Re: Jam: which licence is this?

[Jack Hill]

On Sun, 25 Apr 2021, Vagrant Cascadian wrote:

> On 2021-04-25, Jack Hill wrote:
> > I'm working on packaging the Argyll Color Management System for Guix. To
> > build, it uses the Jam tool, which has the following license:
> >
> > ```
> > This is Release 2.5 of Jam, a make-like program.
> >
> > License is hereby granted to use this software and distribute it
> > freely, as long as this copyright notice is retained and modifications
> > are clearly marked.
> >
> > ALL WARRANTIES ARE HEREBY DISCLAIMED.
> > ```
>
> Permission to use, check.
> Permission to study, probably(?)
> Permission to share, check.
> Permission to modify, .... ?
>
> Is it even free software? There is no mention of modification which
> doesn't appear to be free by my layman's reading...

I do see a mention of modification "…modifications are clearly marked." 
Compare with the gnuplot license, for which modifications can only be 
distributed as separate patch files

/*[
 * Copyright 1986 - 1993, 1998, 2004   Thomas Williams, Colin Kelley
 *
 * Permission to use, copy, and distribute this software and its
 * documentation for any purpose with or without fee is hereby granted,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.
 *
 * Permission to modify the software is granted, but not the right to
 * distribute the complete modified source code.  Modifications are to
 * be distributed as patches to the released version.  Permission to
 * distribute binaries produced by compiling modified sources is granted,
 * provided you
 *   1. distribute the corresponding source modifications from the
 *    released version in the form of a patch file along with the binaries,
 *   2. add special version identification to distinguish your version
 *    in addition to the base release version number,
 *   3. provide your name and address as the primary contact for the
 *    support of your modified version, and
 *   4. retain our contact information in regard to use of the base
 *    software.
 * Permission to distribute the released version of the source code along
 * with corresponding source modifications in the form of a patch file is
 * granted with same provisions 2 through 4 for binary distributions.
 *
 * This software is provided "as is" without express or implied warranty
 * to the extent permitted by applicable law.
]*/

ajam clearly marks its modifications by including this in its readme:

"""
This if "Argyll-Jam", a simple derivative of the "FT-Jam" build tool, based and
100% compatible with Jam 2.5. See http://www.freetype.org/jam/ for more
details about FT-Jam.

This is the "FT-Jam" 2.5.2 release, with minor ArgyllCMS tweaks,
and the ArgyllCMS V1.3.3 Jambase as the default rule set.

Note that you'll find the original Jam README in the file README.ORG
"""

Thoughts?
Jack