Domain: rochester.edu
Stories and comments across the archive that link to rochester.edu.
Comments · 323
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Re:kernel patches?From "The Google File System" (pdf)", pag 14:
"When appropriate, we improve the kernel and share the changes with open source community"
A "grep -R google *" In my 2.6.5 kernel tree returns back:
drivers/net/arcfour.c: * by Frank Cusack
drivers/net/ppp_mppe_compress.c: * By Frank Cusack
As established in the links he works in Network Working Group of Google -
Re:Nanotech misconceptions
There are possible risks with nanotechnology, especially since we don't have a full grasp of what the newly engineered particles can do.
Gunter Oberdorster at University of Rochester http://www2.envmed.rochester.edu/envmed/tox/facul
t y/oberdoerster.html found that fullerenes caused "damage" to the brains of fish. Now a researcher from Rice recently gave a lecture here at the U of South Carolina and called some of that research into question, but still you have to wonder. Also, there is the problem of metals from nanopackaging surrounding chemo delivery particles http://www.gatech.edu/news-room/release.php?id=450 possibly collecting in the pancreas. Also research on some particles have suggested that they might cross the blood-brain barrier in humans. While this might be good for dealing with brain tumors http://www.nano.org.uk/thisweek78.htm it also raises the very real possibility that something we don't want in the brain might get there.While I'm not all about regulating the nano-industry into oblivion, I would rather we treat it with much respect. I know that there is an "Asilomar" style conference on nano in the planning for either late this year or early next year partially sponsored by U of South Carolina http://www.nano.sc.edu/
Let's not assume anything is safe, after all, look what happened when nuclear power was tumpeted as the salvation discovery.
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Re:This is an age old argument for MMORPG....
You're mixing up economics models. Price in a monopoly is what the market will bear ( == high). Price in a free market is marginal cost ( == low). Here is a brief summary.
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bad storyIt's rather a poorly-written article with a lot of 1950's science fiction predictions about the future. The field of fuzzy algorithms has existed for ages. Fuzzy algorithms don't rely on random results. Rather, they use the "p-bits" to perform their calculations. P-bits are not the same as random bits. On the contrary, p-bits are "don't care" or "flexible" values that take into account multiple possibilities at the same time.
Random results are terrible because they are random. The scientific method depends upon experiments that can be repeated by other researchers. You can't base a theory on results that don't correlate with the inputs. You can repeat the experiment to obtain a probablistic model but not certainty.
A computer chip that yields unpredictable results is not going to magically recognize the image of a chair, much less a face because a chip that can't execute a program is more akin to the movie Short Circuit where the appliances go whacky. To me the author confuses the concept of fuzzy algorithms with random trials.
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Re:Beowulf & Grendel: The Musical!The scary part is such things exist:
Pickering, Ken, and Keith Cole. Beowulf, A Rock Musical. Schulenburg, TX: I. E. Clark, 1986.
The lyrics go, I kid you not, something like "Beo- Beo- Beo- Beo- Beowulf!"
This item is the libretto for a British musical from the early 1980s. Beowulf, A Rock Musical is meant for school-aged children, and is notable for its depiction of Grendel as a black-hearted, leather-clad punk rocker with a cockney accent--a clear reaction against the punk's place as an anti-establishment icon in Margaret Thatcher-era Britain.
Found via Beowulfiana -
danger
I think there is a very real danger of this only being contributed to by hardcore proponents of P2P and the danger in that is that no one will subjectively evaluate alternatives. The academic research seems to suggest that P2P isn't necessarily the best alternative and that something more centralized like Napster or really centralized like a client-server model but where anyone can upload/download is better in terms of overall cost...at least for legal stuff.
For this to be useful both sides must be presented well and P2P still win...if that doesn't happen then it's not worth much of anything. -
Liquid Nitrogen and Pumpkin Chunkin...I'm a grad student now, but I've taught a lot of non-sciency undergrads, and it's mostly important to have things they can do that are hands-on and visually interesting.
[A side note: the most important thing to remember is that for this to be successful, you must make the students feel comfortable. I know many students who were turned off to science, and it was always by a bad experience in high school. Students will be interested in science, but it must be understandable to them.
High technology is fun, but the average student doesn't know the first thing about programming or building a robot, and might not find something interesting if they don't understand it. So your project should be aimed at things that build interest, but are also easy for high school students to understand. Take care to emphasize that anyone can do it if they're willing to work at it a little. Students must not be allowed to feel dumb or stupid, or to think that the teacher feels they are.]
If you want something like a fair or competition, you might try a pumpkin' chunkin' competition. I don't mean large scale, though. You could have fun with a smaller competition such as the one at my university. The launchers must fit in a 4-foot cube and must be human powered. These limitations make it fairly safe, and the competition is an entertaining and respected event. In the process, students can learn some basic things about ballistics and engineering.
Alternately, you could form a project to build a larger single device, like a trebuchet or catapult. This can be a lot of fun to fire (for a rally before a big game, perhaps?) and provide a larger project where students can use a variety of skills including math, physics, and metal- or wood-working.
On the other hand, if you want smaller projects that might fit into a short class, here are a few suggestions:
- Anything with liquid nitrogen is cool by definition.
:-) You can make liquid nitrogen ice cream, freeze a rubber ball and shatter it, let the nitrogen roll off the back of your hand... all the standard tricks. In addition you could get one of the small superconductor kits and levitate a small magnet; you can talk about new materials research.- Bring in a strobe light and look at things under it like water from a faucet, a turning bicycle wheel, or other semi-periodic phenomena.
- Astronomy, with a good telescope, can be really fun. Start off with something easy like looking at the surface of the moon, and save calculating orbits for much later.
;-)- Photography appeals to non-technical students but also introduces a lot of more technical subjects in a non-threatening way.
There are all kinds of great activities that will catch the interest of students. I don't think the kind of activity is as important as its level.
Ask yourself: will the average high school student see your activity advertised and think "I wish I could do that," or "I know I could do that!" ? Use that as your guide.
Good luck!
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Liquid Nitrogen and Pumpkin Chunkin...I'm a grad student now, but I've taught a lot of non-sciency undergrads, and it's mostly important to have things they can do that are hands-on and visually interesting.
[A side note: the most important thing to remember is that for this to be successful, you must make the students feel comfortable. I know many students who were turned off to science, and it was always by a bad experience in high school. Students will be interested in science, but it must be understandable to them.
High technology is fun, but the average student doesn't know the first thing about programming or building a robot, and might not find something interesting if they don't understand it. So your project should be aimed at things that build interest, but are also easy for high school students to understand. Take care to emphasize that anyone can do it if they're willing to work at it a little. Students must not be allowed to feel dumb or stupid, or to think that the teacher feels they are.]
If you want something like a fair or competition, you might try a pumpkin' chunkin' competition. I don't mean large scale, though. You could have fun with a smaller competition such as the one at my university. The launchers must fit in a 4-foot cube and must be human powered. These limitations make it fairly safe, and the competition is an entertaining and respected event. In the process, students can learn some basic things about ballistics and engineering.
Alternately, you could form a project to build a larger single device, like a trebuchet or catapult. This can be a lot of fun to fire (for a rally before a big game, perhaps?) and provide a larger project where students can use a variety of skills including math, physics, and metal- or wood-working.
On the other hand, if you want smaller projects that might fit into a short class, here are a few suggestions:
- Anything with liquid nitrogen is cool by definition.
:-) You can make liquid nitrogen ice cream, freeze a rubber ball and shatter it, let the nitrogen roll off the back of your hand... all the standard tricks. In addition you could get one of the small superconductor kits and levitate a small magnet; you can talk about new materials research.- Bring in a strobe light and look at things under it like water from a faucet, a turning bicycle wheel, or other semi-periodic phenomena.
- Astronomy, with a good telescope, can be really fun. Start off with something easy like looking at the surface of the moon, and save calculating orbits for much later.
;-)- Photography appeals to non-technical students but also introduces a lot of more technical subjects in a non-threatening way.
There are all kinds of great activities that will catch the interest of students. I don't think the kind of activity is as important as its level.
Ask yourself: will the average high school student see your activity advertised and think "I wish I could do that," or "I know I could do that!" ? Use that as your guide.
Good luck!
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Re:The Law of Thermodynamics
Is your username a cold fusion pun?
BTW, I work on the opposite side of the pond as a technician on the 'other' fusion here: http://www.lle.rochester.edu/. Friendly competition and all that. cheers! -
Google File System
Implementation details of the Google File System can be found in this paper by Google engineers.
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Re:Some Trivia about 'Clarke Point'
IDL may be the language you are referring to. IDL is indeed based on FORTRAN, and is pretty good at efficiant matrix calculations. While expensive, it is still in use in the astronomical circles, due to the efficiancy with which it can manipulate CCD images.
While an undregraduate at Alfred University, I used IDL quite a bit in my upper level astronomy classes. A friend of mine is part of the University of Rochester Near Infrared Astronomy Group, where his main task is to code monstrosities in IDL to deal with all their astronomical data. -
Re:Strawberry Shortcake and American Greetings
You will never see the comic from them officially, they cannot display it for fear of lawsuits. Fortunately some kind souls saved the picture the day it was originally posted. You can see the comic here
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High quality large format artwork?Where can I buy a high quality poster of
http://mail.rochester.edu/~dr002j/pics/contraband
_ comic.jpg Strawberry Shortcake?Perhaps the best artwork ever on PA, and the best supressed non-porn artwork anywhere.
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Proper attribution!
Is there a reason that
/. OP's show a disgraceful tendency to claim authorship of text they didn't write? Neutron_p most definitely didn't *write* that text - he or she copied and pasted it from physorg.com, making some minor cosmetic adjustments to the text. And that text came verbatim from a press release from the University of Rochester.
Is it really that difficult to say "PhysOrg.com reports" at the start of the post?
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Bah ...
I'm much more impressed with Dr. Benjamin Franklin's invention of the jet ski.
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Re:Weapons research
Jim you're on my slashdot friends list but I'm afraid I must completely disagree with you here.
:o)
Tokamaks have problems, yes, but I don't think it's known weather these problems will prohibit their utilization as a fusion power source. For instance if a plasma instability forms in a tokamak while running (happens all the time) and the plasma bumps the divertor or the inside of the chamber it most certainly will not be bomb like and won't "result in burn-through" either. The introduction of (relatively) high Z material (carbon from graphite, iron, or aluminum from chamber walls) will result in INSTANT plasma quenching via the plasma radiating a huge portion of its energy through bremsstrahlung. This causes burn marks and other dust problems in the chamber but can't cause burn through of the thick metal vacuum chamber walls. And if there is a catastrophic breach of the plasma vessel it definitely, DEFINITELY will never be anything even close to a "chernobyl-style quarantine". At most, a couple grams of radioactive tritium (3-hydrogen) are contained in the vessel while "burning", even considering a total failure of containment and burnoff (a small explosion, to be sure) of all the hydrogen to form tritiated water (forming molecules of TOH or TOT rather than HOH) the amount of radioisotope release will be in the tens of KiloCurie range. Tritium is the least dangerous radioactive isotope that exists (I work with it daily), with a ~12 year half life and an average beta particle emission energy in the 5KeV range to a max of 18KeV, barely enough to go a few mm in air before being blocked; and owing to the fact that both hydrogen and water are volatile, it will be VERY quickly be evenly dispersed and diluted in the atmosphere and oceans. I doubt anyone working in the plant would die if assuming sufficient containment were used.
Tokamaks do have the issue of neutron activation to worry about among other things but I think these are at least workable problems. Remember, Tokamaks have held the world record for plasma temperatures and containment times for a very long time.
But ultimately you may be right, the Tokamak may prove unworkable from an economic energy generation standpoint. I think the project at MIT using a levatated dipole for more "natural" quiescent plasma containment looks very interesting (promising? maybe), for instance.
All of this said, BIG congratulations to the Sandia Z-machine people!! They deserve it. The energies and powers (~300 Twatts!) they've achieved are barely a factor away from those expected on the finished National Ignition Facility. The lab where I work supplied the parts for the laser called the Z-Beamlet they use to "backlight" targets so they can be viewed in X-rays as they're being imploded on Z. Looks like they've put it to good use. As new technologies like these (and others achieving PETAwatt powers) come online they will open completely new doors to fusion research This is an exciting time for very high energy experimental plasma physics. -
Re:Weapons research
Jim you're on my slashdot friends list but I'm afraid I must completely disagree with you here.
:o)
Tokamaks have problems, yes, but I don't think it's known weather these problems will prohibit their utilization as a fusion power source. For instance if a plasma instability forms in a tokamak while running (happens all the time) and the plasma bumps the divertor or the inside of the chamber it most certainly will not be bomb like and won't "result in burn-through" either. The introduction of (relatively) high Z material (carbon from graphite, iron, or aluminum from chamber walls) will result in INSTANT plasma quenching via the plasma radiating a huge portion of its energy through bremsstrahlung. This causes burn marks and other dust problems in the chamber but can't cause burn through of the thick metal vacuum chamber walls. And if there is a catastrophic breach of the plasma vessel it definitely, DEFINITELY will never be anything even close to a "chernobyl-style quarantine". At most, a couple grams of radioactive tritium (3-hydrogen) are contained in the vessel while "burning", even considering a total failure of containment and burnoff (a small explosion, to be sure) of all the hydrogen to form tritiated water (forming molecules of TOH or TOT rather than HOH) the amount of radioisotope release will be in the tens of KiloCurie range. Tritium is the least dangerous radioactive isotope that exists (I work with it daily), with a ~12 year half life and an average beta particle emission energy in the 5KeV range to a max of 18KeV, barely enough to go a few mm in air before being blocked; and owing to the fact that both hydrogen and water are volatile, it will be VERY quickly be evenly dispersed and diluted in the atmosphere and oceans. I doubt anyone working in the plant would die if assuming sufficient containment were used.
Tokamaks do have the issue of neutron activation to worry about among other things but I think these are at least workable problems. Remember, Tokamaks have held the world record for plasma temperatures and containment times for a very long time.
But ultimately you may be right, the Tokamak may prove unworkable from an economic energy generation standpoint. I think the project at MIT using a levatated dipole for more "natural" quiescent plasma containment looks very interesting (promising? maybe), for instance.
All of this said, BIG congratulations to the Sandia Z-machine people!! They deserve it. The energies and powers (~300 Twatts!) they've achieved are barely a factor away from those expected on the finished National Ignition Facility. The lab where I work supplied the parts for the laser called the Z-Beamlet they use to "backlight" targets so they can be viewed in X-rays as they're being imploded on Z. Looks like they've put it to good use. As new technologies like these (and others achieving PETAwatt powers) come online they will open completely new doors to fusion research This is an exciting time for very high energy experimental plasma physics. -
Re:Don't take this as a troll, but..
Its well known that
- Google has from 50,000 - 100,000 servers
- they run linux on "barebones" machines (1u cases with no sides/top) to cut costs
- This paper by Google engineers documents how Google's distributed, fault tolerant system works. -
Re:My point is,
As for the rest, you're totally out of your gourd. How is assault with toxic chemicals not still assault? How is a misleading contract and a defective product not fraud?
If you can't figure out the answers yourself, you're hazardously naive.
Read some USA history. Assault and fraud have been illegal for hundreds of years, yet in the 20th century pollution and defective products were legal until specific new laws were created to combat it.
Something that's not forceful and not fraudulent can still be not fair.
About the only times they can get away with xeing complete schmucks and alienating their own customers are when they have government-granted protection from the consequences
Again, you show an astounding historical ignorance, well below even the maligned standards of USA public schooling.
Monopolies WILL happen, even without government aid. But the Libertarian Party, by principle, can never act against a monopolist. That means governance will be ceded to the next company which emerges as a natural monopoly.
(There's nothing wrong with supporting the LP if it's with the understanding that their views will never achieve near dominance, and you only want to encourage a push in that direction)
government-granted monopoly
That's more ignorance, although of a more excusable variety, because fewer people are really aware of what "government" is. "Government" is that which "governs". If that entity which you today label "government" abdicates many of its functions, they will be taken up by other, commercial operations- meaning corporations become the new government. -
One word
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Re:Petawatt power lasers ...
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Re:Petawatt power lasers ...
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Yeah I'm sure they're awesome...
...when they show up on time...
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Re:ARE YOU NUTS?!
I don't get it... Would it make a chain reaction???
No. It would make a perfectly normal, everyday exothermic chemical reaction.
Cesium FAQ
Shoudn't it be illegal to wear???!!!
If atoms are outlawed only outlaws will have atoms.
KFG -
Re:Google FS
sorry, working link right here (PDF)
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Raw wood, eh?
Funny how unvarnished, unglued wood is wonderful and safe. Most people in the woodworking industry (especially the fine work stuff, heavy hardwoods, etc.) feel somewhat differently. Check out this table of wood toxicities for some properly backed data.
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Re:Step by Step walkthoughIt'd be really cool if the manual went into the more interesting Google features:
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Re:Another solution in search of problem
Which makes me wonder: Is google's next killer app a new filesystem?
Google already created their own filesystem with substantial architectural similarites to the AFS distributed filesystem. -
Re:Well..
- I think its a classic example of building your business around your strength - the searching capability.
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mirror
Here's a mirror of the 3.84MB video.
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Java WFM in Firefox
Which virtual machine are you trying to install? I just browsed to this simple Java applet example and it worked out-of-the-box. Note that I installed Java2 SDK 1.4.something a long time ago, before installing Firefox 0.9 (from scratch) using the Windows installer. In fact, I installed all my plug-ins before using Firefox 0.9. What are you referring to? Is it possible that your unfortunate situation is just a special case or an anomaly?
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Dear Slash from Guns 'N RosesDear Slash from Guns 'N Roses,
Here is the Google File System (GFS) paper from SOSP '03 that you requested.
-Letter
P.S. Blame Axl for letting RedHat steal the GFS acronym for their Global File System!
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Excellent!
Although Google obviously won't be releasing it's search algorithms it might well release the code for things like the Google FileSystem (PDF) which may benefit a lot of people.
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Re:Problems
From a google on "Element Distribution in the Earth", I got many sites, one of which has this graph. It seems the consensus among those sites that the crust is 46% oxygen which is not a suprise to a geologist since most crustal rocks are silicates. The mass of the entire Earth is about 30% (oops, I was too high). Still oxygen makes up an impressive fraction of the mass of the Earth.
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Re:right...
I guess companies tend to become a little greedy and overzealous given a chance.....
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Re:Future of armed infantry
Hmm... looking into the subject more, I ran into a paper that discusses a number of different phenomina, including the use of Raman scattering to shift the center frequency of an incoherent light field, even keeping the spectral power distribution. I hadn't taken the time to read about Raman scattering before... interesting. You could even use it to amplify your low frequency components, since any components with short wavelengths will act as the pump frequency and will lose power. It also keeps the directional component, contrasting with Brillouin scattering which inverts it. I'm not sure how far down you could shift the frequency with Raman scattering, though, as I haven't found any formulae on the subject...
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Re:You almost got me there ..
From http://teacher.nsrl.rochester.edu/phy_labs/Append
i xE/AppendixE.html the definition of the Scientific Method is:- Observation and description of a phenomenon or group of phenomena.
- Formulation of an hypothesis to explain the phenomena. In physics, the hypothesis often takes the form of a causal mechanism or a mathematical relation.
- Use of the hypothesis to predict the existence of other phenomena, or to predict quantitatively the results of new observations.
- Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments.
Archaeology can do #1, and #2. Arguably it can do #3. However, #4 is right out as you don't have the ability to create alternate realities.
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Re:Problems with decipherment
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Re:Remember Lady Ada
Actually, while Ada Lovelace saw the potential of Babbage's Analytical Engine, her inspiration for this was Joseph Jacquard's punch-card-progammable Jacquard loom. Jacquards invention was also later copied as Hollerith's computer punched cards.
The distinctive characteristic of the Analytical Engine, and that which has rendered it possible to endow mechanism with such extensive faculties as bid fair to make this engine the executive right-hand of abstract algebra, is the introduction into it of the principle which Jacquard devised for regulating, by means of punched cards, the most complicated patterns in the fabrication of brocaded stuffs. It is in this that the distinction between the two engines lies. Nothing of the sort exists in the Difference Engine. We may say most aptly that the Analytical Engine weaves algebraical patterns just as the Jacquard-loom weaves flowers and leaves.
Lovelace on Jacquard
Jacquard loom
Jacquard loom output
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Re:$278k ??
Google Filesystem replicates same data on three nodes (by default, can be configured to more), so the probability of data loss is rather small. Source here.
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Re:Congest it
Here's the I2 picture from when the RIT DC hub was shut down about a year ago. Notice the growth in the bottom long-term graph. That hub was open to everyone, if I remember correctly. MRTG stats
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Public paper on Google File SystemHere is a PDF file of the paper.
If that link gets slashdotted, here is another link of a PDF PowerPoint presenation.
Good read! This paper (with the discusion of the goodness/fastness of file appends) made me more interested in Prevalence - so much so that I am using it for my new project.
-Mark
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Re:How Google do that?
There is also a paper that describes their storage infrastructure (Google File System) here
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Re:Look at Google
Google never writes to the filesystem -- it's all in memory and temporary. They only use the disk to boot the system.
For their production service, I understand that they keep it all in memory. But it's hardly temporary.
Hardly anyone is like Google.
For now. Google was one of the first companies to take advantage of the fact that RAM and procesing power have become ridiculously cheap. SQL databases arose in an era when 32k was a fair bit of RAM, and where a business computer was one or more refrigerator-sized units kept in a sacred temple.
Now computers are cheap and disposable. I can fill a rack with cheap 1Us and get processing power that Sun can't match at 10 times the price. The only trick is to write your apps in such a way that you can tolerate hardware failures. That's a little hard, but it paid off handsomely for Google. Others will learn this trick.
You can bet they'll be using RAID (etc) for the GMail service.
You'd lose that bet. They already have built their own distributed network filesystem, GFS, that holds at least hundreds of terabytes. It has performance and reliability levels well above any RAID installation I've ever heard of, and it uses cheap commodity hardware to do it. I'd bet that GMail will be built on top of a variant of GFS or some other in-house technology. -
saw this first hand
I run a college movie group that sometimes does sneak previews of upcoming films. I was blown away when I heard that for our most recent preview (Gothika, total crap btw) they wanted to bring in night vision goggles. They wound up basically frisking everyone that came in too, and even turned away kids with cameras in their cell phones. The people who got in didn't actually seem to mind the search that much, they kind of understood. Nonetheless, it was the first time we had a major external security force at one of our screenings.
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How google works not so secret
"..of this legal action might be that some of the secrets of how Google works will be revealed?"
What secrets? Here's a 15-page technical paper on the Google File System for starters (just the first thing that turns up in a google search for google file system). Most everything else you might want to know of these 'secrets' is out there somewhere. -
Re:Symphonies are self-conducted anyway
Dear god, I hate posting to slashdot, but..... I play second bassoon professionally for this orchestra, and have played in many ensembles from my college days here including the Aspen Festival and Concert orchestras and the Moscow Chamber Orchestra. There is not a single professional musician I have met in my 15 years of playing that shares your opinion. Conductors are about rehearsals, not performances.
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Google don't use RAID...
...but rather (all this according to the article) their own distributed, fault-tolerant Google Filesystem (GFS) [PDF]. Apparently each of their 1/2 depth 1U servers has only one or two drives. If a server fails (which happens routinely with 100k servers) then it's simply left in place and the data is automatically replicated onto another server from one of the redundant copies.
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P2P Research
There are several P2P research projects that are looking at building reliabale and scalable P2P systems.
Take a look at Tapestry, and Chord (and read some of the papers) to understand the issues involved in providing scalable and high performance P2P services. Not only is scalable search and overlay graph connectivity an issue, but also node failure and short session times of P2P nodes.
Additionally, when you actually handle the issue of downloading data, building application-lvel multicast trees to distribute the data efficiently on a large scale is not easy. Two papers from SOSP '03 SplitStream, and Bullet address that issue. -
Re:Well there is a real difference
It's a known fact that Google doesn't manage its files in the same way as everyone else. They don't even use the same filesystem as everyone else. They use GFS, the Google Filesystem instead.
If they were to use GFS in just the right way and/or extend it to increase reliability (with off-site redundancy, which they apparently do not have now), they could probably provide that storage pretty cheaply and pretty easily.