Hello!

On Sun, Sep 16, 2007 at 05:12:08PM -0400, Theodore Tso wrote:
quoted text
>[...]

quoted text
>What is going on whenever someone changes a code is that they make a
>"derivative work".

Only if the additions/changes are significant enough to be copyrightable
on their own.

quoted text
>Whether or not you can even make a derivative
>work, and under what terms the derivitive work can be licensed, is
>strictly up to the license of the original.  For example, the BSD
>license says:

quoted text
>  Redistribution and use in source and binary forms, with or without
>  modification, are permitted provided that the following conditions
>  are met....

quoted text
>Note the "with or without modification".  This is what allows people
>to change BSD licensed code and redistribute said changes.  The
>conditions specified by the BSD license do not mention anything about
>licening terms --- just that if you meet these three conditions, you
>are allowed to redistribute them.  So for example, this is what allows
>Network Appliances to take BSD code, change it, and add a restrictive,
>proprietary copyright.

Right. You may add nearly any copyright *on your own significant
additions/changes*. However, BSD/ISC explicitly requires to retain the
BSD/ISC terms, too (applicable to the original part of the combined
work).

quoted text
>So for code which is single-licensed under a BSD license, someone can
>create a new derived work, and redistribute it under a more
>restrictive license --- either one as restrictive as NetApp's (where
>no one is allowed to get binary unless they are a NetApp customer, or
>source only after signing an NDA), or a GPL license.  It is not a
>relicencing, per se, since the original version of the file is still
>available under the original copyright; it is only the derived work
>which is under the more restrictive copyright.   

No. The derivative work altogether has a *mixed* license. BSD/ISC for
the parts that are original, the other (restrictive, GPL, whatever)
license for the modifications/additions.

*If* you choose to distribute source along with the binaries, the part
of the source that's original is BSD/ISC licensed even in the derivative
work (though one may put *the additions/modifications* under restrictive
conditions, e.g. of commercial non-disclosure type source licensing).

quoted text
>[... dual-licensing issues etc. already handled in other mails ...]

Kind regards,

Hannah.