Copyleft/guide Changeset - d5864804ba05

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@@ -1638,8 +1638,8 @@ distribution (more on that later).

Under GPLv2~\S3(a), the source code provided must be the ``corresponding source

code.''  Here ``corresponding'' primarily means that the source code

provided must be that code used to produce the binaries being distributed.

That source code must also be ``complete.''  A later paragraph of GPLv2~\S3

explains in detail what is meant by ``complete.''  In essence, it is all

That source code must also be ``complete''.   GPLv2~\S3's penultimate paragraph

explains in detail what is meant by ``complete''.  In essence, it is all

the material that a programmer of average skill would need to actually use

the source code to produce the binaries she has received.  Complete source

is required so that, if the licensee chooses, she should be able to

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@@ -1648,7 +1648,7 @@ complete source, it would not be possible to make changes that were

actually directly derived from the version received.

Furthermore, GPLv2~\S3 is defending against a tactic that has in fact been

seen in FSF's GPL enforcement. Under GPL, if you pay a high price for

seen in GPL enforcement.  Under GPL, if you pay a high price for

a copy of GPL'd binaries (which comes with corresponding source, of

course), you have the freedom to redistribute that work at any fee you

choose, or not at all.  Sometimes, companies attempt a GPL-violating

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@@ -1663,9 +1663,9 @@ manner, those further down the distribution chain are assured that

they have the unabated freedom to build their own derivative works

from the sources provided.

FSF (as authors of GPL) realizes that software distribution comes in many

Software distribution comes in many

forms.  Embedded manufacturers, for example, have the freedom to put

GPL'd software into their PDAs with very tight memory and space

GPL'd software into mobile devices with very tight memory and space

constraints.  In such cases, putting the source right alongside the

binaries on the machine itself might not be an option.  While it is

recommended that this be the default way that people comply with GPL, the

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@@ -1673,24 +1673,22 @@ GPL does provide options when such distribution is infeasible.

GPLv2~\S3, therefore, allows source code to be provided on any physical

``medium customarily used for software interchange.''  By design, this

phrase covers a broad spectrum. At best, FSF can viably release a new GPL

every ten years or so. Thus, phrases like this must be adaptive to

changes in the technology. When GPL version 2 was first published in June

phrase covers a broad spectrum --- the phrase seeks to pre-adapt to

changes in  technology.  When GPLv22 was first published in June

1991, distribution on magnetic tape was still common, and CD was

relatively new. Today, CD is the default, and for larger systems DVD-R is

gaining adoption. This language must adapt with changing technology.

relatively new.  By 2002, CD is the default.  By 2007, DVD's were the

default.  Now, it's common to give software on USB drives and SD card.  This

language in the license must adapt with changing technology.

Meanwhile, the binding created by the word ``customarily'' is key.  Many

incorrectly believe that distributing binary on CD and source on the

Internet is acceptable. In the corporate world, it is indeed customary to

simply download CDs worth of data over a T1 or email large file

attachments. However, even today in the USA, many computer users with

CD-ROM drives are not connected to the Internet, and most people connected

to the Internet are connected via a 56K dial-up connection. Downloading

Internet is acceptable.  In the corporate world in industrialized countries, it is indeed customary to

simply download a CDs' worth of data quickly.  However, even today in the USA, many computer users are not connected to the Internet, and most people connected

to the Internet still have limited download speeds.  Downloading

CDs full of data is not customary for them in the least.  In some cities

in Africa, computers are becoming more common, but Internet connectivity

is still available only at a few centralized locations.  Thus, the

``customs'' here must be normalized for a worldwide userbase. Simply

``customs'' here are normalized for a worldwide userbase.  Simply

providing source on the Internet --- while it is a kind, friendly and

useful thing to do --- is not usually sufficient.

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@@ -1706,8 +1704,7 @@ As is shown above, Under GPLv2~\S3(a), embedded manufacturers can put the

binaries on the device and ship the source code along on a CD\@.  However,

sometimes this turns out to be too costly.  Including a CD with every

device could prove too costly, and may practically (although not legally)

prohibit using GPL'd software. For this situation and others like it, \S

3(b) is available.

prohibit using GPL'd software. For this situation and others like it, GPlv2\S~3(b) is available.

GPLv2~\S3(b) allows a distributor of binaries to instead provide a written

offer for source code alongside those binaries.  This is useful in two

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@@ -1730,7 +1727,7 @@ support engineers must be trained how to route source requests, and

source CD images for every release version for the last three years

must be kept on hand to burn such CDs quickly. The requests might not

even come from actual customers; the offer for source must be valid

for ``any third party.''

for ``any third party''.

That phrase is another place where some get confused --- thinking again

that full public distribution of source is required.  The offer for source