Understanding Moore's Law 179
S. Blocher writes "Ars Technica has a great article up, 'Understanding Moore's Law', that I think most geeks should read. The misrepresentation of Moore's Law in the media has always been a real pet peeve of mine, and this article does a great job of looking at the flipside of the 'bigger and faster' thesis to show how the Law isn't really just about doubling computer power."
Moore's ??? (Score:5, Insightful)
Re:Moore's ??? (Score:1, Redundant)
How about Moore's Prophecy?
Kind of catchy in this day and age.
Re:Moore's ??? (Score:1)
signed,
Max Power
--sex [slashdot.org]
Re:Moore's ??? (Score:2)
Oh, and is it me, or does that article jump around way too much? A bit to read when it does that...
Re:Moore's ??? (Score:4, Funny)
Re:Moore's ??? (Score:2)
Re:Moore's ??? (Score:2, Insightful)
Re:Moore's ??? (Score:4, Interesting)
Moore's Theorum?
Moore's Speculation? - this would have been good early on...
Moore's Principle?
Moore's Equation? - something for the big math fans to complain about...
Moore's Paradigm? - something for the cliche in all of us...
Moore's Model?
Moore's Formula?
I kind of like Moore's Determinant, but it's not very accurate.
But if we wander around changing things because we think they aren't right, that makes us revisionists. And revisionists are doomed to experience history for what they are sure is the first time.
Re:Moore's ??? (Score:3, Insightful)
It isn't a theorem, again because it was based on observation. It isn't provable.
So either observation or theory would have been appropriate.
We like our little "Laws" though ( such as Murphy's), so, like it or not, law it is, and law it shall remain.
Law's are so comforting to the masses, don'cha know. They eliminate all the messy conditional shit real life is made up of.
KFG
Re:Moore's ??? (Score:1)
Re:Moore's ??? (Score:4, Interesting)
Is it testable?
Is his research repeatable?
What studies have been published to support the hypothesis?
What was tested, and how? What controls were used?
Moore was making an economic projection in order to formulate a business plan. He was not establishing a new field of theoretical physics.
If we had to, and if we could discount the variables of economic incentive and R&D time, we could try to directly approach the theoretical limitations. Maybe find something other than silicon and transistors that will work better than the semiconductors we use today. (We only have made incremental improvements on the same basic structures).
The true appeal of "Moore's Law" is that we have become accustomed to seeing doublings of power in our computing devices. So much so, that any consumer product that doesn't promise twice the speed/capacity of what came before it, won't be all that exciting to us.
There are plenty of industries where a fraction of a percent increase in production will make you a hero, even in electronics engineering.
Re:Moore's ??? (Score:1)
Moore's Extrapolation?
Re:Moore's ??? (Score:2)
Re:Moore's ??? (Score:5, Interesting)
No scientist with half a head on his shoulders really thinks of laws as "laws" any more. They're observations of behaviour reduced to a mathmatical form for the purposes of understanding and prediction.
That is why it's Eintstein's *Theory* of Special Relativity, even though it is an even more accurate rendering of Newton's "Law." We gave up laws a century or so ago.
While at times language changes distressingly fast there are times when it seems impossible to change at all.
This is one of those times.
I'm afraid the resulting confussion, allowing President's to say dumb shit like "It's only a theory," may well never subside.
KFG
Re:Moore's ??? (Score:4, Interesting)
I beg to disagree.
Newton's laws are simple, definitive, and we're unlike to find anything that contradicts them--relativity deals with the shape of space, not how objects react to motion, and quantum mechanics, as far as they effect "objects", are just another force.
Classic Physics are undisputable--they can be observed by anyone with about thirty minutes of free time (or less). Relativity, on the other hand, has a rather smaller set of supporting data, and thus calling it a "law" isn't quite accurate just yet.
While at times language changes distressingly fast there are times when it seems impossible to change at all.
Most scientific laws are hundreds of years old--they've withstood the test of time. Relativity and other modern theories haven't withstood the test of time yet, but in a few centuries we'll be talking about "Einstein's Laws."
I'm afraid the resulting confussion, allowing President's to say dumb shit like "It's only a theory,"
You mean evolution, I assume.
The principle that living creatures evolve is observable, uncontestable, and hundreds of years old. High School students can test it with rabbits. Current evolution should be taught as and called "The Law of Evolution."
Now, when biologists start speculating about the fossil record, species relations, and where life came from, they're on territory that they can never prove to have a definite answer, and thus they should either use the same terminology that historians, not labcoat scientists use, or they should stick with "theory."
Re:Moore's ??? (Score:5, Informative)
Classical Physics is undisputed within a certain range of energies/time difference, but you cannot explain light causing a measurable pressure with newtons laws nor can you explain doppler shifts exactly.
Re:Moore's ??? (Score:2)
Depends on how many lobbyists you hire and politicians you bribe. :-)
Re:Moore's ??? (Score:2, Insightful)
Newton's Law is nothing more than special case of Einstein's Theory.
You may assume anything you wish, but I was refering to Relativity, not Evolution.
The Theory of evolution should not be taught as a law for the same reason Relativity should not be taught as a law.
There are *no* laws. Only observation and theory.
KFG
Re:Moore's ??? (Score:2)
Re:Moore's ??? (Score:4, Informative)
Yup, we're unlikely to find anything that contradicts them. Like, you know, a century's worth of experimental physics. But ignoring the pesky 20th century, no, you're not going to find anything to contradict them.
Newton's 'Laws' are simply convenient approximations. They tend to work quite reasonably in most circumstances, but they most certainly are not laws. A law is something that will always be true, everywhere; Newton's 'laws' break down as soon as you try to do anything unusual.
They're called laws because of historical prescedent (back in the day people played fast and loose with their terminology), but it's really quite disingenious.
And again, while neo-Darwinian Evolution is an incredibly good and compelling theory, it's going to remain just a theory until someone invents a time machine. While experiments can be performed to demonstrate small phylogenic changes, evolution discusses tremendous change over tremendous time-scales, and while it seems quite reasonable to believe that you can simply generalise observations about butterflies and rabbits out to millions of years (:-)), you can't exactly proove it, which is the point.
Calling something a law when it really isn't does a disservice to science; you're throwing the baby out with the bathwater. One of the most important things students can learn about science is that regardless of how strong or weak the evidence is for one theory, there's always the possibility for an alternate explanation, and to be able to judge the relative merits of the theories based on their supporting evidence and their implications.
Re:Moore's ??? (Score:2, Informative)
"Newton's laws are simple, definitive, and we're unlike to find anything that contradicts them.
"Yup, we're unlikely to find anything that contradicts them. Like, you know, a century's worth of experimental physics. But ignoring the pesky 20th century, no, you're not going to find anything to contradict them."
Except, of course, that you're wrong. Planesdragon was correct when he said that nothing had contradicted Newton's laws. The people who claim otherwise simply don't understand Newton's Laws.
(1) A body remains at rest or travels with constant velocity unless acted upon by an outside force.
True. Nothing in either quantum or relativistic physics contradict this. They do expand upon the what a force actually is, but they in no way contradict it.
(2) The force acting on a body is equal to its rate of change of momentum.
Trivially true. This isn't really a law, so much as a definition - in fact, the definition of a force. As a definition it can't disproven.
(3) Every action has an equal but opposite reaction.
True. Much like the first law, the implications of this are complicated by quantum and relativistic effects, but the law itself remains unchanged.
So, having stood for centuries, they certainly look like they deserve being called laws to me.
The meaning of "Theory" (Score:2)
I'll stick with "Theory," on the grounds that one meaning is "a systematic statement of principles involved." That is broader than "Law," and better describes the standings of both evolution and relativity.
As for the "it's only a theory" people, I doubt that calling evolution a "law" will change their minds.
Re:Moore's ??? (Score:2)
My most memorable day at physics class at Ohio State University was when my (nobel prize nominated) professor converted Einstien's theory into a Taylor series expansion equation, dropped off part of it (which translates into a loss of precision), and converted that into Newton's equations. You obviously don't understand relativity since you are getting special and general relativity confused. Newton was wrong. If you zoom in on a parabola enough it looks like a straight line. That's kind of what Newton did in comparison to Einstien. That is not to say there isn't something more accurate special relativity, but we don't know it yet and probably won't have tools to measure it. We do actually use special relativity. If it weren't for that our GPS system would not be nearly as accurate. This is why I moderated you as a troll. You stated a falsehood as if you were certain. Though it seems you believed what you said, there is no moderation option for "Wrong".
Re:Moore's ??? (Score:2)
Well, there's 'wrong' and there's 'wrong' it's a sliding scale. While it's true that he was 'wrong' in the narrow sense of the word, he got most of it right. Certainly much more so than other's before him. Almost all everyday phenomena can be readily explained by his 'laws'.
Einstein didn't so much prove Newton wrong, as proving him incomplete. Which is a different kind of 'wrong' than invalidating the whole theory/law, and instead state the oposite (c.f phlogistone).
Assimov wrote a nice essay on the subject: The Relativity of Wrong [answersinscience.org] which puts this more eloquently than I have.
Re:Moore's ??? (Score:2)
Re:Moore's ??? (Score:1)
I guess "you are under arrest for breaking Murphy's Law" would be kinda useful phrase, come to think of it.
Re:Moore's ??? (Score:2)
Fermat's Last Theorem isn't a theorem and Newton's Laws aren't universal laws (they break under certain conditions). Misnomers occur all the time, but yeah it is an annoying buzz-term.
Re:Moore's ??? (Score:5, Informative)
Re:Moore's ??? (Score:2)
Moore's Paradox... (Score:1, Offtopic)
A is and I don't believe A.
Such as: It's raining and I don't believe it.
The paradox lies in questioning the belief in a fact you've already attested to in the same statement.
-R
Re:Moore's ??? - Why Moore and not Turning? (Score:1)
Why does Moore get credit for this "law" and the "Moore machine"?
A.M. Turning in Mind, October 1950 p433-460 discussed both his predictions on the growth of computers (p442) and had diagrams and equations for what is now called in computer engineering a "Moore machine" (p440).
I will agree with anyone who says that Moore refined Turning's ideas. The way Turning predicted growth is hard to use as any sort of "law." However, the state diagram in Turning's article is pretty clear. I would call it a Turning machine rather than a Moore machine if I had my say.
Maybe someone here can finally provide me with a reason why Moore gets all the credit for Turning's ideas.
To me it seems clear that Moore had read Turning's article 15 years prior and used it as a basis for his ideas. Should Turning be given some credit?
Re:Moore's ??? - Why Moore and not Turning? (Score:2)
Moore was talking specifically about the number of devices per square inch on a single substrate. In other words, he was talking about integrated circuit semiconductor fabrication technology and the economics involved. Turing was dealing in much broader concepts.
Re:Moore's ??? (Score:1)
It seems like a good start would be to stop calling it a "law," a term that has some kind of meaning, in a scientific sense.
Oh, jeez. No one ever actually thought it was like a law of nature. ('Cept you, I guess.)
Re:Moore's ??? (Score:3, Funny)
Moore's "Rule of Thumb" doesn't have quite the same ring...
Re:Moore's ??? (Score:2)
It seems like a good start would be to stop calling it a "law," a term that has some kind of meaning, in a scientific sense.
"Law" isn't a scientific term. Science deals with theories that try to describe the world. You seem to imply there are some "special" theories that get promoted to "Law", but that's hardly scientific. Some of these things get names, and the names sometimes include "Law". But that's just a name, it doesn't mean they're different from theories that get names with "Theory" in it.
For instance, the "Laws of Thermodynamics" are a theory. A great theory.
Anyway, of course Moore's thing is just never going to be true for a long period, it's not even a try to describe the physical world. It's not as if it's still going to be true a billion years after the last human died. I call it "Moore's short term observation".
Just curious... (Score:1)
Just curious, but has anyone ever even heard of this before? It's very interesting, but the article was written in 1965, and I don't think current geeks know a lot about this. I certainty didn't
Re:Just curious... (Score:1)
What the press, and a lot of other people, seem to do is apply it to things like hard drives. Hard drives do seem to follow a similar principle, but i'm not sure if it's on the same scale as Moore's law.
Re:Just curious... (Score:1)
Gordon Moore is one of the more visionary and less well known folks in modern geek-dom...
Re:Just curious... (Score:1, Insightful)
Re:Just curious... (Score:1)
In typical /. fashion (Score:5, Funny)
Roger Moore's Law is: you get more chicks when you are James Bond than when you're Roger Moore. That's it right?
Another typical response (Score:2)
I am Roger Moore, you insensitive clod!
The 'M' laws (Score:5, Funny)
Microsoft's law: what you get when you put Moore's law and Murphy's law together.
Re:The 'M' laws (Score:1)
The number of critical bugs doubles every 18 months?
Moores law in action? (Score:5, Funny)
For every news artical about Moore's Law, there will be a two fold reduction in the amount of Moore's Law that is explained. Which at some point it becomes impossible to comprehend the difference between Moore's Law and Artical Fodder about why you need a new computer.
Re:Moores law in action? (Score:2, Funny)
There's two types of salesmen in other audio stores...the Specialist, who knows more and more about less and less until finally, he knows EVERYTHING about nothing.
And the Generalist, who knows less and less about more and more until finally, he knows nothing about everything.
I laugh when I hear it still because it's so damn true sometimes.
Re:Moores law in action? (Score:2)
Oh wait, you said *explained*...
The law is simple (Score:1, Funny)
Re:The law is simple (Score:1)
KFG
Isn't this law more about profit? (Score:1)
Re:Isn't this law more about profit? (Score:2, Interesting)
Of course profit is it's own incentive; doesn't take a genius to realize that. What you miss in my question is this "law" based on the fact that instead of continually saturating the market with current product Moore seemed to set a goal for engineers to help that ol' profit incentive.
Re:Isn't this law more about profit? (Score:2)
That way we'd all own something like a HP Beowulf Complex (Pavilions are much too small) 4550, or IBM's latest NetVista HIVE [nasa.gov] 8000.
Of course, laptops would just suck.
Cowboy Neal's Corollary to the Moore's Law (Score:4, Funny)
Re:Cowboy Neal's Corollary to the Moore's Law (Score:2)
and articles doubles in
It's not a law (Score:5, Insightful)
6 a : a statement of an order or relation of phenomena that so far as is known is invariable under the given conditions b : a general relation proved or assumed to hold between mathematical or logical expressions
Moore's Law only holds true to a point. There comes a time when only so much can be fit on that piece of silicon. The term conjecture might also be applicable.
It's not even that (Score:3, Interesting)
6 a : a statement of an order or relation of phenomena that so far as is known is invariable under the given conditions b : a general relation proved or assumed to hold between mathematical or logical expressions
I agree,and I would actually give Moore's Law less credit than that. I would infer from your definition that, generally, a "law" is something fundamental and immutable that arises from the underlying nature of certain phenomena. Boyle's gas law is a good example: increase the temperature of a gas at constant pressure, and it expands. This is fundamental and can be explained as such.
Moore's "law" is just a relationship built from Intel's marketing engine and economics. Let's say I was rich and decided to start marketing cheap, low-defect silicon. Moore's "law" suddenly changes.
Basically, Moore's law could change at any time (and has) if Intel decides to accelerate their R&D facilities. Or if they decide to invest more in silicon fab facilities. Or if they decided to raise their prices, allowing them to get a lower yield of smaller-featured chips.
When you get right down to it, Moore's law only holds as long as Intel wants it too. Or, if they get more competition that forces them to accelerate their chip release schedule (like the last 5 years thanks to AMD).
Re:It's not even that (Score:3, Interesting)
Study modern processor design. Watch as quantum mechanics beats the crap out of frequency interference and then the two of them gang up on chemistry. After a certain point, the science involved becomes magic.
Recognize Moore's work for how it helps Intel focus on the future. Board meeting: "We have an invention that will multiply preformance by 10x in 5 years." Back of envelope: 2^5 = 32. "I'm sorry, but that's not impressive enough. You'll need to boost preformance by 30x if you want funding."
AMD: "If we want to surpass Intel in the next five years, this is where we must be."
Sure, you could start subsidising the manufacture of silicon on the side and jump into the industry. However, if you want to make it profitable, if you want to succeed on an engineering basis, then you're going to have to play by Moore's rules.
Think you can do it? Today? Tomorrow? Intel has for the last thirty years.
-Brett
Re:It's not even that (Score:2)
Re:It's not a law (Score:1)
Law (noun) [m-w.com]
"6 a : a statement of an order or relation of phenomena that so far as is known is invariable under the given conditions b : a general relation proved or assumed to hold between mathematical or logical expressions"
note: so far as is known
However, if you're one of those people who thinks there's a difference, it is not a 'Law':
(ibid)
"2 a often capitalized : the revelation of the will of God set forth in the Old Testament"
Hopefully this will clear up the confusion surrounding this issue.
Re:It's not a law: Right, it's a visable trend. (Score:3, Interesting)
Couldn't resist replying since i'm on your foes list for god knows what.
Moores law doesn't just apply to silicone, it applies to integrated circuit design in general. If moores law was based purely on the manufacturing techniques at the time, of course it wouldn't hold true in 20 to 30 years.
What we've seen though is a change in manufacturing processes, and with the research going on in quantum computing, light computing, and biological computing, I would speculate that we will see "moores trend" (calling it that because it's not really a law) will continue on course as these advancements are made.
Take for example our use of Si (silicon) for every IC designed today. We use it because of it's strength, and low electrical conductivity. It's a rather large atom though, and we will run out of space eventually using it.
http://www.cs.ubc.ca/cgi-bin/nph-pertab/tab/
But wait! Right above Si on the periodic table of elements is C (carbon) which is roughly
http://www.cs.ubc.ca/cgi-bin/nph-pertab/ta
Now why don't we use carbon based IC's? Well for one thing, carbon does not play well with itself unless you use a lot of heat and pressure (Carbon melting point is 3727c vs Si's 1410c). Secondly we haven't really mass produce the carbon buckyballs/nanotube enough where we could actually use them in place of Si.
Now where was I going with this... Oh yeah..
Basically Moores law will continue to hold true as long as material manufacting keeps up. Silicon has nada to do with it.
Re:It's not a law: Right, it's a visable trend. (Score:2)
When applied to silicone, it is formulated as follows:
"The size of Britney Spears's breasts doubles every 18 years."
Re:It's not a law: Right, it's a visable trend. (Score:2)
1) chips would run cooler and slower than present, but would still be more efficient than their contemporaries (such as comparing a Astro or Crusoe to its speedmates)
or
2) chipmakers would be ignoring this rate and going potentially higher than Moore claimed.
I may be wrong, YMMV, etc.
Re:It's not a law: Right, it's a visable trend. (Score:2)
Sure it is (Score:2)
On my tenth whip. (Score:4, Insightful)
Admonitions against misinterpreting Moore's law are about 3 minutes less old than Moore's law itself, and will probably be the part of Moore's law that outlives the law by 20 years.
Re:On my tenth whip. (Score:2)
That's not right.... (Score:5, Funny)
I tried to read further, but started twitching uncontrollably. How about Mace's Law: "The skill of tech writers halves, and their pride doubles, every 12 months."
I always gave about the same credence to both Moore's Law and Murphy's Law.
Ok, I finished the article. I learned some history, saw some graphs, and care not one bit more about Moore and his infernal Law.
Re:That's not right.... (Score:2, Interesting)
Oh well, at least the rest of the article (hopefully) doesn't appear to take itself quite as seriously as the intro
Jon
Re:That's not right.... (Score:2)
Many of us have written worse during a caffeine-crazed schoolwork rampage, though we were paying good money for the chance.
A practical application of Moore's Law... (Score:4, Interesting)
Re:A practical application of Moore's Law... (Score:2, Interesting)
I wish I was making this up. I'm not.
This again? (Score:2)
Re:This again? (Score:4, Informative)
http://arstechnica.com/archive/news/1045747027.
Re:This again? (Score:2)
Ah, good response. It would have been nice to see this mentioned in the Slashdot lead-in. Good article, too.
All Moores law states is (Score:2, Insightful)
He didn't say just how long his "law" would last, however. He made the huge assumption that intel would keep on keepin on with their technology breakthroughs, and if they perfect that terahertz transistor technology, THEN Moore's law will stay in effect for a little longer
But, something that most people don't take into account (and moore probably didn't either) is the fact that we don't NEED faster computers. We want them. You don't need more than a P4 to do just about anything, but becuase of games that require horsepower, you are required to buy them. Of course theres the server side of things, which is a totally different ballgame. YES, they DO need faster computers as workloads get heavier.
[n8r.n]'s law (Score:5, Funny)
Every 18 [eighteen] months a new faster and more powerful processor is released to the masses that makes my 1Ghz seem obsolete.
Not a sermon, just a thought.
Is it not even simpler? (Score:5, Interesting)
Quite simply, companies expect Moore's law to remain true. Software companies plan product lines in anticipation of processor capability doubling every n years. Processors are going to get improve at this rate, therefore we know how quickly bus performance and peripheral performance need to improve.
Semiconductor manufacturers know this. They plan product lines in a Moore's-law-consistent manner (not necessarily explicity, but surely as a matter of economics). If they're a little behind the curve, more money gets put into keeping up with it... or somebody else steps up and keeps it true. If they're at or ahead, they hold the course.
If someone were to introduce a processor that was 10x the density/speed of current processors, don't you think more resources would then go into peripheral design/heat management/software development to utilize the improvments, rather than continuing to focus on improving the processor?
The reason the law has held so long and seems to be so consistent is that it sets everyone's expectations, and people plan towards those expectations. Not less, not more.
You've all been Jedi mind tricked.
Moore's law - it doesn't actually exist! (Score:3, Insightful)
Yield hasn't been the problem for a while (Score:5, Informative)
This has been achieved by getting a more and more detailed understanding of the processes and eliminating the fundamental sources of the problems. The costs of doing this are immense, but it works. It's striking to look at micrographs of chips today - everything looks so good. No ragged edges anywhere. Think for a moment about what that means. In some of those pictures, you can see atoms, and they're in the right places. Atoms.
It's not like the bad old days of the "purple plague", ceramics with traces of radioactive minerals, or the HP fab with the 4% yield.
Re:Yield hasn't been the problem for a while (Score:2)
Ack! What's wrong?
If cars were like computers (Score:1)
and fit in the palm of your hands.
Re:If cars were like computers (Score:1)
If I was a girl, this sounds a lot like something ELSE that'd be in the palm of my hand.
*click* brrrrrrrrrrrrrmmmmmm
Moore's Law is a special case (Score:4, Informative)
experience curve. To quote an article from the Harvard Business Review
"Building stategy on the experience curve" (HBR March-April 1985, pg 143):
The author then presents a graph showing that Dynamic RAM costs fell at 30%
per every doubling of cumulated output from 1976 to 1984. Besides semiconductors,
the author gives examples from the chemical industry and also the Model T Ford.
BS Alert (Score:1)
This sentence in the article triggered my bullshit alert.
Re:BS Alert (Score:2)
I've noticed... (Score:1)
How did they escape "Moore's" clutches, and more importantly, how do we get them back in?
Zippy the Pinhead on Moore's Law (Score:2)
Yeah, that's great ... (Score:1)
Media mistakes (Score:3, Interesting)
Is it possible that Americans have come to mistrust the media, because the media reporters no longer understand 99% of the subjects on which they report?
Earlier
Perhaps Moore's Law is inversely applicable to media reliability. Every two years the reliability and accuracy of the media is halved. Every two years the ability of the average American to spot the innacuracies is reduced by half.
Ars == Real Geeks (Score:2)
2035? (Score:3, Informative)
IBM announced recently that they will be producing a computer with roughly the same computing power as the human brain, possibly by 2005. That's a pretty significant milestone, if you think about it. Following through with Moore's Law, we should have a computer that is 1000 times more powerful than the human brain as soon as 2020... and a computer that is a million times more powerful than the human brain by 2035.
A million times more powerful than the human brain! What will we do with a computer that powerful? Or, maybe a better question is: What will a computer that powerful do with us?
Kurzweil [kurzweilai.net] has a lot of great articles on this sort of thing.
Here is an interesting link that ties into this (Score:3, Interesting)
These show the history, compare die sizes, etc. and add some context to this article. Had to dig a bit, but I love this kinda stuff. Bet Im not the only one.
Ex post facto laws (Score:3, Interesting)
The first computer I owned was a Compaq Portable (about as portable as a 20" color TV with a handle on it). I paid $3,000 for it - with a 10mb hard drive and a 1200bps Hayes modem.
Today, that same $3,000 - not even adjusting for inflation, and buying only retail equipment, would get me a 2.5+ghz machine with a 20" LCD flat panel. And if I noodge the sales droid enough, toss in a disposable HP printer (as if they make another kind...)
The only concern I have about personal computers these days is... how the heck do I keep track of the exploding volume of information on them?
How do I keep 2,500 family pictures? And find the one of a friend's birthday party?
How do I organize 10 years of letters and emails? And not lose track of the ones from my dad?
Re:Oh the Irony......... (Score:1)
Re:OT, But what the heck... (Score:3, Informative)
S=N/((B*N)+(1-B))
where S is the speedup, N is the number of processors, and B is the percentage of the program that must be serially. The upshot is that as long as B is greater than 0, you'll never get the N-times speedup you'd hope for from throwing N processors at the problem.
It seems a pretty trivial result, but it's basically Gene Amdahl's way of throwing the "multiprocessing will save us" theory back in the faces of its proponents. Multiprocessing is the obvious way to speed things up, but if it won't work on every problem, we'll have to look elsewhere.
Re:OT, But what the heck... (Score:2, Interesting)
This is due to management overhead, ratio of parallelizable to non-parallelizable portions of the task, etc.
Very important stuff to consider when doing multi-threaded/process/tasking and clustered design and development.
Re:OT, But what the heck... (Score:4, Insightful)
Basically, Amdahl's law says that you can only optimize to a point before it becomes pointless. Also, it is often used to demonstrate that it is useless to optimize a single aspect of a system when the other aspects are still unoptimized.
For example, let's say you have a computer that executes something within 10 seconds. 5 of those seconds are spent reading from disk, 5 are spent doing calculations on the CPU.
Now if you upgrade the disk to a disk twice as good, you're gonna get an execution time of 7.5 seconds(5 for CPU, 2.5 for disk). So you gained 2.5 seconds.
Let's say you still think it's too slow, and upgrade the disk again to a disk twice as good. You're now getting an execution time of 6.25 seconds(5 for CPU, 1.25 for disk). You thus gained 1.25 seconds.
You should get the trend here, if you continue upgrading only the disk, it will come to a point where, even by increasing the speed of the disk tenfold, you will only gain small fractions of second on your execution time, and small fractions of second over more than 5 seconds is definitely not a good improvement.
The same reasonning can be applied(this is the original intent of Amdahl's law) to multi-processor machines. Assuming only 50% of a program is runnable in parrallel processing, it comes to a point where adding processors brings very little improvement, even were you to increase the number of processors tenfold. (The explanation for this is left as an exercise to the reader... Hint: it's the same explanation as the disk/cpu above.)
Re:why just the geeks? (Score:4, Funny)
Damn Marketers.
Re:why just the geeks? (Score:2)
ugh.
*hopes that you parse html in your head*
Re:12 or 18? (Score:2)