At 09:00 AM 9/1/99 -0700, you wrote:
>I have ported several programs that were available on the 
>Smalltalk Archive (hanoi, wires, ropes, USA) as part of my
>learning process. 
>
>My product is based on someone else's original work, but 
>includes (sometimes substantial) changes to make it work in
>Squeak.
>
>I have received  permission to use some code, is it enough
>to state in the comments that the code is based on <foo>
>written by <bar> or do I need to specify the differences
>between the original and my version.
>
>If someone then asks me if they can use this new program
>can I give them permission for all of it or just my part?
>
>Thanks,
>
>John-Reed Maffeo
>Mesa, Arizona

I am not an attorney but I have dealt with software legal issues for many years
so take this as you may.

If someone marks their software with a copyright message it's copyrighted
period.  Once you gain access to copyrighted software you cannot do anything
with ANY part of it without express permission.  You can't use any part of 
copyrighted software regardless of how much you change it or how small
a piece without express permission.  "based on" messages mean nothing
and are only a courtesy (unless the author requires it as part of his
permission).
Further, you can't distribute (give copies) of any part of any software you
don't have rights or permission to.

--blake

-------
Download source code to my Dynace Object Oriented
Extension to C and Windows Development System from:
http://www.florida-software.com/algorithms
Blake McBride (blake at florida-software.com)
Algorithms Corporation - 615-791-1636 - USA