🚀 go-pugleaf

First of all, it might be useful to actually find out what is covered
by the patent.  In particular, Pike did some very nice work on the
Blit, which he wrote up in a now famous article entitled "Graphics in
overlapping bitmap layers."  It would not surprise me if the
algorithms he described were patented by AT&T Bell Labs.  They aren't,
however, a generic implementation of "backing store" as we know it.
Rather, they allow a system to store offscreen *only* the obscured
parts of a window, and to present a rendering API that makes it look
like all of the window is visible.  This is the most elegant software
implementation of backing store that I've ever seen.

My question is, does the AT&T patent cover backing store in general,
or Pike's implementation?  If it's the latter, it should be easy to
work around, at the cost of slightly greater memory usage.  If it's
the former, an uninformed court could conceivably interpret it to
cover all sorts of bitmap caching for displays.  This would be a bad
thing, IMHO.

So, has anyone seen the actual patent?
-- 
Amanda Walker						      amanda@visix.com
Visix Software Inc.					...!uunet!visix!amanda
--
"C++ is like a glass of buttermilk: the taste doesn't bother you so much;
 it's what it does to the glass afterwards."	--Kurt Schmucker