From: Trans Date: 2007-10-15T01:17:10+09:00 Subject: Re: MIT vs. Ruby/GPL License On Oct 14, 8:29 am, Randy Kramer wrote: > On Sunday 14 October 2007 09:31 am, Trans wrote: > > > Rails uses the MIT license. The Ruby license is essentially the GPL > > (it's a dual license). > > > So what are the basic differences between the two and why would you > > pick one over the other? > > Interesting question, and one I'm tempted to answer even though others are > certainly better quailified. (I.e., IANAE(xpert)) I guess I'll consider this > a learning exercise, to see how much I do know. > > (Aside: I'm curious: I'm a little surprised you haven't come across and come > to some resolution on the issues involved--do you program primarily in > Windows as opposed to Linux?) Me too ;) I've been using the Ruby license. But everything I've done until now has been purely open. That's about to change though, so the question becomes a more important one. > I have trouble remembering things, I remember less about the MIT license than > the GPL license, and know (if I can remember) most about the GPL version 2. > > First of all both the MIT and GPL licenses are in some sense "free". > > The meaning of free in this context is freedom as opposed to free beer. > > Richard Stallman, the guy who, at least in some sense, started the drive > towards a free operating system, originated and advocates the GPL license. > He lists four freedoms that could be associated with software--can I remember > them to recite them or must I look them up? > > Hmm, I guess I'll refer you to the following page which contains the GNU's > "Free Software Definition" (gnu is (one of?) the organizations founded by > Richard Stallman, the other being the FSF (or are they the same > organization--I guess I don't really know)): > > http://www.gnu.org/philosophy/free-sw.html > > When you read over that page, pay particular attention to "copyleft"--the > primary difference between the GPL and other free (??) licenses (like the MIT > license) is the copyleft part--the GPL requires copyleft, many others (MIT, > BSD, ... do not). (Richard Stallman considers free licenses without copyleft > to be non-free.) > > I anticipate releasing any software I write under the GPL license. > > There are other choices like dual licenses and, hmm, I forget what they call > them, but like what Ghostscript and some others do--(iirc) they initially > release their software (i.e., current versions) under a license other than > the GPL, and then after some period of time (or at the release of the next > version) they release the older version under the GPL. > > Aside: If you get into dual licenses, take any recent writings on the subject > by Theo de Raadt (the OpenBSD founder) with a grain of salt--in a fairly > recent dispute, he made the claim that dual licenses required that the terms > of both licenses be applicable, whereas most dual licenses are specified with > an "or" (you can license it this way or that way--of course a dual license > could be written with an "and"--I'm not sure that would be useful in any > way). > > BTW, other issues to consider are which software can be intermixed in some way > even though they use different licenses. > > Another way of looking at it the general subject is this: > > With a license like the MIT (and BSD, and ...) you give away your software > (almost) unconditionally, anybody can take your software and use it for any > purpose without returning anything to you (they can make a proprietary > package from it, make a fortune, and not share anything with you). So MIT is more akin to BSD --less restrictive. > With a license like the GPL, your software gift is conditional--the receiver > of the gift must (to use a phrase that I haven't heard in this context > before) "pay it forward". In other words, they must keep the gift available > including any improvements they may make. > > You can make money with either type of license, but it is ususally by means of > a service model than a use model. To clarify, a way of making money with > free software is selling support for it, as opposed to selling a license for > its use. > > Note that the GPL does allow you to charge for the software, but anyone who > buys your software can re-distribute it at a lower price, down to zero (or > negative numbers??). > > There is also a (potential) different issue (??) related to selling the source > code--the intent (and words), iirc, is that you can only recoup your > (copying) costs (or a reasonable fee--I forget what it says) for the source > code. > > At most, this is just a start. Do some reading and ask some questions. Very helpful thank you. For the moment I will hone in on one question: If a gem is released under GPL and your app depends on it, does that mean your source must also be freely available in a way compatible to the GPL? If not, then what about if you drop the same library into your vendor/ directory and redistribute it along with your app? Thanks, T.