Ugly Huge BSD Monster

[Gary W. Swearingen]

Terry Lambert <tlambert2 at mindspring.com> writes:

> Adobe gives away only the viewer.  They sell the creation tool,
> and they do not give away source code to the viewer.  They guard
> the file format and third party tools via vigorous enforcement
> practices utilizing all tools at their disposal, including the
> DMCA.

Please explain further.  I thought that PDF was a sort of
PostScript-ng, with an unobfuscated (or even documented) file format.
I guess I formed that opinion based on the ability of Ghostscript to
print and view PDF files.  Is it based on reverse engineering PDF
files?  Do PDF files contain IP protection features?  Does Adobe think
its developers and/or users copyright infringers under the DMCA?