You can prove that a program halts, or doesn't, provided that you understand the program, and in particular the invariants that will determine it to halt. You just cannot write a program that will answer the question on an arbitrary other program. Typically you will design the proof as you design the program. That is the point made in Disjkstra's "A Discipline of Programming" essay (published in the 70s). This kind of things has been forgotten since then and hackers have since built the software ecosystems as a piling of shoddy abstractions, each more complicated to deal with the errors and indeterminism of the previous one.
You're not expected to model the full behavior of your program. Model checking is useful for testing individual properties such as bounds on ressource allocation, non-deadlock of thread synchronization, or security-related invariants.
I hope this will help push the use of formal methods, particularly in software development. There is no way that software development can be carried out in the massively distributed / multi-core era using the test-and-tweak, black magic approach that has so far dominated software creation and that has led to the big mess that we are in.
Bridges are here to allow people to travel, and people pay taxes. Tens of thousands of people spend comfortable incomes in Washington and lots of sales tax on their spending thanks to Microsoft, that should be enough to keep the infrastructures that support these people.
So according to this review, the book spends most of its time on three things : (1) expression general judgements about the overall quality of Windows Vista (2) explaining simple, generic computer notions to the clueless out there (3) Describing annoyances of Windows operation systems that have been out there, along with their workarounds, in many of the previous versions of Windows.
So where is the part that says why you shouldn't upgrade to Vista ?
It is a stupid law, like many laws that in France are stupid. There are laws in France that forbid in general for a retailer to sell any merchandise for less than the invoice price, that is, with a negative markup, unless in controlled conditions during two periods in the year ("les soldes"). This is supposedly to prevent big retail groups from pricing out of business artisan boutiques.
But the book laws are special in that the price of new books is supposed to be completely determined by the publisher. The retailer can only give a 5% discount on new releases ( 1 yr old). Also retailers are at an obligation to order any title that they don't have in stock and that is requested by a customer at no additional cost. In the pre-eRetail era the rationale was that it guaranteed that wherever you were and wherever you shopped you had the same access to literature, knowledge, culture, information, whatever. Retailers could not "control" what you were reading by dumping certain titles and withholding others. Nowadays it's mostly obsolete obviously.
The actual hardware is not what Microsoft is after with the Surface, but rather the software, development platform and user experience. For all of these prototypes that explore various ways of bringing the image to any big flat surface and to track the user's touch, all of them show you how to use google maps, and then their ad-hoc photo shuffling application, and that's all. None of them has yet any real useful application or complete SDK with hardware support abstracted.
I have sympathy for the HD-DVD format, for reasons like their blood lineage with the DVD Forum, their forsaking of Region Coding, the availability of a hybrid DVD format, the general emphasis on drive prices as cheap as possible (most people now have at least two TVs on which they expect to watch DVDs, better buying two $140 drives than two $400 drives). I don't think that consummers would stand to benefit from a format victory decided by studio executives. The best outcome in my opinion would have been co-existence. The cost of publishing movies in two different formats is very small to studios. Look at the game industry, which is thriving while having so many multi-platform games ! Mastering both Blu and HD discs is very cheap in comparison, especially using the same codec in both cases ! There is the shelf space issue but it's becoming obsolete as brick and mortar retail and rental places are vanishing. And there will be co-existence anyway, with several VOD platforms, which will be much more complicated. Would studios also exclusively supports iTunes over Amazon Unbox or Live Marketplace ?
I think the way this format war will end up is being the last nail in the coffin of physical media distribution, and that's too bad. I myself cannot shake out the need to _own_ movies and line them up on a shelf for me to browse. I must be old...
That makes them hardly more expensive than a high end upconverting DVD player, which they also are. And if HD-DVD really will go away, then hundreds of title will end up in bargain bins and be offered for next to nothing on peer-to-peer second hand markets. Just that would be enough to keep us busy and see if physical media will be replaced or not by on demand in the next couple of years. On that account, maybe it's the $400-$500 investment in a Blu Ray player that doesn't make sense.
How to recognize someone who would give good advice about how to recognize a good programmer ? I think the C.V. can be misleading : the " official " experience at hiring programmers does not necessarily mean the the person would be apt at giving good advice about hiring programmers.
FYI, no programming language compiler (except maybe ADA) has ever fully complied to any particular version of any international standard of any programming language. Programming language standards are just a convenient way to document what a compiler does : say it's a C++ compiler, it compiles the C++ standard, already written, to which you add your own delta, which can usually be written up more concisely. Or a guide to new implementation. Or a guide to draft programs that will be relatively easily portable across platforms.
Microsoft just has a past history of being a little bit more officially disdainful of the standard, in particular C++90, claiming that compliance was not a feature asked for by their users, of which there are a lot. Technically it's true. But look at C# : not only did they do a very open standard unlike Java, but also an elegant and concise one at that. And very closely implemented by their own compilers of course...
A given individual will put value both on the fact that certain people see the material that you put about yourself online, and you also put value on the fact that certain other people are not allowed to see that material. The most simple example is the work life/private life separation, but in general many people see themselves as different personnalities (family life, social life, hobby life, professional life, love life) that are only overlapping in a carefully controlled manner. If there would be only one dominant social network, that would be impossible.
There's not going to be a clear winner : several social networking websites will co-exist, because the value of a network depends both of who's in it and who's not.
Google is a great company filled with brilliant people like maybe no company has ever been. But there's something I never understood about it : how do they actually plan to lock in their position ?
They do many things very well, but I don't see any of their major services from which you cannot switch to a competitor on a whim. Let's be honest : for 99% of searches, several other search engines will give you results that are at least as relevant or useful as Google's. Even if objectively you would find any google service to be slightly superior than its counterpart, there really is barely any friction from switching if you don't like their name anymore or if you feel like giving a chance to a competitor. They don't even have any notable "network effect" assets like eBay, Paypal, Facebook, Amazon Marketplace and recommendations, the IMDB, etc.
For me, the price of a book is essentially $4. This is $3.99 shipping plus the symbolic $.01 that most used-book dealers charge as the nominal price for used books sold on Amazon (hardcover or paperback, the same). Dealers get their profit from the difference between the shipping compensation that they get on the sale from Amazon and the actual cost of shipping the book. There are more expensive books on Amazon marketplace of course (textbook, non-obsolete computer books,...), but these aren't going to be available from $10 on Kindle are they ? If books on Kindle were $5 for novels and about $15 for "useful" titles, that would seem more fair to me, given that the publisher does away with printing, logistics and the possibility that the book will be read by more than one person (in a library, borrowed by a friend or re-sold as a used book).
This, or the device should be at an aggressively subsidized price, made up from sales of content.
I like the device, and love the business model independently of the price point though.
Parent is indeed funny, and should also be moderated as insightful for pointing out the idiocy of the syntax for assignment that has been the mainstream one since the C language.
Maybe the reason why it's not done at Google to ostensibly check the stock price every day is out of embarassment over the fact that employees that join now will have to hope that their $700 options stay afloat while they may be more brilliant and their contribution more critical to the company than that of employees who join only one year ago.
I think that options are great for startup companies, which Google is not anymore, to compensate for the risk that the people who work in them do, and the fact that the contribution of early employees is by definition seminal to building a successful company. But for mature companies (which Google is now), it becomes too difficult to manage as a standard compensation system. How can you keep employees focused on their commitments if the cash bonus that you can afford to offer them at their annual review is dwarfed by the value of the stock options they already got just for being hired ?
I was taking Indy 4 as an extreme example. It does look pretty likely that in that case, they could actually raise $1bn sight unseen. But again, it's very, very extreme. The next album of a huge worldwide band like Radiohead could make that work easily too.
Here is a model to consider for IP compensation : some artist/programmer/writer/etc has an album/application/novel/etc and a way to convince the world it is worth having. For example, an band could use its already acquiered fame, like Radiohead has. Or Spielberg's producers could do that with Indiana Jones IV. Then they put up a web site and say that they will release the thing in the public domain, right there, in all of the lossless, high def, full featured formats that can be imagined, for anybody to download, share, burn , enjoy, copy, modify, etc. But only after some Paypal account has reached a certain level. Spielberg says okay Indy IV is in the public domain, 4K lossless file, mpeg 4 encodes and everything for your convenience, as soon as $1bn has been credited to this account. That would amount to 100 million households around the world figuring out that $10 is less than they would have paid to see the thing in theaters AND buy the DVDs. Sounds feasable. Unknown artists could put their stuff for free at first until they acquire some fans and set some ransoms.
There should be some equivalent to the http://en.wikipedia.org/wiki/Godwin's_Law for arguing that the US is a less densely populated country when faced with the fact that such and such service or infrastructure in the US is inferior to its counterparts in other industrialized countries.
Slashdot Mirror
You can prove that a program halts, or doesn't, provided that you understand the program, and in particular the invariants that will determine it to halt. You just cannot write a program that will answer the question on an arbitrary other program. Typically you will design the proof as you design the program. That is the point made in Disjkstra's "A Discipline of Programming" essay (published in the 70s). This kind of things has been forgotten since then and hackers have since built the software ecosystems as a piling of shoddy abstractions, each more complicated to deal with the errors and indeterminism of the previous one.
You're not expected to model the full behavior of your program. Model checking is useful for testing individual properties such as bounds on ressource allocation, non-deadlock of thread synchronization, or security-related invariants.
I hope this will help push the use of formal methods, particularly in software development. There is no way that software development can be carried out in the massively distributed / multi-core era using the test-and-tweak, black magic approach that has so far dominated software creation and that has led to the big mess that we are in.
Bridges are here to allow people to travel, and people pay taxes. Tens of thousands of people spend comfortable incomes in Washington and lots of sales tax on their spending thanks to Microsoft, that should be enough to keep the infrastructures that support these people.
Finally, using a point-and-click interface will resemble using VI. The beard-suspender set rejoice !
So according to this review, the book spends most of its time on three things : (1) expression general judgements about the overall quality of Windows Vista (2) explaining simple, generic computer notions to the clueless out there (3) Describing annoyances of Windows operation systems that have been out there, along with their workarounds, in many of the previous versions of Windows.
So where is the part that says why you shouldn't upgrade to Vista ?
MSFT shares are up 3% today after another strong rise yesterday, after announcing their financial results and outlook.
It is a stupid law, like many laws that in France are stupid. There are laws in France that forbid in general for a retailer to sell any merchandise for less than the invoice price, that is, with a negative markup, unless in controlled conditions during two periods in the year ("les soldes"). This is supposedly to prevent big retail groups from pricing out of business artisan boutiques.
But the book laws are special in that the price of new books is supposed to be completely determined by the publisher. The retailer can only give a 5% discount on new releases ( 1 yr old). Also retailers are at an obligation to order any title that they don't have in stock and that is requested by a customer at no additional cost. In the pre-eRetail era the rationale was that it guaranteed that wherever you were and wherever you shopped you had the same access to literature, knowledge, culture, information, whatever. Retailers could not "control" what you were reading by dumping certain titles and withholding others. Nowadays it's mostly obsolete obviously.
The actual hardware is not what Microsoft is after with the Surface, but rather the software, development platform and user experience. For all of these prototypes that explore various ways of bringing the image to any big flat surface and to track the user's touch, all of them show you how to use google maps, and then their ad-hoc photo shuffling application, and that's all. None of them has yet any real useful application or complete SDK with hardware support abstracted.
I have sympathy for the HD-DVD format, for reasons like their blood lineage with the DVD Forum, their forsaking of Region Coding, the availability of a hybrid DVD format, the general emphasis on drive prices as cheap as possible (most people now have at least two TVs on which they expect to watch DVDs, better buying two $140 drives than two $400 drives). I don't think that consummers would stand to benefit from a format victory decided by studio executives. The best outcome in my opinion would have been co-existence. The cost of publishing movies in two different formats is very small to studios. Look at the game industry, which is thriving while having so many multi-platform games ! Mastering both Blu and HD discs is very cheap in comparison, especially using the same codec in both cases ! There is the shelf space issue but it's becoming obsolete as brick and mortar retail and rental places are vanishing. And there will be co-existence anyway, with several VOD platforms, which will be much more complicated. Would studios also exclusively supports iTunes over Amazon Unbox or Live Marketplace ?
I think the way this format war will end up is being the last nail in the coffin of physical media distribution, and that's too bad. I myself cannot shake out the need to _own_ movies and line them up on a shelf for me to browse. I must be old...
Never underestimate how irrelevant it is for a grad schooler, that their Disney direct-to-video sequel is in HD or not.
That makes them hardly more expensive than a high end upconverting DVD player, which they also are. And if HD-DVD really will go away, then hundreds of title will end up in bargain bins and be offered for next to nothing on peer-to-peer second hand markets. Just that would be enough to keep us busy and see if physical media will be replaced or not by on demand in the next couple of years. On that account, maybe it's the $400-$500 investment in a Blu Ray player that doesn't make sense.
How to recognize someone who would give good advice about how to recognize a good programmer ? I think the C.V. can be misleading : the " official " experience at hiring programmers does not necessarily mean the the person would be apt at giving good advice about hiring programmers.
Nice hack but that's pretty much how some existing surface computing devices work anyway. That a mass produced device is cheaper is nothing new.
FYI, no programming language compiler (except maybe ADA) has ever fully complied to any particular version of any international standard of any programming language. Programming language standards are just a convenient way to document what a compiler does : say it's a C++ compiler, it compiles the C++ standard, already written, to which you add your own delta, which can usually be written up more concisely. Or a guide to new implementation. Or a guide to draft programs that will be relatively easily portable across platforms.
Microsoft just has a past history of being a little bit more officially disdainful of the standard, in particular C++90, claiming that compliance was not a feature asked for by their users, of which there are a lot. Technically it's true. But look at C# : not only did they do a very open standard unlike Java, but also an elegant and concise one at that. And very closely implemented by their own compilers of course...
A given individual will put value both on the fact that certain people see the material that you put about yourself online, and you also put value on the fact that certain other people are not allowed to see that material. The most simple example is the work life/private life separation, but in general many people see themselves as different personnalities (family life, social life, hobby life, professional life, love life) that are only overlapping in a carefully controlled manner. If there would be only one dominant social network, that would be impossible.
There's not going to be a clear winner : several social networking websites will co-exist, because the value of a network depends both of who's in it and who's not.
Google is a great company filled with brilliant people like maybe no company has ever been. But there's something I never understood about it : how do they actually plan to lock in their position ?
They do many things very well, but I don't see any of their major services from which you cannot switch to a competitor on a whim. Let's be honest : for 99% of searches, several other search engines will give you results that are at least as relevant or useful as Google's. Even if objectively you would find any google service to be slightly superior than its counterpart, there really is barely any friction from switching if you don't like their name anymore or if you feel like giving a chance to a competitor. They don't even have any notable "network effect" assets like eBay, Paypal, Facebook, Amazon Marketplace and recommendations, the IMDB, etc.
For me, the price of a book is essentially $4. This is $3.99 shipping plus the symbolic $.01 that most used-book dealers charge as the nominal price for used books sold on Amazon (hardcover or paperback, the same). Dealers get their profit from the difference between the shipping compensation that they get on the sale from Amazon and the actual cost of shipping the book. There are more expensive books on Amazon marketplace of course (textbook, non-obsolete computer books, ...), but these aren't going to be available from $10 on Kindle are they ? If books on Kindle were $5 for novels and about $15 for "useful" titles, that would seem more fair to me, given that the publisher does away with printing, logistics and the possibility that the book will be read by more than one person (in a library, borrowed by a friend or re-sold as a used book).
This, or the device should be at an aggressively subsidized price, made up from sales of content.
I like the device, and love the business model independently of the price point though.
Parent is indeed funny, and should also be moderated as insightful for pointing out the idiocy of the syntax for assignment that has been the mainstream one since the C language.
Maybe the reason why it's not done at Google to ostensibly check the stock price every day is out of embarassment over the fact that employees that join now will have to hope that their $700 options stay afloat while they may be more brilliant and their contribution more critical to the company than that of employees who join only one year ago.
I think that options are great for startup companies, which Google is not anymore, to compensate for the risk that the people who work in them do, and the fact that the contribution of early employees is by definition seminal to building a successful company. But for mature companies (which Google is now), it becomes too difficult to manage as a standard compensation system. How can you keep employees focused on their commitments if the cash bonus that you can afford to offer them at their annual review is dwarfed by the value of the stock options they already got just for being hired ?
I was taking Indy 4 as an extreme example. It does look pretty likely that in that case, they could actually raise $1bn sight unseen. But again, it's very, very extreme. The next album of a huge worldwide band like Radiohead could make that work easily too.
Here is a model to consider for IP compensation : some artist/programmer/writer/etc has an album/application/novel/etc and a way to convince the world it is worth having. For example, an band could use its already acquiered fame, like Radiohead has. Or Spielberg's producers could do that with Indiana Jones IV. Then they put up a web site and say that they will release the thing in the public domain, right there, in all of the lossless, high def, full featured formats that can be imagined, for anybody to download, share, burn , enjoy, copy, modify, etc. But only after some Paypal account has reached a certain level. Spielberg says okay Indy IV is in the public domain, 4K lossless file, mpeg 4 encodes and everything for your convenience, as soon as $1bn has been credited to this account. That would amount to 100 million households around the world figuring out that $10 is less than they would have paid to see the thing in theaters AND buy the DVDs. Sounds feasable.
Unknown artists could put their stuff for free at first until they acquire some fans and set some ransoms.
And, you know, " the pen is mightier than the sword. "
There should be some equivalent to the http://en.wikipedia.org/wiki/Godwin's_Law for arguing that the US is a less densely populated country when faced with the fact that such and such service or infrastructure in the US is inferior to its counterparts in other industrialized countries.