2569 posts • joined 24 Apr 2007
Cheers to him
Every time I see the ISS fly over (happens quite often whilst stargazing, I could even spot its overall shape with big binoculars), I just have to give quiet praise to the people up there, and the people who helped put them there. However we bemoan not doing enough space exploration, some people are dedicating and even risking their lives in the name of space exploration.
People like Cmdr Hadfield set a shining example in my book. Cheers to him and all like him
Re: Latency, it's all about latency
CSP is powerful. The main problem I find is in keeping communication down, especially in terms of how often processes need to communicate. It is much cheaper to have a few large chunks shuttled from on process to another, than it is to have a whole lot of little messages. It is not just the latency in that case (it also plays a role), but it is also the synchronization that costs time (barriers are particularly costly).
Latency, it's all about latency
I have some rather memory-intensive code, that I did once run (or rather walk) on a ScaleMP machine (8 boards with 8 cores each (older incarnation)). Performance was dismal. Why? Each core thread may need access to each part of memory, because the outcome for each pixel in these huge images may depend on any pixel in the image, and you do not know beforehand which ones matter. Everything works hunky-dory as long as each processor only accesses the memory on its board, but the moment it needs large amounts of data from another board, latency kills performance. Getting a speed-up of 0.5 at 2 threads (if they weren't explicitly pinned to cores on the same board) is rather discouraging.
What they are doing is putting a software layer over a distributed memory or NUMA machine, so as to hide the complexities and allow shared memory algorithms to run (or rather walk) without the need to rewrite the code. ScaleMP does hide the actual NUMA architecture very well. Curiously, this leads to problems when optimizing the parallel code for that particular hardware. Because details are too well hidden. You really need to understand the memory architecture and the latencies of the machine to design the appropriate algorithm. Parallel programming on shared-memory machines and distributed-memory/NUMA machines are two very different ball-games, often requiring a careful rethink of the algorithms, in order to get the processors spend their time working, not talking (just like an old-fashioned classroom), or waiting for data.
A ScaleMP-like approach could work if the latencies are kept very low (like the QPI approach). On run-of-the-mill network connections (or even Infiniband), you need to rethink shared memory code, not so much because of bandwidth, but because of latency. For Cell/GPU type systems similar rethinks are needed, for much the same reason
Or: OOOK! as the librarian warns you not to land on the dome of the library.
Heel, FIDO! Heel!
Sorry, couldn't resist.
But, But, But...
Was he wearing suitable sun-block protection on his bare arms?
We must know!!!!!
A statement with "Balmer" and "overly aggressive" only needs
"is" in between
More seriously, it looks like my decision to postpone the acquisition of a laptop until such time as MS backtracked was a good one
The coolant of choice is raspberry juice
I'll get me coat
I'll drink to that!
Who says all researchers live in an ivory tower?
Seen from the other side, Hotmail is a pain too
When people subscribe to a forum I help moderate, our software sends an authentication e-mail, with a link to let the user authenticate himself. Hotmail, and hotmail alone, corrupts the url we send, so an administrator has had to programme a workaround. Let's hope and pray that Outlook.com does mess up in the same way.
Standards? MS has heard of them, I recall.
I know, I am an eternal optimist.
Yep, noticed the same. Even the most measured posts are receiving thumbs down from somebody. Not necessarily an American though, there are plenty of idiots on either side of the big pond. Idiocy is very democratic in that sense
Re: Common Sense...
There is still a lot of common sense about, I see it all around me every day. I see morons too, of course, but they are in somewhat shorter supply. Modern communication technology just means you hear about the morons much quicker. Do not forget, people being sensible is not something that sells papers, or generates clicks on adds.
Silica <> glass
Silica or quartz is not (often) a true glass. Fused silica is used in optics, but due to the high temperatures needed for glass transition it is limited in its use. Typical glass combines silica (about 75%) with sodium and calcium oxides. So silica is the main constituent in many cases, but not the whole story. Most silica typically has a proper crystalline structure, and is not glass-like in many properties (e.g. thermal conductivity of glass is typically closer to that of certain liquids than that of crystalline silica or carborundum (alumina)).
It needn't be intentional, it could just be a cock-up
Sorry, couldn't resist. Sounds like it's time to go already
Not all parallel programs have the same demands
There are many tasks that run like the clappers under CUDA. These are all those tasks that are of a more-or-less SIMD nature, like large matrix multiplications, Fourier transforms, and any other method that has a predefined processing order, preferably with a lot of micro-parallelism in there. Subtasks also need to be fairly isolated, to minimize communication load. For those tasks Kepler and Tesla-like processors are great (we have a couple).
However, there are also tasks in which the processing order is data driven, and where each processor might need to access arbitrary parts of the (large) data set here. I am currently doing multi-scale analysis of 3.9 Gpixel images, and doing that on a Kepler or Tesla board is a nightmare. Our 64-core Opteron machine gets between 32-50 times speed-up, because this algorithm is best using coarse-grained parallelism. X86-64 machines are not going away soon, and GP-GPU-processing is not a panacea (great though it is).
Re: Mrs F....
I cannot say that the fact that one particular missus cannot understand a phone is the best measure for usability. My missus moans about her android phone endlessly (which my kids understand in the blink of an eye), but at the same time refuses to listen to any advice (like what different buttons/apps do, what gestures are available, etc). In quite a few cases I find that moaning is not about getting help or advice, it is purely about getting attention. If you truly solve the problem, you deny them the chance to moan about that again.
BTW, this is not a female thing: we have several excellent and technically very competent female PhD students here. It is much more of an anti-tech mindset that some people develop.
Sorry, end of rant, it has been that kind of morning. Beer, because I feel I am in need of that.
Re: That is so, so beautiful
To see the Horse-head nebula you need very dark sites, a big scope, and for preference an H-beta filter. Even with my 8" in the Alps I failed to spot it (did not have the filter though, next winter might be better).
We are lucky to live in a time when we have instruments like Hubble and Herschel to capture such beauty.
even at the subatomic level, being hit by a wimp does have much effect
Yeah, right. I should have gone home long ago
Can you install two dashboards using SLI?
Just to keep back-seat drivers occupied
Re: Maybe the queen just likes having all the hot-looking young ants to herself?
And the young'uns like to be near the queen of course. To paraphrase Loudon Wainwright III
"The cutest ant that I have ever seen
is our own big fat sexy queen!
True she hasn't got such great legs,
but you should see the girl lay eggs!"
Mine's the one with the dead skunk print on the back.
I patiently await
A virus scanner that identifies itself as malware
At least it will remove itself, or at least file harakiri.dll
Interesting concept. From the same company that produces the transformer stuff that seems like the most interesting tablet to fulfil my needs. Next up, a padphone transformer?
That is why they talk about the edge of the observable universe. One could also call this "edge" our event horizon. Just because crayons work in 2D does not mean 3-D (or for that matter n-D, for any positive integer n) objects cannot have an edge (or boundary if you like).
Biofuels do have a long history
T34 Tanks are said to have run on vodka or bootleg drink on occasion.
A waste of good drink, perhaps, but it may have prevented blindness.
(it cannot have been scumble, as that would have eaten its way through the metal of the engine)
Re: Locals bearing flaming torches and pitchforks
But, but, but,..... was one member of the team called Igor?
Please let somebody say "Yeth, Marthter!!"
"but the battery life will suck. Even with induction charging it will be a pain."
I have this mental image of an induction charger based on a cattle prod
It's withdrawal symptoms from too few BOFH episodes
Really time to go; hat, coat, outahere!
".... a computer on their wrist and a computer on their face?(smart specs)"
I thought face-installed computers were quite old technology, generally available whenever someone ticks off the the BOFH
OK, time to go
And I had almost got my special toner to get laser printed web-pages to blink where required perfected!
Of course there are hurdles, that is why research is needed (hence the phrase "if we knew what we were doing it would not be research" ;-) ). There are many ways this can go pear-shaped, but I applaud the aim, and the proposal is plausible enough to investigate further. It is an audacious and exciting proposal.
This scheme will need a rethink when going to the outer planets such as Jupiter, or its moon Europa, given the much lower intensity of solar radiation. Some other source of electric power will be needed.
Millennium hand and shrimp, I told em I told em, they'd only run out, buggrit, buggrem, doorsteps, I told em, I told em, don't try the blarney gobble on me, juggins, buggrit, buggrit, millennium hand and shrimp
Re: Are they serious?
So the full name of the ship is not USS Ponce da Quirm?
Mine is the one with "Eric" in the pocket
Re: Thinking Machines
Oh yes! We had a CM-5 in our computer centre. That was seriously cool. The Cray J-932 right next to it mainly had an ultra-cool power led (rectangular, 1 x 10 cm or so affair), but the CM-5 looked like it would fit in in the higher budget class of SF movie.
The Elan Enterprise brings back memories, I used to have an Enterprise 128 as a kid. These had a nifty expansion slot at the side which allowed all sorts of people (students too) to build their own extensions (I once saw a working (!!) home-brew 4MB hard drive attached to one). It was a lot easier to get on with than the CDC-6600 (aka Cyber 74) on which I did my first computer practicals.
Is there no nostalgia icon?
Re: Back in the days . . .
The BOFH had a field day having his boss shout all the forbidden words "to build up a database" of forbidden words for their newfangled speech recognition software, as I recall.
Re: Hate speech not the best indicator
Very true, I do not doubt. You often see people of different ethnicity living side by side harmoniously during good times. It is when the economy goes down the toilet that people like to point the finger of blame to anyone who looks different (god forbid I am to blame, after all). Sad but very human, I am afraid. Much the same happened in former Yugoslavia.
Re: Cue a random word generator.
Like swut, joojooflop, and turlingdrome?
So long as they don't start saying Belgium (whoops)
Re: Seriously Dave?
I somehow doubt you could do that unnoticed by any satellite. If anything elongated an of the right size is loaded onto a ship or barge, rest assured something up there will read the serial numbers (OK not quite perhaps, but close enough).
Re: It's whether the degree is *hard* or *soft*
If we want to be scientific about it, we should have a hardness measure for degrees. Before embarking into a formal definition of this hardness, we could at least devise an informal scale similar to Mohs scale in mineralogy: Hardness scale 10 might be a PhD in quantum physics or cosmology, whereas hardness 1 would be a bachelor in underwater basket weaving.
Furthermore, I propose that very hard degrees must come with a diploma or certificate that is hard enough to be used to whack potential employers around the head. The softest degrees should come with a fluffy pink certificate.
Note that hardness has no repercussion for usefulness in a particular trade or profession. A quantum physicist might be of limited use in a nursing home.
Re: It's not the same without Neil anyway
Is it me, or are managers (and politicians of course, always hard to keep vermin out) in charge at NASA, rather than engineers, kick-arse test pilots, and people with vision?
Pity, NASA gave me some of my fondest childhood memories.
Having said that, there are still some awesome projects they do carry off. You have to just love those Mars rovers, to name just one example (OK, three). They show there are still star engineers at NASA.
Re: Mixed lessons from history?
The story I heard was that the Russians bought one Nene engine (legally) and said, thank you very much, we will copy them, without bothering about licences, but I might well be wrong. Both stories are equally believable: A government cynically copying stuff developed elsewhere or an arms manufacturer cynically selling military gear to anybody with enough cash.
Re: Ever wondered if...
The nearest supernova remnant to you is you, but it goes a bit far to point to a distant (actually, close by on a cosmological scale) supernova in Messier 101 a year or two back and say (in a high pitched voice) MUMMY!!!, as I heard one amateur astronomer do at a star party.
Re: That's a lot of eels!
Stealthiest Monty Python link of the decade, methinks.
My nipples explode with delight!
Doessss thissss mean ....
I can marry my TVsessss, my preciousssss?
I'll get me coat
Re: Its an interesting idea...
A problem with bigger stars is that they burn up much more quickly. They also output much more UV. Besides, smaller stars are far more numerous, so it does not make much sense to go for the big ones
Re:"If we did leave the solar system, where should we go?"
And when they find a perfect planet, somebody is bound to say:
Yeah, but you know how it is with travel destinations: they look all shiny in the brochure, but when you get there the landing strip is awful, the customs officers rude, the taxi driver rips you of and drives you to your hotel which hasn't even been built yet, the sand on the beach scorching hot, but the sea is freezing cold for some reason, and it's polluted, and the Germans have taken all the towels and deckchairs, the food is awful and the toilets wont flush, the next-door kids will making far too much noise and the disco next door means you can't sleep a wink!
We might just as well stay at home or go to Southend-on-Sea
Such people should be sent of on a B-Ark to a small blue-green planet at the unfashionable end of the western spiral arm of the galaxy.
Oh, hang on.....
Alternatively you could name your servers
Ankh, Morpork, Quirm, Pseudopolis, Lancre, Genua, Sto Lat, ..........
Here they used Pallas, Zeus, and Poseidon. I got some blank stares from the CIT crowd (Philistines, the lot of them ;-) ) when I suggested Offler, Om, and Nuggan
I'll get me coat!
"The only similarity is that both rings are round!"
As J.R.R. Tolkien said when a (Swedish, I think) translator drew lengthy comparison with Wagner's "Ring des Nibelungen." I think the museum is hoping to ride on the popularity of the film to draw in visitors (can't blame them).
Magic rings abound in myths and legends, and Tolkien new many (Kalevala, Mabinogion, Edda, etc.), and inspiration has many sources. Also, in the Hobbit, the ring is simply a handy tool, and only in the LotR does it become sinister.
Re: Interesting simulation
I have seen spiral arms develop in simulations of collisions of galaxies run by a colleague at the astronomy department, where they appear to be material structures. I must have a look at the paper later.
When I did astronomy at the Kapteyn Institute (in the 1980s), a similar theory floated about, which suggested the spiral arms are essentially a compression wave running through the gas and dust, triggering star formation in spiral patterns, and the hot, short-lived stars lit up the surrounding gas with their UV radiation. Shortly after the wave passed, the bright stars burnt up, and the amount of light decreased, without the total mass density changing much. The theory behind this simulation runs along a similar pattern, although in the 1980s simulating anything this big was impossible, of course.
Re: "Almost-planet Vesta"
New keyboard please
- Comment Renewable energy 'simply WON'T WORK': Top Google engineers
- Useless 'computer engineer' Barbie FIRED in three-way fsck row
- Game Theory Dragon Age Inquisition: Our chief weapons are...
- 'How a censorious and moralistic blogger ruined my evening'
- Amazon warming up 'cheapo web video' cannon to SINK Netflix