If a food copier existed - if you could create as much food as you wanted, for the same cost as producing one portion of food - there would be riots in any country that prohibited the copying of food. (and rightly so.)
Actually food copier does exist. Want more apples? Take the seeds plant them and wait a while (the copy process is slow:)).
Unfortunately the cost is still pretty much the same.
But I have heard of farmers being sued for planting genetically modified seeds (which were patented), even by mistake. And there are some African countries that are letting their people starve rather than accept geneticallyu modified food - partly because if their crops are "polluted" with the genetically modifed variety they won't be able to sell their produce in Europe.
The board of enquiry after this accident concluded that "The fall of the bridge was occasioned by the insufficiency of the cross bracing and its fastenings to sustain the force of the gale."
Mistakes are made in construction of bridges and building (i.e. they have bugs too). Sometimes the failures are catastrophic. This is the nature of engineering.
A very enlightining book on this subject is Henry Petroski's "To Engineer is Human".
Yes it is a lot of paperwork, but then another reason why bridges in the 19th century fell down was to do with the fact that the materials being used were not being monitored correctly.
But there was a good reason. At that time we didn't know what to monitor for, never mind that tools to find the problems did not exist (eg. X-rays).
But the bottom line is that bridges had to be build - without the knowledge of materials we have today.
Sure, but many times it's the engineers/programmers who are involved in the time estimates in the first place.
I didn't imply that the programmers do any better at estimating.
However, somewhere along the way we forgot the meaning of the word "estimate":
to judge tentatively or approximately
to determine roughly
So if a task is estimated to take 2 weeks, everyone assumes that it will take exactly two weeks.
Furthermore, the earlier the in the project life the estimates are done the more inaccurate they are, as you know little about the obstacles you'll be facing.
You seem to think about it the wrong way. You don't go and write software and then start to think about its correctness. Rather the program must be designed so that it can be proven to be correct. Big difference there.
OK then. Given the http spec can write a provably correct web server?:-)
Well, the point of the (in this case formal) specification is that it's a lot simpler than the implementation.
I disagree. I think that formal specs are much harder to write - that's why nobody does it.
In fact, source code is really just a very precise specification of what the computer has to do. It's so precise that it can be translated into an executable form automatically.:-)
It really escapes me why proving SW correctness for properly designed software should be intractable. While it's true that formal methods for correctness proving may not yet be advanced enough, there's no reason why they couldn't be.
I don't have a formal proof, but some strong intuition. First of all to prove software correct means that you have to start with a spec that is precise enough. This eliminates about 99% of all projects.
Secondly, if you have a spec you have to show that the software text you wrote produces results as specified. This feels like proving that two programs are equivalent - which I believe is an undecidable problem.
Finally, if you factor in the interactions with the real world, you wind up with a deterministic but a highly non-linear system. These tend to give rise to chaotic behavior, which while deterministic is not at all predictable.
If I follow your train of thought to its natural conclusions, I should arrive at the idea that when building a bridge, it is not necessary to prove that the finished construction will be able to withstand the load that it bears. Would you agree with that assessment?
No. But you can only use the science you know to help you proving that the thing will stand up. Furthermore, spec for briges tend to be pretty clear.
In any case, if you look into history of bridge building you'll find that for the longest time the formula for the strength of cantilever beam was wrong (this guy Galileo got it wrong). So when the engineers building bridges reduced the safety factor (to speed up construction and reduce cost) bridges started falling down.
In 19th centuary England a lot of iron bridges collapsed, despite the fact that it was "proved" that they were strong enough. Metal fatigue was not understood then.
Lastly, your request for a proof exemplifies my point. You cannot offer such a proof and that is why Apache has to be patched.
Why not? At least you have a spec for a HTTP protocol, which is pretty precise as such spec go.
If you cannot offer a proof in the case where a precise spec exists, what hope is there for other software?
Finally at most you can prove with a program that the program works according to its specification.
But what about the correctness of the specification itself?
Unfortunately, computer science is still in its relative infancy
Exactly. But what we are talking about is software engineering. Engineers are paid to build things that work. They are free to use whatever helps them in their tasks, if there is good science they use it. If there is no science they have to hack.
Try telling your next customer that implementing his system will take 50 years, because the science of translating his imprecise requirements into software hasn't been invented yet.
It is widely known that few significant development projects, if any, finish successfully, on time, and within budget.
What bothers me about statements like this, is that no one is suggesting that perhaps our estimation and budgeting methods are off.
What if someone scheduled one week and allocate $100 for design and construction of a skyscraper, and when the engineers failed to deliver, who should be blamed? The engineers?!
To produce bugless software we need to start with software designs that are provably correct and then produce code that is provably in line with the design.
This is easy to say, but it is impossible in practice, except for a small set of problems (like computing prime numbers).
Furthermore, software engineering is engineering, so you have to produce something within a reasonable cost.
As an exersize please submit a proof that Apache web server implements HTTP correctly.
Right in my home network I had to prioritze RTP packets (VoIP) so that other people in the house couldn't screw up my phone conversations when saturating my uplink or downlink. The same can be true on a national backbone, especially in failure conditions where you will get links that saturate.
Do you really want to make it easy for FBI, CIA, KGB, you local police etc. to tell which packets are VoIP packets?
So if service jobs, creative jobs, research jobs, and development jobs all get outsourced... What's left and why, exactly, will the economy survive?
We won't have to work. We will live of our 401K because the shares of all these companies will soar now that they cut costs and increased profits. I'm planning to retire on my 100 shares of CSCO.
Not that the courts really care about the science behind it. Instead, they'd demand the source be opened for inspection. This would be ok for opensource developers, but for a small proprietary business, you might as well commit corporate suicide or settle out of court. Especially if your way is better than the patented version.
But patent protects the idea (i.e. the algorithm), not the expression. So, the source code could be quite different (for example I'll write in Lisp and you in C) but still infringing.
The question is whether they both compute the same thing. In general this is an undecidable problem (in the same sense as the Halting Problem is undecidable).
3: Given a single patented algorithm, its impossible to tell if a given program is using THAT algorithm, or some other method of performing the same task. [...]
Actually, as I recall the problem of deciding if one algorithm is equivalent to another is undecidable. Isn't it?
Plagiarism is passing somebody else's work off as your own,
Naturally I would never pass this work as my own. And I'm quite happy to give credit where credit is due.
I think the school culture is bit out of sync with the working world. In school cooperation is called "cheating" in the working world it's being "team player".
Unfortunately, students often get away with petty plagiarism all through college, and then move on to graduate school or professional careers where sources are more easily identified, and the penalty for plagiarism tends to be much heavier.
I don't know. In my job I use a lot of open source libraries and "plagiarize" code from other people's programs. Is this really bad?
I think I'd get punished more for trying to re-invent the wheel each time.
I'll tell you, it's pervasive. Since then, I've not found one person who can give a cohesive definition at this company. And yet, it's supposed to be my driving force and ultimate goal.
They probably used BS Generator to come with all this.
Today I will unleash my spiritual consciousness and then leverage my universal divinity to manifest my core realization. There, I said it!
Note that the ethernet port is so slow as to be nearly useless. It took me about 80 minutes to sync about 2GB onto the thing over ethernet. And trust me, it isn't my network cabling screwing it up.
80 minutes for 2Gig seems excessive. My music collection in on a Samba drive, so even when I use the USB connection I go over the ethernet to read the files.
So far I have over 12Gig of music on the player. What I do now is to load small collections of new files, as I rip more CDs. This seems fast enough over the network connection.
I'm happy not to have to boot into Windows to do it.
Slashdot Mirror
Correct. But copyright violation is not theft. If it were, we wouldn't need new laws. Theft is already illegal.
Read about the use of words here
Right. Actually the idea came from Bell Labs and the system was called Unix.
Actually food copier does exist. Want more apples? Take the seeds plant them and wait a while (the copy process is slow :)).
Unfortunately the cost is still pretty much the same.
But I have heard of farmers being sued for planting genetically modified seeds (which were patented), even by mistake. And there are some African countries that are letting their people starve rather than accept geneticallyu modified food - partly because if their crops are "polluted" with the genetically modifed variety they won't be able to sell their produce in Europe.
Partly because of fear of IP protection.
gzip britney.mp3
Mistakes are made in construction of bridges and building (i.e. they have bugs too). Sometimes the failures are catastrophic. This is the nature of engineering.
A very enlightining book on this subject is Henry Petroski's "To Engineer is Human".
But there was a good reason. At that time we didn't know what to monitor for, never mind that tools to find the problems did not exist (eg. X-rays).
But the bottom line is that bridges had to be build - without the knowledge of materials we have today.
I didn't imply that the programmers do any better at estimating.
However, somewhere along the way we forgot the meaning of the word "estimate":
to judge tentatively or approximately
to determine roughly
So if a task is estimated to take 2 weeks, everyone assumes that it will take exactly two weeks.
Furthermore, the earlier the in the project life the estimates are done the more inaccurate they are, as you know little about the obstacles you'll be facing.
OK then. Given the http spec can write a provably correct web server? :-)
Well, the point of the (in this case formal) specification is that it's a lot simpler than the implementation.
I disagree. I think that formal specs are much harder to write - that's why nobody does it.
In fact, source code is really just a very precise specification of what the computer has to do. It's so precise that it can be translated into an executable form automatically. :-)
I don't have a formal proof, but some strong intuition. First of all to prove software correct means that you have to start with a spec that is precise enough. This eliminates about 99% of all projects.
Secondly, if you have a spec you have to show that the software text you wrote produces results as specified. This feels like proving that two programs are equivalent - which I believe is an undecidable problem.
Finally, if you factor in the interactions with the real world, you wind up with a deterministic but a highly non-linear system. These tend to give rise to chaotic behavior, which while deterministic is not at all predictable.
No. But you can only use the science you know to help you proving that the thing will stand up. Furthermore, spec for briges tend to be pretty clear.
In any case, if you look into history of bridge building you'll find that for the longest time the formula for the strength of cantilever beam was wrong (this guy Galileo got it wrong). So when the engineers building bridges reduced the safety factor (to speed up construction and reduce cost) bridges started falling down.
In 19th centuary England a lot of iron bridges collapsed, despite the fact that it was "proved" that they were strong enough. Metal fatigue was not understood then.
Lastly, your request for a proof exemplifies my point. You cannot offer such a proof and that is why Apache has to be patched.
Why not? At least you have a spec for a HTTP protocol, which is pretty precise as such spec go. If you cannot offer a proof in the case where a precise spec exists, what hope is there for other software?
Finally at most you can prove with a program that the program works according to its specification. But what about the correctness of the specification itself?
Unfortunately, computer science is still in its relative infancy
Exactly. But what we are talking about is software engineering. Engineers are paid to build things that work. They are free to use whatever helps them in their tasks, if there is good science they use it. If there is no science they have to hack.
Try telling your next customer that implementing his system will take 50 years, because the science of translating his imprecise requirements into software hasn't been invented yet.
What bothers me about statements like this, is that no one is suggesting that perhaps our estimation and budgeting methods are off.
What if someone scheduled one week and allocate $100 for design and construction of a skyscraper, and when the engineers failed to deliver, who should be blamed? The engineers?!
This is easy to say, but it is impossible in practice, except for a small set of problems (like computing prime numbers).
Furthermore, software engineering is engineering, so you have to produce something within a reasonable cost.
As an exersize please submit a proof that Apache web server implements HTTP correctly.
Do you really want to make it easy for FBI, CIA, KGB, you local police etc. to tell which packets are VoIP packets?
Exactly!!!!
We won't have to work. We will live of our 401K because the shares of all these companies will soar now that they cut costs and increased profits. I'm planning to retire on my 100 shares of CSCO.
Pardon me if my sarcasm is showing...
But patent protects the idea (i.e. the algorithm), not the expression. So, the source code could be quite different (for example I'll write in Lisp and you in C) but still infringing.
The question is whether they both compute the same thing. In general this is an undecidable problem (in the same sense as the Halting Problem is undecidable).
Actually, as I recall the problem of deciding if one algorithm is equivalent to another is undecidable. Isn't it?
Naturally I would never pass this work as my own. And I'm quite happy to give credit where credit is due.
I think the school culture is bit out of sync with the working world. In school cooperation is called "cheating" in the working world it's being "team player".
I don't know. In my job I use a lot of open source libraries and "plagiarize" code from other people's programs. Is this really bad?
I think I'd get punished more for trying to re-invent the wheel each time.
They probably used BS Generator to come with all this.
Today I will unleash my spiritual consciousness and then leverage my universal divinity to manifest my core realization. There, I said it!
80 minutes for 2Gig seems excessive. My music collection in on a Samba drive, so even when I use the USB connection I go over the ethernet to read the files.
So far I have over 12Gig of music on the player. What I do now is to load small collections of new files, as I rip more CDs. This seems fast enough over the network connection.
I'm happy not to have to boot into Windows to do it.