-structured databases + flash storage can achieve.

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Scientists spin carbon nanotube threads on industrial scale

Frumious Bandersnatch
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Re: Pb?

If he's normally researching lead, what qualifies him to talk about carbon?

For his next breakthrough ... a [carbon nanotube] Zeppelin.

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Review: Google Nexus 4

Frumious Bandersnatch
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Re: A bit of a spanner?

re: Ah. Passers by asking people stupid questions of people who are taking pictures in the street.

I disagree... I actually got quite a warm feeling on reading that part of the article. Nice to see that a passer-by would take the time to see if he was OK. And lets face it, taking photos by spinning around probably does look a bit crazy if you don't know what's going on.

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Ten stars of CES 2013: Who made the biggest splash?

Frumious Bandersnatch
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Re: Curved monitors

Do it on the cheap:

http://paulbourke.net/dome/mirrordome/

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Reg Hardware Awards Best of 2012: VOTING NOW OPEN

Frumious Bandersnatch
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Wow.. this time of year again

Is it really the third year in a row that I've had to vote for Ubuntu as the worst product of the year?

(I say this not as a Linux hater, but as a fan, fwiw)

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'Doomsday' asteroid Apophis more massive than first thought

Frumious Bandersnatch
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2036?

So we just have to survive another two years after that until the real end of the (Unix) epoch kills us all then?

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Boffins hide messages in Skype ‘silence packets’

Frumious Bandersnatch
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TIMTOWTDI (ENOC)

There Is More Than One Way To Do It (encoding "nothing", of course)

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Bite us, Apple: Samsung hauled in $8.3bn in Q4

Frumious Bandersnatch
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Re: They should feel so proud

re: Copying another company to make 8Billion.......I feel proud for them!!

As it says in the article headline: bite me.

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'SHUT THE F**K UP!' The moment Linus Torvalds ruined a dev's year

Frumious Bandersnatch
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Torvalds insisted he was a mild-mannered man of peace

Poppycock! He's a git:

Torvalds said: "I'm an egotistical bastard, and I name all my projects after myself. First 'Linux', now 'git'."

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Yes, hundreds upon hundreds of websites CAN all be wrong

Frumious Bandersnatch
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re: "you eat x spiders a year while you sleep"

Or the one about how the daddy long-legs (crane fly) is the most poisonous creature in the UK/Ireland, and has venom that can kill a man. Only fortunately for us, it can't bite through our skin...

(yes, this is a myth, but a very often repeated one).

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Frumious Bandersnatch
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Re: 6/8 time...why not 3/4 time?

Apparently it's down to the fundamental note length not being 1/4 note, but half as much again, ie, 3/8ths (a dotted quarter-note in sheet notation). Three/Four time is typical of waltzes and has a ONE two three and ONE two ... beat structure, but I'm not sure how to describe how 6/8 time sounds, or even whether it necessarily has a fixed place to place the emphases.

Anyway, while reading this article, quite a few thoughts came to me. Several posters have brought some of them up already, but not all..

re: the xkcd strip... is the word order even right in that?

http://itre.cis.upenn.edu/~myl/languagelog/archives/005424.html

re: "kiss this guy" I believe (I read it somewhere on the Internet :) that Hendrix became aware of this mishearing and on some occasions actually sang the modified lyrics. Certainly one time I saw him on a BBC program it sounded more like "kiss this guy" than "kiss the sky" to me. Also, this:

http://en.wikipedia.org/wiki/%27Scuse_Me_While_I_Miss_the_Sky

I loved The Smiths, but lots of their lyrics were indecipherable to me... "horn-shoed bicycle on a hillside desolate???" And forget about My Bloody Valentine....

Getting back to time signatures, I hope you mentioned Time Out by the (sadly) recently-deceased Dave Brubeck. While he didn't write the famous Take Five with its 5/4 time signature, all the tracks on the disc have unusual time signatures. It still sounds great today...

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Major new science: WOMEN MORE NUDE more OFTEN online

Frumious Bandersnatch
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Re: Goodness gracious

... while the [male] hero is either armoured head to toe or has the whole 'loincloth and a big chopper' thing going on.

Well if his chopper was called Brainbiter, then sometimes he'd go "sky clad" too.

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The LINUX TABLET IS THE FUTURE - and it always will be

Frumious Bandersnatch
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Re: I still don't get…

Apple and Linux representing diametrically opposed design philosophies

Exactly that. Linux carries on the free and open aspect of Unix history, while Apple carries on the parts with all the litigation over copyrights, trademarks and such. OK, so the latter isn't actually anything to do with Unix as such, but it's a problem that has dogged Unix-like systems ever since people realised that it is actually valuable. At least Linux (and I guess the free BSDs to a lesser degree) managed to make most of the legal wranglings moot, apart from the SCO issue.

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Dead Steve Jobs' mega yacht seized by testy Philippe Starck

Frumious Bandersnatch
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Coat

but who would want ...

that iSore?

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MIT boffins demonstrate NEW form of magnetism

Frumious Bandersnatch
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Re: excited states apparently exist in a contiuum between quantum states

that kind goes opposite to the meaning of quanta, doesn't it?

Yeah... "fractionalised quantum states" had me my scratching my head too. At least the article does a good job explaining why it's weird (and controversial).

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Opposable thumbs for FISTS, not finesse, say bioboffins

Frumious Bandersnatch
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Re: QED

Or to mangle a Billy Bragg quote... "something that every football fan knows, it only takes five fingers [if you include an opposable thumb as the fifth, it seems] to form a fiiiist"

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Canadian man: I solved WWII WAR HERO pigeon code!

Frumious Bandersnatch
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Re: And these idiots at GCGQ are going to ...

Perhaps you mean mean?

Or, to use a word that cropped up in an article here on the Reg just a few days ago, niggardly.

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Little spider makes big-spider-puppet CLONE of itself out of dirt

Frumious Bandersnatch
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Re: Counting spiders

Seems unlikely they could count to 8

Maybe they can count to 256?

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Frumious Bandersnatch
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Re: Not so original

You should build yourself a Pantograph (or a series of them) and connect it up to an oversized model of yourself. That should scare the bejesus out of the boss so he won't come around ever again.

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Frumious Bandersnatch
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Re: So, presumably

I don't think it needs self-knowledge

I'm not disagreeing with this, but I'm not sure you can completely rule out the idea that the spider is "deliberately" making something in its own self image. I'm not suggesting it has self-cognition (some insects and arachnids have brain cells running into the dozens, from what I read), but I don't think it's crazy to suggest that spiders can have a sense of proprioception (ie, knowing roughly where its limbs are) and that that might form the basis for setting up a feedback loop (from cybernetics) to explain the how of what it does, if not the why.

It would be pretty amazing to find that if could use visual information, but I'm guessing that proprioception could be a sufficient mechanism to explain it. It might even be possible to test the theory by filming the thing making the shape. If it makes leg waggles that correlate with the order that it builds the legs on the model then maybe the theory itself (to pardon the pun) has legs.

Just throwing this out there. IANAEB (I Am Not An Evolutionary Biologist).

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Frumious Bandersnatch
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Re: Brilliant

Like when atheists point at parasitic wasps as 'proof' there is no God? Equally weak arguments.

For some strange reason after reading this exchange I had the image of a little spider cackling maniacally and then booming out "Where is your God now?!"

I, for one, welcome out new marionette-wielding insect overlords, etc....

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Frumious Bandersnatch
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ISO 8601

Upvote for saying what I suspected, that you have to have the YEAR in front. Not only that, but the got the poster delimiter wrong too (slash instead of dash).

For some reason it really bugs me to see web pages using the MM/DD format for things like, eg, release dates. You have to figure out if it's just another typical USA-ism. It's not just the date format, which I guess their entitled to, but the fact (calling it this based on prima fascie evidence) that they never bother to think that they might have readers outside the US or that they might do something different there.

Whenever there's any doubt I always try to spell dates out as YYYY-MM-DD (props to Japan for having this as their standard) or spell out the date ("21st Dec" or "Dec 21"). And of course for anything computer related (eg, file naming) big-endian YYYYMMDD is almost always the correct order (adding dashes to taste).

Anyway, what has all this got to do with 4?

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Fish grow ‘hands’ in genetic experiment

Frumious Bandersnatch
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Dear El Reg

Do you got a number for that chick in the photo? Thanks!

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Ray Kurzweil to become Google's top engineer

Frumious Bandersnatch
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Re: I wonder if ...

re: billion node cloud...

You keep mentioning that here. Care to mention how it fares in the face of Amdahl's Law?

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Wind, solar could provide 99.9% of ALL POWER by 2030

Frumious Bandersnatch
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Re: Ummm... this is a MODELED finding?

Oops. I just reread the article and I see the point you were making about greatly reduced costs. It was late and I guess I glossed over that entire sentence/paragraph just reading is as "all without government subsidies". Sorry about that.

Still, I'm heartened by what another commenter said above that the assumptions might be reasonably realistic for the US states the model was looking at, even if it's probably not applicable here in the west of Europe. It's nice to get some positive news on this whole issue, even if it is only applicable there.

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Frumious Bandersnatch
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Paris Hilton

Re: Ummm... this is a MODELED finding?

I'm not sure if this is how they did it, but when I read "28 billion combos" my first thought is that it's probably easy to arrive at this solution by using a genetic algorithm. Probably more likely that they had some big, un-environmentally friendly compute cluster brute-force searching the entire solution space, though :(

I'm not sure how to react to your criticism of their models, to be honest. Yes, models can be unrealistic, but on the whole I'd rather have them than not. Then you can start picking apart the basic assumptions (the one you mentioned "renewables will drop greatly in price" wasn't even in the article text, so I don't know if you're just making that up or not) or otherwise criticise/falsify it. But to what end? Just to be negative, or to make a better model? In either case you can't criticise a model just for being a model...

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John Lewis agrees to flog Microsoft's Surface RT tablets

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Re: Demand has been phenomenal.

Do doo-da-doo-do.

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iPad mini to outsell iPad, get Retina Display? iPad to slenderize?

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Big Brother

Keep the [Aspidistras Flying]

Haven't read it, but Down and Out in [Paris and London] is pretty good. I'll always remember what he said about the quality of cutlery in a restaurant (that and forgetting that he had a gas bottle he could return when he was stony).

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