BSD & MIT licenses compatible?

Suraj N. Kurapati skurapat at ucsc.edu
Sat Apr 14 04:28:12 UTC 2007


Hello,

Please consider the following scenarios to help me better understand
whether BSD* and MIT code are "compatible".

*I am referring to the 3-clause BSD license:

  http://opensource.org/osi3.0/licenses/bsd-license.php


Scenario
========

Suppose that (1) I have two C source files (mit.c and bsd.c) and
that (2) each file is correctly placed under its respective license.


Simple case
-----------

I put mit.c and bsd.c into a tarball and send it to you.

What happens now?

Here is what I think:

  * mit.c remains under the MIT license

  * bsd.c remains under the BSD license


Complex case
------------

Suppose I append bsd.c to the end of mit.c while making sure to
clearly differentiate the two sources. For example:

  echo '/* begin BSD licensed code */' >> mit.c
  cat bsd.c                            >> mit.c
  echo '/* end BSD licensed code */'   >> mit.c

Next I put mit.c and bsd.c into a tarball and send it to you.

What happens now?

Here is what I think:

  * The portions of mit.c that were not copied
    from bsd.c remain under the MIT license.

  * The portions of mit.c that were indeed copied
    from bsd.c remain under the BSD license.

  * bsd.c remains under the BSD license


Remarks
=======

The BSD is not compatible with the MIT license because it has an
additional condition (i.e. you cannot use copyright holder's names
to promote the product) that the MIT license lacks.

Nevertheless, I was able to distribute the tarball in both cases
because I satisfied the distribution conditions of both licenses.


Thanks for your consideration.



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