[Ctk-developers] License versus copyright and authorship

[Luis Ibanez]

On Sun, Jul 10, 2011 at 4:47 PM, Stephen Aylward
<stephen.aylward at kitware.com> wrote:
> Hi,
>
> One point of clarification - I still strongly believe that CTK code
> should clearly indicate who are its authors/contributors.   That is,
> if some of the code came from Slicer, it should indicate it.  If some
> of it came from MITK, it should indicate it.  If J2 wrote it, it
> should indicate it.
>
> Thanks to use of the Apache 2.0 license, we can independently credit
> authorship and list other copyright owners when appropriate.
>
> Thanks,
> Stephen
>
> --
>
> ==============================
> Stephen R. Aylward, Ph.D.
> Director of Medical Imaging Research
> Kitware, Inc. - North Carolina Office
> http://www.kitware.com
> stephen.aylward (Skype)
> (919) 969-6990 x300
> _______________________________________________
> Ctk-developers mailing list
> Ctk-developers at commontk.org
> http://public.kitware.com/cgi-bin/mailman/listinfo/ctk-developers
>
-------------------------------------------------------------

Stephen,

Crediting initial author(s) is feasible in the first commit of a
file, but it becomes impractical as the maintenance of that
file is done over time by other developers (as it should be
the case in an open source project where wide participation
is encouraged).

On day #1, one can clearly say that File X is authored by
developer M, but 1,000 days later, that file is only 75% by
developer M, and now it is also 12% by developer Q,
9% by developers R,..... 0.1% by developer Z...

The Statistical Reports generated by the revision control
system are better suited for keeping track of authorship
and credits.

Over time, the file is a joint work of authorship of over a
dozen people (and their employers...).

Here is for example the "git blame"
summary of "itkImage.h"

      67 Hans Johnson
     49 Will Schroeder
     37 Jim Miller
     32 Luis Ibanez
     20 Brad King
     13 Paul Hughett
      9 Karthik Krishnan
      9 GaA«tan Lehmann
      9 Bill Lorensen
      6 Arnaud Gelas
      4 Mark Foskey
      3 Jisung Kim
      3 David Cole
      1 Vikram Chalana
      1 Bill Hoffman


The first column is number of lines of code
touched by the developer in the second
column.

This is the outcome of
11 years of development.

and this is still incomplete, since it only
shows the authors who modified the
lines of code for the last time.

Tools like gitstat can regularly extract
this information if needed.

For example:
http://public.kitware.com/pub/itk/gitstat/ITK-2011-05-09/index.html

developers (and their employers) only hold
the copyright of the modifications that they
apply to a file, and only when they are over
the level of functional code, that merits to
be considered a work of authorship (think
of a a work of art...).  For example, a for loop
to count a number of elements, is below the
level of being copyrightable.


     Luis