No, it's no more your choice to develop unfree software if you wish than it is your choice to stab whoever you choose with your own knife.
All the fruits of all human endeavour belong to all of humanity. You may have written that software, but it does not belong to you: it belongs to everyone. As a human being, you have certain rights. Other people have exactly the same rights too. Your rights translate to other people's obligations, and other people's rights translate to your obligation. As a human being, your obligation is to improve -- or at least not worsen, such as by denying an individual their rights -- the lot of humanity as a whole.
Each of us has four basic rights which spring directly from the existence of software. These are: the right to ENJOY the use of software without restriction, the right to STUDY how software works, the right to SHARE software with their neighbours to improve the lot of humanity as a whole and the right to ADAPT software to their needs. These rights, in turn, translate to an obligation incumbent upon everyone who creates software to uphold the rights of its users.
If you do not allow me to make copies of software for other people, or if you do not allow me access to the source code and thereby prevent me from studying and adapting software, then that is an example of you imposing your will upon me. I consider that to be an act of violence, and I reserve the right to use reasonable force to defend myself.
I advocate no loss of life, nor damage to tangible property; only to false "intellectual property".
You do realise, don't you, that you just insulted the intelligence of everyone who knows more than one means to accomplish a given end? Absit omen someone should learn that the end is independent of the means. For crying out loud, they might even realise that that is the right place to stick an abstraction layer, not just where it looks pretty!
You seem to have a very narrow view -- certainly no broader than Microsoft's paid shills -- if you really think that learning to use one software product precludes you from using anything else. Well, even Microsoft Office isn't consistent from one version to another -- default behaviours change subtly with each successive release. But that's obviously fine as far as you're concerned.
In the absolute worst case, the companies will simply have to switch to the Open Source alternatives that their new employees already know and love. It's not like it's going to cost them anything. Now, when they do switch, and find out that they could have been saving money all along, then things are going to get very interesting.....
I think the LGPL will eventually turn out to be a huge tactical mistake
Agreed. I think the GNU project have gone soft lately. I hope the next GNU C library is straight GPL, with no permission even for linking from unfree software. Can you fork an LGPL project and release it straight GPL, or does the LGPL insist for all derivative works also to lie back and think of England?
Have you tried simply posting the empty packaging back to them, with no return address, labelled "POSTAGE TO BE PAID BY RECIPIENT" and for the attention of the ISO 14001 Compliance Manager ?
Which is why I believe, and have always believed, that production standards for imported goods should satisfy the same criteria as locally-made goods -- not only in terms of the product itself {e.g. no 110 volt appliances in countries with 230 volt mains}, but also in terms of the production process. Manufacturers in Western countries where there are things like health and safety, workers' rights and pollution control can't hope to compete on price with manufacturers in third world countries where there aren't such niceties. If goods are being made in a factory where nobody is allowed to join a trade union, they should not be imported into any country where trade unions are permitted. If polluting or dangerous practices are employed in the manufacture of goods, they should not be imported into any country where those practices would not be allowed.
Otherwise, offshore outsourcing is just a way to export things we like to pretend we aren't doing.
Clarification, please. Are we now treating the Hammersmith and City Line as being a distinct entity from the Metropolitan Line, or are we still going by the "old" map?
There is definitely something in that. I was talking to a woman friend a few years ago and she mentioned she was experimenting with reusable alternatives to sanitary towels and tampons. Natural sea sponges are good and absorbent but they're also made from dead animals; foam rubber artificial sponges are less absorbent; cotton terry towelling is bulky. The conversation eventually got turned around to "Could you eat a diet that gave you all the nutrients your body required and also eliminated, or at least minimised your use of toilet paper?"
I don't think either of us ever tried a TP-free diet in earnest, and I've lost touch with her since then.
All urinals in Britain flush automatically. Brits abroad generally don't flush after peeing because they don't expect to have to. I have also seen non-contact WC flushing controls in some UK public facilities: this consists of a motion sensor in front of which you wave your hand, and which operates a solenoid which pulls up the flush mechanism. {This is using the rest-of-world flush mechanism, only recently legalised in the UK, where a round-bottomed stopper is displaced from a hole in the base of the cistern and floats on the discharging water until the cistern is empty. Older UK installations used a syphon to discharge the cistern and had the advantage that holding down the flush lever would not cause continuous emptying: the syphon could only be started with the cistern full.}
As for water-saving WC cisterns, I recently had a new WC installed with a close-coupled, 6 litre cistern and I find that even on half flush it will usually dispose of "big business". The WC basin and flushing cistern are designed together as a system: it would be foolish to expect a 6L cistern to properly flush a WC designed for a 9L flush.
In general, a washdown WC {where the waste is simply pushed out of the basin by the flushwater: common in UK and Europe} will use less water, and be less prone to blockage, than a syphonic-action WC {where a partial vacuum is created in the trap and the waste is drawn out of the basin: common in USA, not to be confused with the UK system of using a syphon to empty the cistern into a [usually] washdown basin}.
That's a potential problem with any mechanical combination lock: if the turny bit of the mechanism isn't properly decoupled from the locky bit, then you can identify a partial solution and so decrease the search space. But if it is too well decoupled, then the lock will give false positives or false negatives. Some of those cheap briefcase locks are actually quite poorly decoupled: you can feel just a little bit more movement when any one of the wheels is "solved". {Which is why that episode of Only Fools and Horses was a bit unrealistic.} Even although this can take more than a second a try, just getting the search down from 1000 tries to 30 tries is a good improvement in its own right.
Or at least provide a definition when first introducing an acronym. Besides the traditional method (i.e. brackets), in HTML, you can do something along the lines of IIS - which renders distinctively from general text, and shows a tooltip on hover.
What rather took the edge off discovering that, for me, was that I'd already come up with a rather convoluted bit of DHTML to do exactly the same effect.
Navigate to some writeable directory under/mnt/. Useful commands {this is by no means a full unix primer}: ls to list contents of directory. Blue is a directory, green is executable, red is compressed, cyan is a shortcut, magenta is a media file, yellow is a device, white is a boring old file.cd to change directory, cd.. to go to parent directory, mkdir to make a new directory. TAB key auto-completes a filename after typing first few chars, cursor up/down to go back/forward through command history. Remember there are 52 letters in the alphabet.
# cdparanoia -B
This procedure is believed to get around all known DRM, even on PCs infected by the Sony Rootkit.
You can buy a briefcase with two separate, three-digit combination locks in any stationery store, and it won't cost you a lot of money. Invest in one as a "prop" for this demonstration. Have your co-worker set a combination for the left-hand lock and a different combination for the right-hand lock, lock the case and spin the wheels randomly. Now, there are 1000 possible combinations for the LH lock and 1000 possible combinations for the RH lock, giving you 1000000 possible combinations. If you can try one combination a second, it could take you up to 9 months to get into the case. Right? {If your co-worker actually believes this, perhaps it would be simplest just to have them put to S-L-E-E-P}.
Once you have cracked the left-hand lock {which will take at most 1000 tries - 17 minutes} you are free to concentrate on the RH lock {which also will take at most 1000 tries}. You don't have to try anymore combinations on the LH lock. So you can open the briefcase in a maximum of 2000 tries, or just over half an hour. The key fact that makes this possible is that the two locks are independent: you can undo one while the other remains fastened. The combined keyspace is then the sum, not the product,of the two keyspaces.
If the encryption operation adds a predictable header to the ciphertext {for example, BEGIN OPHIOL ENCRYPTED MESSAGE} {and most of them do} then you have something to look for that will let you know when you have cracked the first layer of encryption -- in effect, popped open the left-hand lock.
Encryption and decryption are just mathematical functions. Let F(K,x) be a generalised function describing the encryption algorithm, where K is the key and x is the plaintext. We can collapse this to a simpler function K(x). Let K'(x) represent F'(K,x) i.e. the inverse of K(x).
Now your double encryption is something like K2(K1(x)). But this is still just some function of x. It's possible {maybe not necessarily certain, depending upon the algorithm employed} that there exists K3 such that F(K3,x) == K2(K1(x)); in other words, the combined encryption is equivalent to an encryption operation using the same algorithm but some third key K3, which is in the same keyspace as K1 and K2. If this is the case, then our attacker need only discover K'3(x), which will crop up anyway among the possibilities in a brute-force attack. So for at least some encryption algorithms, there is no additional security to be had by doubly encrypting.
The problem with simple ROT and EOR cipher schemes is that, for any K1(x) and K2(x) there exists a K3(x) such that K3(x) = K2(K1(x)). So encrypting something twice (first with K1 and then encrypting the ciphertext with K2) is really only the same as encrypting it once with a different key.
But notice that this mapping is of the same kind. Therefore, the double encryption operation is exactly equivalent to a single encryption operation: an attacker need never actually discover K1 or K2 to break the combined cipher. Notice also that this does not depend on K2(K1(x)) == K1(K2(x)): it holds also for simple random alphabet scrambling {i.e. the generalised set of all 26! 1:1 mappings of the alphabet}.
Example: K3(x) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => NXZGMRALUCFWHTYDKVEQSBIJOP.
K4(x) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => DLYHSVWXGMREKTJUZBIOANQCFP.
K4(K3(x)) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => TCPWKBDEAYVQXOFHRNSZILGMJU {a mapping of the same kind}
but K3(K4(x)) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => GWOLEBIJAHVMFQCSPXUYNTKZRD {a different mapping but still of the same kind}.
I believe {I cannot think of, but would love to see, a counterexample} this can be generalised to any set of simple one-to-one mappings where the sets of permitted values at the input and output are equivalent: Km(Km-1(.....K2(K1(x)).....)) == Kn(x).
Even if they have to pay for the whole thing being developed in house, it does create local jobs and helps build technical skills (a worthy investment in itself.)
That is a massively important thing in and of itself. Local programmers contribute to the local economy by paying local taxes, spending money in local shops, drinking in local bars, eating in local restaurants and taking their friends and family to local tourist attractions. The money stays around, in one form or another; the local economy is stable and inflation is low. Also, the overall skillset of the local population is enhanced, so the investment has some sort of scrap value in the form of what people can now do.
Money spent on imported, proprietary software is effectively lost for all time. The scrap value of proprietary software is limited to a few kilos of paper for pulp, and some CDs for.......... well, whatever it is that they make out of used CDs.
Nothing - provided you are using the latest version. It's fast, it looks good, it supports CSS (even passing ACID2), it has tabs, it accepts Mozilla-style extensions. In fact, it does everything Opera does -- but, unlike Opera, you get the source code.
Konqueror 2.X was a poor imitation of Internet Explorer (without the vulnerabilities). But things have moved on a lot since those days..... except IE.....
Microsoft tolerated piracy because they knew damn well it was hurting smaller companies more than it was hurting Microsoft. Selling an office suite for a tenth of the "official" asking price of MS Office is irrelevant if the "street" price of MS Office is £nil. Basic human nature -- specifically, the hunter-gatherer instinct, a remnant from caveman times which lives on in us today and explains why some people think paying full price is cheating, why some people will consider a pair of shoes a great bargain even if they do not fit and why your dog prefers food stolen from someone else's plate -- suggests that the more expensive product will get pirated and the less expensive product will get ignored. If MS Office had not been so easy to pirate, then less expensive, competing products would have gained a greater market share.
MS would rather you were using pirated Microsoft software than Open Source -- after all, if you're using pirated MS software, there's at least a small chance that you can be strong-armed into buying legitimate MS software {the other way to get legal would be to go Open Source, which has happened but is admittedly a rare occurrence}. Whereas, there's no reason why anyone who is already happy with Open Source would want to change to Microsoft.
I thought MS Office included an almost-complete OS and filesystem API anyway, to compensate for various brokennesses in Windows -- Office certainly seems to have its own file requester code, though it's only obvious when you install a new Office on top of an older Windows.
Anyway, if MS Office ever starts supporting ODF, then expect significant advances in Open Source office suites -- the developers will finally be able to do other things beside reverse-engineer the latest.doc format. I have high hopes for the next KOffice.
And yes, there is a minimum pressure the tires must be to hold the weight of the car, but 40psi in the tires does not mean 40 pounds of pressure per each square inch of the device's measurement... again, this is the in-tire pressure.
Maybe things aren't equal if you insist to measure them with your stupid units; but if you use proper measuring units, things make so much more sense. The pressure in the tyres {200 000 Pa in my example} is the force in Newtons acting on each square metre of the surface of the tyre. That must be balancing the 10 000 N weight of the car exactly, since the car is not going anywhere: if there was an unbalanced force acting in some direction, then something would move.
ome of the air in the tire is helping exert the upward pressure on the vehicle, but the weight is also being born by the superstructure of the tire itself and other factors.
No. Tyre walls have almost no compressive strength -- they would just collapse if you tried to squash them. They have tensile strength. What you have to do is stretch them first {by filling the tyres with air at a higher pressure than the air outside}. Then they will have an apparent compressive strength -- because "squashing" them when they are already stretched is really just stretching them less.
You could have a 40psi tire or a 50psi tire, but that doesn't directly increase or decrease how much the items underneath are bearing by 10 psi (if you put a scale underneath, increasing or decreasing tire pressure does not make the scale show a different measurement. That's weight, which I think is where the article got a bit wrong using PSI instead of pounds).
If you put a pair of scales under each tyre, all the readings will add up to 1000kg. They may not all read exactly 250kg because the weight of the car probably is not perfectly evenly distributed. You're right that increasing the pressure of one tyre will not change the reading on the scales {except to the extent that the weight will be redistributed a little, but this will be negligible}, but it will reduce the amount of tyre in contact with the surface of the scales. More Pascals of pressure in the tyre as shown by the manometer attached to the tyre pump will manifest themselves as the same number of Newtons {which come from the weight of the car, which hasn't changed; multiplied by some constant due to weight distribution, which hasn't changed so as you'd notice} distributed over fewer square metres {smaller contact area}.
You will find, if you place scales under each wheel, and measure the surface area of each tyre which is in contact with the scales and the pressure in each tyre, that the tyre pressure in Pascals will be equal to the mass showing on the scales in kg., times g, divided by the area of contact in square metres.
I had always thought the addicting property of opiates was integral with the pain-relieving property. As I understand it it, it works something like this:
Morphine {and that includes derivatives such as heroin} basically binds to the same receptors as endorphins, the body's natural pain-relievers {and feelgood chemicals: a dose of endorphins is your body's usual reward for behaviour deemed to be of evolutionary benefit}. Your body produces extra endorphins in times of trauma; but there is usually some level of endorphins in your system, keeping you from feeling the ends of your bones scraping against one another or the pressure of the blood in your arteries. Some people -- especially kids -- deliberately inflict pain on themselves to crank up their endorphin production.
Introducing artificial substances interferes with the body's self-regulatory systems, leading to less endorphin production. Therefore, when you come down off morphine / heroin / methadone, your background endorphin level is lower than it should be -- and as a consequence, you begin to feel the sensations of your body working normally -- which would normally be masked by endorphins -- as pain. Your joints are painful, the movement of food through your digestive system {which has just started up again} is painful, your blood flow is painful, the increasing pressure in your bladder is painful.
Most people can't wait long enough for their endorphin production to get back to normal levels, and instead take another dose just to get rid of the pain of existence. This, of course, is liable to undo the work of restarting endorphin production -- and that is why morphine is addictive.
So how does this new stuff work? If it's got a similar enough structure to morphine that it binds to endorphin receptors, then surely it will slow or block endorphin production just as much as any other flavour of junk? The only way I can see it possibly working is if its pain-relieving property wears off at exactly the same rate that the body naturally begins producing endorphins from scratch. But isn't that a person-to-person variable?
Yeah, and by measuring the distance between molten chunks of chocolate in a microwave oven, you're actually measuring the speed of uwaves, not the speed of light.
Hint: go read some physics.
Let's suppose the air in the car's tyres is at 200 000 Pa, and the car weighs 1000kg, and for simplicity we'll assume g=10 ms-2. (If you're going to do proper science, you might as well use proper measuring units.) Now the weight of the car is 10000 Newtons and the only thing supporting it is the air in the tyres. So, since every action has an equal and opposite reaction, you must have 10 000 Newtons pressing upwards on the car through the air in the tyres. And since the pressure in a fluid acts equally in all directions, you have 10 000 Newtons pressing down on the road through the air in the tyres. We know the pressure of the air in the tyres is 200 000 Pa, so the area in contact with the road must be 10 000 / 200 000 = 10 / 200 = 0.05 m2. If we multiply that by 10000 we get 500cm2, or 125cm2 per tyre, which is not unreasonable.
What they are measuring in kilogrammes is really their mass {which is a property of an object which relates to how much matter it contains, and is measured in kilogrammes}, not their weight {which is a force exerted by an object due to gravitational attraction, and is directly dependent upon its mass, and is measured in Newtons}.
At least, if they were using a beam balance, they would really be measuring their mass {assuming that the value of g is the same for the person being weighed and the counterweight[s]}. If they were using a spring balance, then they would actually be measuring their weight {in Newtons} and dividing it by some assumed value for g to convert it to an approximate mass. g is about 10 ms-2 over most of the Earth's surface; and not too far off pi ** 2 for that matter, which is handy sometimes for quick pendulum calculations: T = As Near As Damn Is To Swearing 2 * sqrt(l).
Slashdot Mirror
No, it's no more your choice to develop unfree software if you wish than it is your choice to stab whoever you choose with your own knife.
All the fruits of all human endeavour belong to all of humanity. You may have written that software, but it does not belong to you: it belongs to everyone. As a human being, you have certain rights. Other people have exactly the same rights too. Your rights translate to other people's obligations, and other people's rights translate to your obligation. As a human being, your obligation is to improve -- or at least not worsen, such as by denying an individual their rights -- the lot of humanity as a whole.
Each of us has four basic rights which spring directly from the existence of software. These are: the right to ENJOY the use of software without restriction, the right to STUDY how software works, the right to SHARE software with their neighbours to improve the lot of humanity as a whole and the right to ADAPT software to their needs. These rights, in turn, translate to an obligation incumbent upon everyone who creates software to uphold the rights of its users.
If you do not allow me to make copies of software for other people, or if you do not allow me access to the source code and thereby prevent me from studying and adapting software, then that is an example of you imposing your will upon me. I consider that to be an act of violence, and I reserve the right to use reasonable force to defend myself.
I advocate no loss of life, nor damage to tangible property; only to false "intellectual property".
Bollocks.
.....
You are talking out of your arse.
You do realise, don't you, that you just insulted the intelligence of everyone who knows more than one means to accomplish a given end? Absit omen someone should learn that the end is independent of the means. For crying out loud, they might even realise that that is the right place to stick an abstraction layer, not just where it looks pretty!
You seem to have a very narrow view -- certainly no broader than Microsoft's paid shills -- if you really think that learning to use one software product precludes you from using anything else. Well, even Microsoft Office isn't consistent from one version to another -- default behaviours change subtly with each successive release. But that's obviously fine as far as you're concerned.
In the absolute worst case, the companies will simply have to switch to the Open Source alternatives that their new employees already know and love. It's not like it's going to cost them anything. Now, when they do switch, and find out that they could have been saving money all along, then things are going to get very interesting
Have you tried simply posting the empty packaging back to them, with no return address, labelled "POSTAGE TO BE PAID BY RECIPIENT" and for the attention of the ISO 14001 Compliance Manager ?
Which is why I believe, and have always believed, that production standards for imported goods should satisfy the same criteria as locally-made goods -- not only in terms of the product itself {e.g. no 110 volt appliances in countries with 230 volt mains}, but also in terms of the production process. Manufacturers in Western countries where there are things like health and safety, workers' rights and pollution control can't hope to compete on price with manufacturers in third world countries where there aren't such niceties. If goods are being made in a factory where nobody is allowed to join a trade union, they should not be imported into any country where trade unions are permitted. If polluting or dangerous practices are employed in the manufacture of goods, they should not be imported into any country where those practices would not be allowed.
Otherwise, offshore outsourcing is just a way to export things we like to pretend we aren't doing.
Clarification, please. Are we now treating the Hammersmith and City Line as being a distinct entity from the Metropolitan Line, or are we still going by the "old" map?
There is definitely something in that. I was talking to a woman friend a few years ago and she mentioned she was experimenting with reusable alternatives to sanitary towels and tampons. Natural sea sponges are good and absorbent but they're also made from dead animals; foam rubber artificial sponges are less absorbent; cotton terry towelling is bulky. The conversation eventually got turned around to "Could you eat a diet that gave you all the nutrients your body required and also eliminated, or at least minimised your use of toilet paper?"
I don't think either of us ever tried a TP-free diet in earnest, and I've lost touch with her since then.
All urinals in Britain flush automatically. Brits abroad generally don't flush after peeing because they don't expect to have to. I have also seen non-contact WC flushing controls in some UK public facilities: this consists of a motion sensor in front of which you wave your hand, and which operates a solenoid which pulls up the flush mechanism. {This is using the rest-of-world flush mechanism, only recently legalised in the UK, where a round-bottomed stopper is displaced from a hole in the base of the cistern and floats on the discharging water until the cistern is empty. Older UK installations used a syphon to discharge the cistern and had the advantage that holding down the flush lever would not cause continuous emptying: the syphon could only be started with the cistern full.}
As for water-saving WC cisterns, I recently had a new WC installed with a close-coupled, 6 litre cistern and I find that even on half flush it will usually dispose of "big business". The WC basin and flushing cistern are designed together as a system: it would be foolish to expect a 6L cistern to properly flush a WC designed for a 9L flush. In general, a washdown WC {where the waste is simply pushed out of the basin by the flushwater: common in UK and Europe} will use less water, and be less prone to blockage, than a syphonic-action WC {where a partial vacuum is created in the trap and the waste is drawn out of the basin: common in USA, not to be confused with the UK system of using a syphon to empty the cistern into a [usually] washdown basin}.
That's a potential problem with any mechanical combination lock: if the turny bit of the mechanism isn't properly decoupled from the locky bit, then you can identify a partial solution and so decrease the search space. But if it is too well decoupled, then the lock will give false positives or false negatives. Some of those cheap briefcase locks are actually quite poorly decoupled: you can feel just a little bit more movement when any one of the wheels is "solved". {Which is why that episode of Only Fools and Horses was a bit unrealistic.} Even although this can take more than a second a try, just getting the search down from 1000 tries to 30 tries is a good improvement in its own right.
Or at least provide a definition when first introducing an acronym. Besides the traditional method (i.e. brackets), in HTML, you can do something along the lines of IIS - which renders distinctively from general text, and shows a tooltip on hover.
What rather took the edge off discovering that, for me, was that I'd already come up with a rather convoluted bit of DHTML to do exactly the same effect.
No, I meant EOR. I learnt on 6502, not Z80 :)
- Download Slax
- Boot up with slax copy2ram
- Login as root, password toor
- Swap Slax CD with music CD
- Navigate to some writeable directory under
/mnt/. Useful commands {this is by no means a full unix primer}: ls to list contents of directory. Blue is a directory, green is executable, red is compressed, cyan is a shortcut, magenta is a media file, yellow is a device, white is a boring old file.cd to change directory, cd .. to go to parent directory, mkdir to make a new directory. TAB key auto-completes a filename after typing first few chars, cursor up/down to go back/forward through command history. Remember there are 52 letters in the alphabet. - # cdparanoia -B
This procedure is believed to get around all known DRM, even on PCs infected by the Sony Rootkit.You can buy a briefcase with two separate, three-digit combination locks in any stationery store, and it won't cost you a lot of money. Invest in one as a "prop" for this demonstration. Have your co-worker set a combination for the left-hand lock and a different combination for the right-hand lock, lock the case and spin the wheels randomly. Now, there are 1000 possible combinations for the LH lock and 1000 possible combinations for the RH lock, giving you 1000000 possible combinations. If you can try one combination a second, it could take you up to 9 months to get into the case. Right? {If your co-worker actually believes this, perhaps it would be simplest just to have them put to S-L-E-E-P}.
Once you have cracked the left-hand lock {which will take at most 1000 tries - 17 minutes} you are free to concentrate on the RH lock {which also will take at most 1000 tries}. You don't have to try anymore combinations on the LH lock. So you can open the briefcase in a maximum of 2000 tries, or just over half an hour. The key fact that makes this possible is that the two locks are independent: you can undo one while the other remains fastened. The combined keyspace is then the sum, not the product,of the two keyspaces.
If the encryption operation adds a predictable header to the ciphertext {for example, BEGIN OPHIOL ENCRYPTED MESSAGE} {and most of them do} then you have something to look for that will let you know when you have cracked the first layer of encryption -- in effect, popped open the left-hand lock.
That depends.
Encryption and decryption are just mathematical functions. Let F(K,x) be a generalised function describing the encryption algorithm, where K is the key and x is the plaintext. We can collapse this to a simpler function K(x). Let K'(x) represent F'(K,x) i.e. the inverse of K(x).
Now your double encryption is something like K2(K1(x)). But this is still just some function of x. It's possible {maybe not necessarily certain, depending upon the algorithm employed} that there exists K3 such that F(K3,x) == K2(K1(x)); in other words, the combined encryption is equivalent to an encryption operation using the same algorithm but some third key K3, which is in the same keyspace as K1 and K2. If this is the case, then our attacker need only discover K'3(x), which will crop up anyway among the possibilities in a brute-force attack. So for at least some encryption algorithms, there is no additional security to be had by doubly encrypting.
The problem with simple ROT and EOR cipher schemes is that, for any K1(x) and K2(x) there exists a K3(x) such that K3(x) = K2(K1(x)). So encrypting something twice (first with K1 and then encrypting the ciphertext with K2) is really only the same as encrypting it once with a different key.
Example: K1(x) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ onto DEFGHIJKLMNOPQRSTUVWXYZABC.
K2(x) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ onto LMNOPQRSTUVWXYZABCDEFGHIJK.
K2(K1(x)) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ onto OPQRSTUVWXYZABCDEFGHIJKLMN.
But notice that this mapping is of the same kind. Therefore, the double encryption operation is exactly equivalent to a single encryption operation: an attacker need never actually discover K1 or K2 to break the combined cipher. Notice also that this does not depend on K2(K1(x)) == K1(K2(x)): it holds also for simple random alphabet scrambling {i.e. the generalised set of all 26! 1:1 mappings of the alphabet}.
Example: K3(x) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => NXZGMRALUCFWHTYDKVEQSBIJOP.
K4(x) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => DLYHSVWXGMREKTJUZBIOANQCFP.
K4(K3(x)) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => TCPWKBDEAYVQXOFHRNSZILGMJU {a mapping of the same kind}
but K3(K4(x)) maps ABCDEFGHIJKLMNOPQRSTUVWXYZ => GWOLEBIJAHVMFQCSPXUYNTKZRD {a different mapping but still of the same kind}.
I believe {I cannot think of, but would love to see, a counterexample} this can be generalised to any set of simple one-to-one mappings where the sets of permitted values at the input and output are equivalent: Km(Km-1(.....K2(K1(x)).....)) == Kn(x).
Money spent on imported, proprietary software is effectively lost for all time. The scrap value of proprietary software is limited to a few kilos of paper for pulp, and some CDs for
Nothing - provided you are using the latest version. It's fast, it looks good, it supports CSS (even passing ACID2), it has tabs, it accepts Mozilla-style extensions. In fact, it does everything Opera does -- but, unlike Opera, you get the source code.
..... except IE .....
Konqueror 2.X was a poor imitation of Internet Explorer (without the vulnerabilities). But things have moved on a lot since those days
By the time MS release Office for Linux, there may well be a decent unCC implementation.
Now, that's going to make a difference.
Microsoft tolerated piracy because they knew damn well it was hurting smaller companies more than it was hurting Microsoft. Selling an office suite for a tenth of the "official" asking price of MS Office is irrelevant if the "street" price of MS Office is £nil. Basic human nature -- specifically, the hunter-gatherer instinct, a remnant from caveman times which lives on in us today and explains why some people think paying full price is cheating, why some people will consider a pair of shoes a great bargain even if they do not fit and why your dog prefers food stolen from someone else's plate -- suggests that the more expensive product will get pirated and the less expensive product will get ignored. If MS Office had not been so easy to pirate, then less expensive, competing products would have gained a greater market share.
MS would rather you were using pirated Microsoft software than Open Source -- after all, if you're using pirated MS software, there's at least a small chance that you can be strong-armed into buying legitimate MS software {the other way to get legal would be to go Open Source, which has happened but is admittedly a rare occurrence}. Whereas, there's no reason why anyone who is already happy with Open Source would want to change to Microsoft.
I thought MS Office included an almost-complete OS and filesystem API anyway, to compensate for various brokennesses in Windows -- Office certainly seems to have its own file requester code, though it's only obvious when you install a new Office on top of an older Windows.
.doc format. I have high hopes for the next KOffice.
Anyway, if MS Office ever starts supporting ODF, then expect significant advances in Open Source office suites -- the developers will finally be able to do other things beside reverse-engineer the latest
You will find, if you place scales under each wheel, and measure the surface area of each tyre which is in contact with the scales and the pressure in each tyre, that the tyre pressure in Pascals will be equal to the mass showing on the scales in kg., times g, divided by the area of contact in square metres.
I had always thought the addicting property of opiates was integral with the pain-relieving property. As I understand it it, it works something like this:
Morphine {and that includes derivatives such as heroin} basically binds to the same receptors as endorphins, the body's natural pain-relievers {and feelgood chemicals: a dose of endorphins is your body's usual reward for behaviour deemed to be of evolutionary benefit}. Your body produces extra endorphins in times of trauma; but there is usually some level of endorphins in your system, keeping you from feeling the ends of your bones scraping against one another or the pressure of the blood in your arteries. Some people -- especially kids -- deliberately inflict pain on themselves to crank up their endorphin production.
Introducing artificial substances interferes with the body's self-regulatory systems, leading to less endorphin production. Therefore, when you come down off morphine / heroin / methadone, your background endorphin level is lower than it should be -- and as a consequence, you begin to feel the sensations of your body working normally -- which would normally be masked by endorphins -- as pain. Your joints are painful, the movement of food through your digestive system {which has just started up again} is painful, your blood flow is painful, the increasing pressure in your bladder is painful.
Most people can't wait long enough for their endorphin production to get back to normal levels, and instead take another dose just to get rid of the pain of existence. This, of course, is liable to undo the work of restarting endorphin production -- and that is why morphine is addictive.
So how does this new stuff work? If it's got a similar enough structure to morphine that it binds to endorphin receptors, then surely it will slow or block endorphin production just as much as any other flavour of junk? The only way I can see it possibly working is if its pain-relieving property wears off at exactly the same rate that the body naturally begins producing endorphins from scratch. But isn't that a person-to-person variable?
Yeah, and by measuring the distance between molten chunks of chocolate in a microwave oven, you're actually measuring the speed of uwaves, not the speed of light.
Hint: go read some physics.
Let's suppose the air in the car's tyres is at 200 000 Pa, and the car weighs 1000kg, and for simplicity we'll assume g=10 ms-2. (If you're going to do proper science, you might as well use proper measuring units.) Now the weight of the car is 10000 Newtons and the only thing supporting it is the air in the tyres. So, since every action has an equal and opposite reaction, you must have 10 000 Newtons pressing upwards on the car through the air in the tyres. And since the pressure in a fluid acts equally in all directions, you have 10 000 Newtons pressing down on the road through the air in the tyres. We know the pressure of the air in the tyres is 200 000 Pa, so the area in contact with the road must be 10 000 / 200 000 = 10 / 200 = 0.05 m2. If we multiply that by 10000 we get 500cm2, or 125cm2 per tyre, which is not unreasonable.
Try it with figures for your own vehicle.
What they are measuring in kilogrammes is really their mass {which is a property of an object which relates to how much matter it contains, and is measured in kilogrammes}, not their weight {which is a force exerted by an object due to gravitational attraction, and is directly dependent upon its mass, and is measured in Newtons}.
At least, if they were using a beam balance, they would really be measuring their mass {assuming that the value of g is the same for the person being weighed and the counterweight[s]}. If they were using a spring balance, then they would actually be measuring their weight {in Newtons} and dividing it by some assumed value for g to convert it to an approximate mass. g is about 10 ms-2 over most of the Earth's surface; and not too far off pi ** 2 for that matter, which is handy sometimes for quick pendulum calculations: T = As Near As Damn Is To Swearing 2 * sqrt(l).