Re: TeX Licenses & teTeX (Was: Re: forwarded message from Jeff Licquia)

[tb@becket.net (Thomas Bushnell, BSG)]

Frank Mittelbach <frank.mittelbach@latex-project.org> writes:

> I'm talking of requiring that the work identifies itself by name via
> interface to other works (something that could be checked by a
> computer)

What I want to highlight is how radically different this is from what
TeX actually requires.

You can't change tex.web, but you can do *anything* you like to it, as
long as you do so via patch files.  And in Knuth's wacked out language
(WEB), he even has a decent automatic patch file mechanism *built in*
to facilitate this.

I know of *NO* TeX installation which does not require some patching.
Every single one requires some.  Some do very radical transforations
of tex.web (web2c, for example).  The file is radically changed,
massaged, warped, and the result is then called "TeX".  That's because
the trademark on the word "TeX" comes with a license that says "you
can call this TeX if you really--honestly--are happy with it as TeX,
and if it passes the trip test."  

There is certainly no rule that only unmodified TeX can be called TeX,
since, in fact, *NOBODY* uses an unmodified TeX.  Everyone, in fact,
uses the deliberately-built-in WEB patch mechanism, or an equivalent.

It was just this situation with TeX that was a factor in the wording
of DFSG-4.

Now the situation with the LPPL is *very* different.  Unlike TeX, you
can modify the files as much as you want, but also unlike TeX, you
must rename the filenames--something TeX never requires.

There is no trademark protection at all on the LPPL-covered-works, but
there is a clumsy attempt to get it by restricting the distribution of
modified versions.  Indeed, TeX has almost no restriction on the
distribution of modified versions--except that modifications must be
by patches.  TeX does *not* say that modified versions cannot be
called "TeX"--indeed, it expects, nay, pratically requires this.

Thomas