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I teach physics. One classic use of computers in physics education is to help students check answers to their homework problems. Before computers, this was done by giving the answers to odd-numbered problems in the back of the book. Computerized answer checking can be superior to that in a couple of ways. With problems that have a numerical answer, many students tend to start from the answer in the back of the book, and then try to work backwards to figure out how they could get that answer; the result is that they don't learn how to solve problems from first principles. Some of them will just write a bunch of wrong stuff on their paper, and then append the answer to it as if that was the answer they found :-) With problems that have a symbolic answer (e.g., x=mv^2/2F is the answer to the problem), the same problem gets even worse. Assigning problems with symbolic answers is very important IMO, because we're trying to instill good problem-solving habits, which means solving problems algebraically, and only plugging in numbers at the very end. Also, it can teach them how to interpret an algebraic result, which is something most of them have never done. Another advantage of doing answer checking on the computer is that I can require my students to use the answer checker if they want to get credit, and tell them that if the computer gives them the feedback saying that their answer is wrong, and they can't figure out how to fix it, they should come to my office hours to get help. This is very different from the usual ethos, which is to turn in a paper with lots of wrong answers and whine for partial credit. The system I use is an open-source one I wrote, called Spotter; its web page has links to a bunch of other free-as-in-something software that does similar things.

Eric Mazur's book Peer Instruction is worth checking out if you're teaching physics. He's a physic prof at Harvard who pioneered the technique of giving students multiple-choice questions to ponder, polling them, and then if there isn't a clear consensus for the right answer, having them discuss it in groups. I think he originally implemented it with cardboard cards, but most people these days to it using the electronic clickers. Personally, I tried the technique and wasn't that happy with it, but it still helped me to get outside the box of straight lecturing. It seems to be mainly a technique that's useful in huge lecture classes, which isn't what I teach at a community college, and isn't what the OP teaches in high school. I've also heard a lot of students complain bitterly about the clickers -- partly about the cost (which I think is a valid complaint) and partly about nontraditional instruction (which I think just indicates that they're conservative and reluctant to take responsibility).

There are lots of free college and high school textbooks out there, and you should consider using them. See my sig for a catalog of free books that you can search for math and physics books.

Some free-as-in-something possibilities that either run on linux or are web-based:

• YourSky - This is a very elaborate and sophisticated web-based service that makes star charts; free as in beer, but not open-source
• PlanetFinder - A java applet I wrote that concentrates on ease of use; good for figuring out what you're seeing with your naked eyes, or for planning observations, e.g., when is Mars going to rise so I can point my telescope at it?
• Stellarium - cool photorealistic planetarium (computer-generated images, as opposed to maps or photos); FOSS
• Celestia - lets you fly around the universe in 3d; FOSS
• Xephem - Sky maps. Free as in beer. Has some really nasty licensing issues. I used to use it a lot, and it worked great, but it's no longer available as a Debian package.

Note that they all do different things. They're not interchangeable.

I have some experience with trying to verify people's academic affiliations via the internet. I've made some physics textbooks I wrote available for free on the web. I also distribute the instructors' materials (homework solutions, exam files, etc.) for free via the web, but they're encrypted, so professors need to contact me to get the key. My policy is here. Basically I use a policy like the one described in the slashdot summary: they have to be able to show me their e-mail address on their school's web page.

Well, it kinda sorta works, but not always.

1. Not all experts have an EDU address. The version of this that I most often see is that they're homeschoolers. In that case, I just say I'm sorry, but I'm not going to give them the materials. For wikipedia, the more likely issue would be that they're experts with PhDs, but they just aren't working in academia.
2. Many experts with institutional addresses can't or won't get their employer involved in authenticating them This isn't necessary. As long as their school has a faculty directory with e-mail addresses listed, the school doesn't have to do anything special.
3. "Underground experts" such as black-hat security experts value their anonymity greatly. As I understand the proposal, nobody is saying you won't be able to edit WP or citizendium unless you have a PhD that's verifiable by this method. They're just saying that if you want to be able to throw your weight around and claim to have a PhD, this is the proof you'd have to provide.
4. The same goes for political dissidents who have expertise to share under a pseudonym. Same as #3.

I am somewhat sympathetic to people who aren't able to meet my requirements for various reasons, and for that reason I sometimes show some flexibility. Actually I myself would just barely be able to meet them. If you look at the staff directory for my department at my school, you'll see that my address is listed, but is heavily spam-armored, and isn't the .edu e-mail address my school provided me. This is because (a) I'm trying to avoid spam, (b) my school's e-mail sucks, and (c) I hate getting occupational spam (e.g., people sending out a broadcast e-mail to 1000 faculty and staff to say that their kid is selling girl scout cookies). A common issue I've run into is that the school hires a part-timer to teach the course, and gives the part-timer authority to choose the textbook he wants. He chooses mine, but isn't listed on the department directory because he's part time. In that situation, I bend my own rules as long as he seems legit. Another issue is that although my books are college textbooks, I do have quite a few high school teachers using my books, and often their school doesn't have any web site at all, or has a very rudimentary one without a staff listing.

Unfortunately, every feature they currently offer can be coded internally rather easily (my school proves this quite well)
I'm the author of an open-source course management package called Spotter, and I have to agree -- both the ideas behind and the implementation of one of these things are pretty trivial. My own software is more narrowly focused on science classes, and doesn't have some of the broader functionality in it that Blackboard has, but it still does enough that it seems to do every single thing listed in Blackboard's ridiculous patent. Really the only thing about mine, conceptually, that I would claim was non-obvious was a method for checking symbolic math answers using numerical sampling and continuation of analytic functions into the complex plane -- maybe I should patent that :-) These systems have been around for a long time, and all the ideas have been in the air. The system I wrote was actually inspired by a demo I saw of an open-source system called lon-capa, developed at MSU; lon-capa has been around, in one form or another, since 1992, whereas Blackboard and WebCT only date back to about 1995. I'm sure the reason none of the academics who developed the OSS systems filed patents is that they realized how ridiculously trivial the ideas were. Blackboard has clearly realized that they can't compete on price or features, because systems like these are easy to implement for free. So instead they've decided to create an artificial monopoly for themselves by suing anyone who tries to compete. Gosh, isn't it generous of them to make a pledge (with strings attached) not to sue me. I'd also appreciate it if they'd make a pledge not to burn down my house.

Conversion of heat into any other type of energy achieves it's maximum at 33% (the other 66% heats up the environment, according to the Laws of Thermodynamics).
No, the maximum efficiency for a heat engine is given by 1-T(low)/T(high) (absolute temperatures), which can be higher than 33%. If you can make T(high) high enough, and T(low) low enough, you can get 99% efficiency, or 99.9% efficiency, or whatever you like.

Arguably, these laws have not been proven, and they can't ever be proven. But they have been unchanged for quite some time now.
No, actually they have been proved, mathematically, within their realm of applicability, and to within the level of statistical certainty that's inherent in them (which is not an issue for a macroscopic device).

A breakthrough like this would not go unnoticed and thanks to my thermodynamics professor I would be the first one to hear about it (he's a nut about engines). So I think that part of the article is something someone tried to spike in to give the engine more of a wow-factor
No, the problem is just that you don't understand thermodynamics.

Here is an open-source planetarium applet I wrote. It can be convenient because you can just bookmark it in your browser, and you don't need to click around. In most cases, it does a pretty good job of guessing your location based on your language and timezone, e.g., since my language is English and my timezone is PST, it guesses I'm in Los Angeles, which is correct. Even if you were in, say, San Francisco, it would still be roughly correct.

Here is a viewing guide I wrote for binocular astronomy. Doing astronomy with binoculars can be a lot of fun. It lets you see a lot of stuff you can't see with the naked eye, and there are a lot of objects for which it's also superior to a telescope, because of their large angular sizes, which don't fit into a telescope's field of view. For anyone thinking of getting a telescope, a good first step is to spend a few months or a year doing binocular observing, because it builds up your skills, and you're less likely to be frustrated when you try a telescope.

Here is an open-source planetarium applet I wrote. It can be convenient because you can just bookmark it in your browser, and you don't need to click around. In most cases, it does a pretty good job of guessing your location based on your language and timezone, e.g., since my language is English and my timezone is PST, it guesses I'm in Los Angeles, which is correct. Even if you were in, say, San Francisco, it would still be roughly correct.

Here is a viewing guide I wrote for binocular astronomy. Doing astronomy with binoculars can be a lot of fun. It lets you see a lot of stuff you can't see with the naked eye, and there are a lot of objects for which it's also superior to a telescope, because of their large angular sizes, which don't fit into a telescope's field of view. For anyone thinking of getting a telescope, a good first step is to spend a few months or a year doing binocular observing, because it builds up your skills, and you're less likely to be frustrated when you try a telescope.

I have a hard time understanding why I hear so many people complaining about JS as a language. I think a lot of Java programmers don't like it because it's not Java (not strongly typed, ...), and a lot of C++ programmers don't like it because it's not C++.

The truth is that you can do some pretty amazing stuff with JavaScript. My favorite demo is here. It's a web-based calculator, and if your browser has MathML set up correctly, it'll display your equation on the fly, as you type it, in standard math notation. For instance, if you type 1/(2+pi), it displays a fraction bar, with 1 on top, and 2+pi on the bottom (pi rendered as a Greek letter). (I think recent versions of Firefox have MathML and its fonts set up correctly by default, but if not, you can download the necessary fonts (instructions). For IE, you need to install MathPlayer.) What I think this calculator app demonstrates pretty dramatically is how powerful a development platform the web browser can be, without messing with the ugliness of AJAX at all. WYSIWYG mathematics typesetting is the kind of application that people used to pay $100 for ca. 1995, and now it's not only free, it's open-source, and it's an app that you can just run in your browser, without having to install anything.

According to the laws of thermodynamics, the conversion of heat to other forms of energy requires access to thermal reservoirs at two different temperatures, and there's a limit on the possible efficiency of the process, which is 1-T(low)/T(high). Their press release doesn't seem to be claiming anything that violates this, so it's not obviously voodoo science or anything. However, any such heat engine is only going to be useful when (a) you have cheap access to hot and cold reservoirs, (b) the temperature difference is fairly high, and (c) the efficiency of the heat engine is superior to the other practical heat engines that you have to choose from, or there's some other practical reason why this particular heat engine is better for your application.

The reason nobody has heard of it is probably the evil college bookstore cartel.
I think it's a bit of a stretch to blame college bookstores for this. They're mostly nonprofit. It's the publishers who are really being evil.

They will break your hands with hammers if they find out you have been using free textbooks instead of the ones they sell.
I'm currently typing this with two unbroken hands, after 9 years of using free textbooks in my physics classes.

There are already hundreds of free college textbooks on the web:

• theassayer.org (a catalog of free books in general, not just textbooks; accepts user-submitted reviews)
• textbookrevolution.org (a site specifically devoted to free textbooks)
• libertytextbooks.org (a selection of high-quality free textbooks)

Wikibooks was originally envisioned as a project that would have textbooks as its main raison d'etre, but IMO it's failed at that goal. Although there are quite a few textbooks at the wikibooks site, almost none of them are of high enough quality to be widely adopted for classroom use. I don't think that's particularly surprising, because the wiki method is simply unsuited to the task of writing textbooks. The killer app for wikibooks right now seems to be books about video games.

The reason nobody has heard of it is probably the evil college bookstore cartel.
I think it's a bit of a stretch to blame college bookstores for this. They're mostly nonprofit. It's the publishers who are really being evil.

They will break your hands with hammers if they find out you have been using free textbooks instead of the ones they sell.
I'm currently typing this with two unbroken hands, after 9 years of using free textbooks in my physics classes.

There are already hundreds of free college textbooks on the web:

• theassayer.org (a catalog of free books in general, not just textbooks; accepts user-submitted reviews)
• textbookrevolution.org (a site specifically devoted to free textbooks)
• libertytextbooks.org (a selection of high-quality free textbooks)

Wikibooks was originally envisioned as a project that would have textbooks as its main raison d'etre, but IMO it's failed at that goal. Although there are quite a few textbooks at the wikibooks site, almost none of them are of high enough quality to be widely adopted for classroom use. I don't think that's particularly surprising, because the wiki method is simply unsuited to the task of writing textbooks. The killer app for wikibooks right now seems to be books about video games.

Free collaborative wiki style textbooks for the third world would be great. There are also already a few free textbooks available available on the Internet such as these:

• Discover Physics
• The Modern Revolution in Physics
• Newtonian Physics
• Lessons In Electric Circuits Volumes I - VI
• A First Course in Linear Algebra
• First Year Calculus

Perhaps we ultimately could end up with some textbooks done collaborative Wiki style and other free text books done in a different way. Either way I think free textbooks would be great especially for common slow changing subjects such algebra, calculus, English, history and such.

Free collaborative wiki style textbooks for the third world would be great. There are also already a few free textbooks available available on the Internet such as these:

• Discover Physics
• The Modern Revolution in Physics
• Newtonian Physics
• Lessons In Electric Circuits Volumes I - VI
• A First Course in Linear Algebra
• First Year Calculus

Perhaps we ultimately could end up with some textbooks done collaborative Wiki style and other free text books done in a different way. Either way I think free textbooks would be great especially for common slow changing subjects such algebra, calculus, English, history and such.

Free collaborative wiki style textbooks for the third world would be great. There are also already a few free textbooks available available on the Internet such as these:

• Discover Physics
• The Modern Revolution in Physics
• Newtonian Physics
• Lessons In Electric Circuits Volumes I - VI
• A First Course in Linear Algebra
• First Year Calculus

Perhaps we ultimately could end up with some textbooks done collaborative Wiki style and other free text books done in a different way. Either way I think free textbooks would be great especially for common slow changing subjects such algebra, calculus, English, history and such.

About a year ago, I switched my open-source grade-recording app for teachers from using SHA1 for digital watermarking to using Whirlpool. The good news is that my users should gradually be upgrading, and new users will already be using the new, more secure version. The bad news is that it now depends on the Perl Digest::Whirlpool library, which is on CPAN, but hasn't been packaged by any distros that I know of. Because of that, it's a lot harder for the average user to install than it used to be.

Haven't used Scribus, but pdftex is very solid, and has worked great for me, although there is admittedly a very steep learning curve if you need to write your own class file for a complicated book -- mine is 1400 lines.

One interesting thing about the physics of solar sails is that, counterintuitively, the worst possible thing to do with one is turn it perpendicular to the sun's rays. You actually get the maximum rate of transfer of kinetic energy if the sail is at 55 degrees to the rays, rather than 90 (explanation here, p. 149). There are also some pretty counterintuitive physical results about ordinary water sailing, e.g., that it's possible for some racing sailboats to complete a closed-loop course at an average speed greater than the speed of the wind!

Watermarking can be used for good or for evil. For instance, this book has a watermark at the bottom of every page explaining that the book is CC licensed, and available for free from a certain URL. I did this because someone had taken the pdf file, carefully removed the copyright page and licensing information, and was selling the book on a CD on ebay :-) It was ironic, because he could have *legally* sold it for free according to the license, but he wanted to mislead his customers so that they wouldn't know they could get it for free off of a web page rather than buying from him. Of course, it wouldn't be all that difficult to remove the watermark, but because it's on every page, it would be *more* work to do that than it was for the guy just to remove the copyright page. Similarly, I don't think any DRM scheme for music will ever be able to stand up against a determined attack, but they can make it enough of a hassle that it will cut down on illegal copying. Whether you think that's good or bad probably depends on whether you're a college student or a music industry executive...

It's too bad that xephem has licensing problems, and has been dropped from Debian.

Browsing through wikibooks, wikipedia's sister project to try to write other books the wiki way, it's generally pretty difficult to find anything good, even though wikibooks is 2.5 years old. I recently did an unscientific study as part of my research for an article on free books, and the Blender books on wikibooks were one of the very few success stories out of the massive piles of junk there. However, a lot of the best content on wikibooks seems to be stuff that was more or less just dumped into wikibooks after having already been written elsewhere, and comparing the wikibooks stuff on Blender with the stuff on the Blender site, it looks like that may actually have been the case here. There's nothing wrong with that per se (WP has a lot of 1911 Britannica articles that were just copied over), but it doesn't exactly help to convince me that the wiki book model has much potential for success outside of WP, which is uniquely well suited to the wiki approach.

For me, the real problems come when I'm debugging a Perl program that's linked to someone else's C library. I have an app that had been stable for a long time, until I found that with recent releases of Perl/Tk it suddenly started crashing once a week or so. A stack trace shows that it's crashing inside a certain C function in Perl/Tk, but my lack of C skills have stopped me from getting to the point where I could file a useful bug report. This is what I really need a book on. AFAICT, I would have to compile Perl/Tk myself using certain options, and the options that work for most C software don't actually seem to be the right ones for Perl/Tk. Then I would have to dust off my decades-old C and C debugging skills and figure out what was wrong. Ugh!

Re:no argument... (Score:2)
by bcrowell (177657) on Wednesday December 07, @04:26PM (#14205278)
(http://www.lightandmatter.com/)
BTW, the only real success I know with respect to digital-age publishing is Baen Books.

There are a lot more --- see my sig.

[ Reply to This ]

Whatever bad things you might say about proprietary software, one good thing in terms of reliability is that it's typically statically linked. That means someone who sells a proprietary app can test with a particular version of a library, and then just keep on shipping the app with that version linked in. If a later version of the library comes along that they do want to switch to, they can test it carefully, and then roll it out. But as an OSS programmer, you're at the mercy of your users -- they could install any version of a library, and if it doesn't work right, they consider it to be your fault.

Hmm...I was wrong. Actually their unrealistic placement of the c.m. results in an answer that's too big, because it makes their angle theta be much too small (66 degrees, when it should be more like 76 degrees). For anyone who's really interested, I've incorporated a full analysis in my online physics textbook (section 5.4).

1. Illegal music copying over file-sharing networks is not in any way analogous to supporting the real free information movement. Supporting the real free information movement would mean, e.g., helping out on an OSS project, or writing and recording your own music and intentionally releasing it for free on the internet. Warezing and illegal MP3 sharing just help to give the real free information movement a bad name in the eyes of people who don't really understand much about it.
2. The GPL's enforceability depends entirely on the enforceability of copyright law. If you're wishing for copyright to become unenforceable because of the anonymous nature of the internet, you'd better be planning on a future in which the GPL is roadkill.
3. People who do this kind of copyright violation naturally try to hide their identities, and the copyright owners really do have a problem identifying who they are. For instance, I wrote a book, which is available under a creative commons license. I found out recently that someone has plagiarized a bunch of material from it and put it on a web site, without crediting me, and without reproducing the copyright and licensing information. All of the contact info in the whois database turns out to be bogus, so I haven't been able to contact him via e-mail, phone, or paper mail. I eventually found out who his webhost is, and they seem reasonably responsive so far, but anyway it's not surprising that the RIAA is having a hard time sometimes figuring out who's who, and may even make honest (gasp!) mistakes.

I'm not saying that this particular woman is wrong. I'm not saying that I like current copyright law. (The terms should not be effectively permanent, and the rights of first use, personal use, and first sale have been eroded way too much.) I just think it's way too easy to go with the Slashdot groupthink effect and say "RIAA sucks."

If you can at least sing major scales, then I think practicing from a book like "Music for Sight Singing" by Robert W. Ottman (ISBN 0-13-189662-8) might be helpful.
A free alternative to Ottman: Eyes and Ears

For those who want something really lean and mean, try my app, called When.

For my own needs as a science teacher who doesn't teach online courses, I wrote Spotter, which is open source. Also check out LON-CAPA.

Cory Doctorow:

Eastern Standard Tribe (CC)
A Place So Foreign (and eight more) (CC)
Down and Out in the Magic Kingdom (CC)

Lawrence Lessig:

Free Culture

Tech and science books:

Version Control with Subversion (CC)
An open source math book
Light and Matter, a series of physics texts by Ben Crowell

Lists:
The Assayer is a place to find and review open books.

1. If you have to sue somebody for infringement, you have more remedies available if you did the registration.
2. It proves that you really were the author, and that you wrote it first.

On a different topic, I have some exeprience with bypassing the traditional book publishing industry with some of my own free-as-in-speech books. Here's some advice:

• Keep your expectations reasonable, and make sure that if you never see a dime of revenue, you'll still have had a good time doing it, and won't have lost any money you couldn't afford to lose.
• Don't underestimate how much work it is to set up all the functions of a publisher (or in your case, record label). Taking credit card orders is a pain to set up, and entails continuing hassles. Are you going to have https on your site? -- another hassle, and another expense. What's going to happen with orders if you go on vacation? If you're cursed with success, how much bandwidth are you going to need, and what kind of webhosting costs will that bring with it? How are you going to advertise? Advertising is expensive, and it can be hard to tell if you've reached the right audience, or what the return was on a particular amount of money you spent on advertising.

More worrisome, the x-rays being emitted out the front are carefully regulated for health reasons.
Information here and here. The dosage is extremely low, which is because glass is basically opaque to low-energy x-rays. If your friend spends a couple of hours inside sitting in front of (or behind) a CRT, while you spend the same time outside in the sun, you'll incur the higher risk of cancer, due to the sun's U.V.

However, it's not clear to me how they decide what to index. There doesn't seem to be any explanation of that under Yahoo's "Learn more..." link. When I tested the Yahoo index, they had indexed this book, which was already catalogued on commoncontent.org, but not this one, which isn't. So are they simply grabbing everything linked to from commoncontent.org? In general, I don't see how this could really work well, unless they did something like what commoncontent.org gave up trying to do: let people submit listings, and then have a human check whether they're legit.

However, it's not clear to me how they decide what to index. There doesn't seem to be any explanation of that under Yahoo's "Learn more..." link. When I tested the Yahoo index, they had indexed this book, which was already catalogued on commoncontent.org, but not this one, which isn't. So are they simply grabbing everything linked to from commoncontent.org? In general, I don't see how this could really work well, unless they did something like what commoncontent.org gave up trying to do: let people submit listings, and then have a human check whether they're legit.

I have some of my own books going through the Google Print pipeline. Mine are copylefted, and in fact they're available as complete PDFs online, for free, so unlike many participating publishers, I didn't have any concerns about limiting access. In my Google Print account, I have a settings page that includes this:

• Percent browsable [ edit ]
• 
  Google protects your content by limiting the number of pages that are shown to users. Although users will be able to search over 100% of each book, you can set how much of each book will be shown using the edit link above. For example, setting the Percent browsable to 20% will allow a user to view up to 20 pages of a 100 page book each month.
  % of book users can see: 100%

BTW, it looks like Google is bringing everything online slowly and gradually. For several months now, the status of my books has been

• Processed: your book has been scanned and the file has been sent to be processed and included in our index

Also, there are the Light and Matter books available:

http://www.lightandmatter.com/

The most pathetic thing of all is the check-the-box form that people keep posting on Slashdot purporting to show that a particular method of ending spam won't work. It's become a substitute for intelligent discussion. People just check the boxes, and don't bother to justify which ones they checked. So to save everyone time in the future, here is a perl script that fills in the form automatically:

#!/usr/bin/perl

print "Your post advocates a\n\n";
$n=4;
$approach = int(rand($n));
@approaches = ('technical','legislative','market-based','vigilan te');
for ($i=0; $i<$n; $i++) {
if ($i==$approach) {print "(*)"} else {print "( )"}
print " $approaches[$i] ";
}

$form = <<'FORM';

approach to fighting spam. Your idea will not work. Here is why it won't work. (One or more of the following may apply to your particular idea, and it may have other flaws which used to vary from state to state before a bad federal law was passed.)

( ) Spammers can easily use it to harvest email addresses
( ) Mailing lists and other legitimate email uses would be affected
( ) No one will be able to find the guy or collect the money
( ) It is defenseless against brute force attacks
( ) It will stop spam for two weeks and then we'll be stuck with it
( ) Users of email will not put up with it
( ) Microsoft will not put up with it
( ) The police will not put up with it
( ) Requires too much cooperation from spammers
( ) Requires immediate total cooperation from everybody at once
( ) Many email users cannot afford to lose business or alienate potential employers
( ) Spammers don't care about invalid addresses in their lists
( ) Anyone could anonymously destroy anyone else's career or business

Specifically, your plan fails to account for

( ) Laws expressly prohibiting it
( ) Lack of centrally controlling authority for email
( ) Open relays in foreign countries
( ) Ease of searching tiny alphanumeric address space of all email addresses
( ) Asshats
( ) Jurisdictional problems
( ) Unpopularity of weird new taxes
( ) Public reluctance to accept weird new forms of money

( ) Huge existing software investment in SMTP
( ) Susceptibility of protocols other than SMTP to attack
( ) Willingness of users to install OS patches received by email
( ) Armies of worm riddled broadband-connected Windows boxes
( ) Eternal arms race involved in all filtering approaches
( ) Extreme profitability of spam
( ) Joe jobs and/or identity theft
( ) Technically illiterate politicians
( ) Extreme stupidity on the part of people who do business with spammers
( ) Dishonesty on the part of spammers themselves
( ) Bandwidth costs that are unaffected by client filtering
( ) Outlook

and the following philosophical objections may also apply:

( ) Ideas similar to yours are easy to come up with, yet none have ever been shown practical
( ) Any scheme based on opt-out is unacceptable
( ) SMTP headers should not be the subject of legislation
( ) Blacklists suck
( ) Whitelists suck
( ) We should be able to talk about Viagra without being censore

I've actually written some stuff on Wikibooks. A book like this would be a huge win for Wikibooks, and I want to add my voice to suggest this approach.

If not that, then at least look at Light and Matter by Benjamin Crowell This is an excellent undergraduate Physics textbook that is released under the GFDL. At the time he created the textbook, Wikibooks wasn't available, so he created his own infrastructure to get it going. Mr. Crowell is very approachable as well. If the author of this Quantum Computing textbook wants to go it alone, at least register this book with Crowell's free book registry and review guide.

I am not so sure that /. is the best forum for something like this, due to the fact that it takes some time to grok this book, and unfortunately is a little above the heads of far too many /. readers. In addition, the nitpicking that needs to be done to get something like this going should at least be done chapter by chapter.

For example, in Chapter One there is an incorrect remark about Gordon Moore's Law. He originally proposed a doubling every year, then suggested in a subsequent talk it would slow to double chip density (and much else) every two years. Some biographers and industry journalists were the ones that split the difference and made it 18 months. It is stuff like this that in a textbook situation can help to prepetuate misinformation, not to mention how this can open a can of worms if you are not careful, even though the discussion of Moore's Law is appropriate for the subject matter.

Here's a more detailed discussion of the design.

It's a shame that there's so much chaos in the world of p2p file sharing, arising from all the copyright-violating activity. There are a lot of cool legal ways the technology could be used, but the lawsuits and adware create an environment that make me not even want to touch it. For instance, my wife has just released her CC-licensed French textbook, and she has a bunch of audio files that go along with it (total of about 600 Mb). It would be nice to be able to point people to a way to download the MP3s via a p2p network, because it sure isn't economically feasible to host them for free on an http server. Oh well, I guess we'll just have to give the audio files to people by mailing them CDs, as if the internet didn't even exist. Of course that locks out a lot of people who otherwise might have downloaded the audio -- homeschoolers, etc. It's really frustrating how the free information movement is being held back by people whose idea of free information is the Paris Hilton video.

• Relativity Simply Explained, Martin Gardner (nonmathematical)
• The New World of Mr Tompkins: George Gamow's Classic Mr Tompkins in Paperback, Gamow et al. (nonmathematical)
• Spacetime Physics, Edwin F. Taylor, John Archibald Wheeler
• The Modern Revolution in Physics, by me, free download

It didn't work.

Judging from the e-mails I've received, 100% of the users of my GUI app are running it on Unix. I never had a single student say anything to me (positive or negative) about trying the apps on the bootable CDs. Many of my colleagues run Firefox, but none of them have the faintest interest in switching to a free OS. (The ones who don't like Windows all use MacOS X.)

I feel that:

1. All my effort was wasted.
2. The effort required to make my GUI app cross-platform was way more than I'd anticipated (mainly because of the vastly increased effort required for testing and debugging), and sucked my time away from other contributions I could have made to the free information movement.
3. OSS really cannot exist within the Windows ecosystem. Why do people use Windows? The reasons are typically (a) they're clueless, (b) they have to use Windows at work, and (c) they're clueless. They are the worst possible people to try to evangelize. Their whole conception of "free" is that it has to do with warezing, downloading Britney Spears MP3s, and running a copy of Windows that they got from a friend.

Logically, MacOS X users would be more logical people to try to get interested in OSS. However, what's the point? MacOS is now, what, 2% of the desktop? If you had the biggest home run ever with your cross-platform app that runs on MacOS X, it would still be a miniscule number of people you'd be reaching, and even if they did end up switching to Linux (which is highly unlikely), it wouldn't increase overall diversity in operating systems.

Although the parent post makes a good point about using Windows versions of OSS to let people evaluate the software, I think in most cases the same thing could be accomplished with a bootable Linux CD.

• I disagree - van Gogh, Michaelangelo and Leonardo, all taught themselves technique and then got to where they were through relentless practice and perseverance. Figure studies, copies, sketches, early drafts, training - none of these artists works just suddenly appeared.

1. There's no secret ingredient to artistic creativity. Inspiration doesn't just come along and hit you. Take a look at Beethoven's notebooks --- a seemingly simple idea like the opening bars of the 5th symphony was actually the result of many, many revisions.
2. You have to practice your technique. It's hard work.
3. You should attempt things that are within the range of difficulty that your technique allows you to do competently.
4. Seek out people who know about your art form, and who are willing to tell you when you suck.
5. Over time, learn why those knowledgeable people think certain things suck, learn to detect and throw out your own failures, and eventually learn not to make those mistakes in the first place.

• book cover
  web page banner

Actually, having books online for browsing increases sales.
This is what has happened with the Baen Free Library, and it's also happened with my own books, and books from some some other publishers. It may not be universally true for every type of book, however. For instance, some college textbooks are so overpriced that students really are motivated strongly to photocopy them, etc. This book, for example, is $134, which is just insane.

Baen has done it, and it worked great. Cory Doctorow has done it (I think his publisher is Tor), and it worked great. I've done it, and it worked great.

There's also some interesting speculation as to whether or not he was gay -- here, there's less evidence one way or the other, but his nervous breakdown may have been caused by the ending of his relationship with a much younger man, Fatio de Duiller (?).

I'm not a DNS guru, so can someone use crayons with me -- how do I actually go about registering my domains to support SPF on outgoing mail? There's this webapp for creating the text of the SPF record, but then what? Would the registrar have to provide a mechanism for me to add the record? The web host?

The author of the article doesn't seem to understand the experiment himself. Probably he's misunderstanding Deutsch, whom he's apparently just paraphrasing. The whole experiment he's describing is simply a classical diffraction experiment, and can be explained using only the plain old classical wave theory of light. There's nothing quantum mechanical about it, so it doesn't have anything to do with the many-worlds interpretation of quantum mechanics. The part about changing from two pinholes to four is just nonsense. The case with two pinholes is classical physics that's been understood for almost 200 years. The case with four pinholes is also classical physics that's been understood for almost 200 years. Maybe Deutsch had an interesting point to make about the comparison, but if so, then the author of the article doesn't seem to have understood it.

The experiment described in chapter 2 of this book is the simplest I know of if you actually want to see the quantum stuff going on. Basically you just need to modify a digital camera. I haven't done it myself; the figures in my book are from a profesor at Princeton who built it as a classroom demonstration.

Even if you do the version of the experiment that does prove that light is simultaneously a particle and a wave, that doesn't constitute a proof of the many-worlds interpretation of quantum mechanics. There are various interpretations of quantum mechanics, all of which make identical predictions about experiments. Most people think and talk about it using either the Copenhagen interpretation or the many-worlds interpretation. Neither is right or wrong, because neither one makes a prediction that contradicts the other.

The author of the article doesn't seem to understand the experiment himself. Probably he's misunderstanding Deutsch, whom he's apparently just paraphrasing. The whole experiment he's describing is simply a classical diffraction experiment, and can be explained using only the plain old classical wave theory of light. There's nothing quantum mechanical about it, so it doesn't have anything to do with the many-worlds interpretation of quantum mechanics. The part about changing from two pinholes to four is just nonsense. The case with two pinholes is classical physics that's been understood for almost 200 years. The case with four pinholes is also classical physics that's been understood for almost 200 years. Maybe Deutsch had an interesting point to make about the comparison, but if so, then the author of the article doesn't seem to have understood it.

The experiment described in chapter 2 of this book is the simplest I know of if you actually want to see the quantum stuff going on. Basically you just need to modify a digital camera. I haven't done it myself; the figures in my book are from a profesor at Princeton who built it as a classroom demonstration.

Even if you do the version of the experiment that does prove that light is simultaneously a particle and a wave, that doesn't constitute a proof of the many-worlds interpretation of quantum mechanics. There are various interpretations of quantum mechanics, all of which make identical predictions about experiments. Most people think and talk about it using either the Copenhagen interpretation or the many-worlds interpretation. Neither is right or wrong, because neither one makes a prediction that contradicts the other.

The author of the article doesn't seem to understand the experiment himself. Probably he's misunderstanding Deutsch, whom he's apparently just paraphrasing. The whole experiment he's describing is simply a classical diffraction experiment, and can be explained using only the plain old classical wave theory of light. There's nothing quantum mechanical about it, so it doesn't have anything to do with the many-worlds interpretation of quantum mechanics. The part about changing from two pinholes to four is just nonsense. The case with two pinholes is classical physics that's been understood for almost 200 years. The case with four pinholes is also classical physics that's been understood for almost 200 years. Maybe Deutsch had an interesting point to make about the comparison, but if so, then the author of the article doesn't seem to have understood it.

The experiment described in chapter 2 of this book is the simplest I know of if you actually want to see the quantum stuff going on. Basically you just need to modify a digital camera. I haven't done it myself; the figures in my book are from a profesor at Princeton who built it as a classroom demonstration.

Even if you do the version of the experiment that does prove that light is simultaneously a particle and a wave, that doesn't constitute a proof of the many-worlds interpretation of quantum mechanics. There are various interpretations of quantum mechanics, all of which make identical predictions about experiments. Most people think and talk about it using either the Copenhagen interpretation or the many-worlds interpretation. Neither is right or wrong, because neither one makes a prediction that contradicts the other.

Also, I find it unlikely that this will really catch on, simply because most of the professors I've dealt with simply would not consider a textbook like this, or wouldn't even be aware of it.
I've written some open-source physics textbooks that have been adopted at eighteen schools. Not trying to blow my own horn -- I just wanted to provide a counterexample.