The only DTDs I have found whose license agreement is open enough to allow
me to republish and discuss them in my book are the few explicitly adopted
by the W3C. The rest have copyright statements that most often explicitly
prohibit me from using them. Many of them are so restricted that it's not
permissible to use the DTD in a document of my own creation, much less
modify it to fit my needs.
So far authors I have contacted personally have been very receptive to
allowing me to use their DTDs, and in most cases it's been obvious that
their intent was to allow broader use. Nonetheless before I can use any of
these in a book, I'm going to have to get them to sign a two-page contract
dreamed up by IDG's lawyers. I expect many of them to refuse, because it is
a bad contract. I blame IDG's lawyers for that problem.
No contract should be necessary, however. The whole point of XML is to
allow broad, standardized documents. To this end any markup language that's
created, whether described in a DTD, a DCD, an XSchema, or something else,
must explicitly allow itself to be reused and reprinted without prior
permission. Right now I'm worried about reprinting it in books, but the
problem of including these DTDs on web sites is even more crucial.
My preference is that these DTDs be placed in the public domain, because
it's simplest and easiest to explain to lawyers. Open source works well
too. Even a copyright statement that allows reuse but not modification is
adequate for many needs, including most of mine.
However, a DTD that simply includes a standard copyright statement
immediately becomes unusable in many corporations. While I expect many
people and companies will simply ignore these restrictions (which the
authors never intended anyway) I don't think many people will be
comfortable relying on this in our overly litigious world.
Therefore I want to implore all authors of published DTDs to go back and
look at your copyright statements. Ask yourself, "What does this really
say? What do I want people to do with this DTD? Are they actually allowed
to do that?" There's very little to be gained by writing a DTD you hope an
industry will adopt, if you explicitly or implicitly prohibit the industry
from adopting it.
+-----------------------+------------------------+-------------------+
| Elliotte Rusty Harold | elharo@sunsite.unc.edu | Writer/Programmer |
+-----------------------+------------------------+-------------------+
| XML: Extensible Markup Language (IDG Books 1998) |
| http://www.amazon.com/exec/obidos/ISBN=0764531999/cafeaulaitA/ |
+----------------------------------+---------------------------------+
| Read Cafe au Lait for Java News: http://sunsite.unc.edu/javafaq/ |
| Read Cafe con Leche for XML News: http://sunsite.unc.edu/xml/ |
+----------------------------------+---------------------------------+