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From: jaf...@zurich.ai.mit.edu (Aubrey Jaffer)
Newsgroups: comp.graphics,comp.windows.x
Subject: X Consortium Announcement about AT&T Patent
Message-ID: <JAFFER.91Sep25175004@zohar.ai.mit.edu>
Date: 25 Sep 91 21:50:04 GMT
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Organization: M.I.T. Artificial Intelligence Lab.
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For more info contact lea...@ai.mit.edu (League for Programming Freedom).
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September 24, 1991

Memorandum to:	Members of the X Consortium

Subject:	U. S. Patent No. 4,555,775 (Pike), Issued to AT&T on 	November 26, 
1985 for "DYNAMIC GENERATION 	AND OVERLAYING OF GRAPHIC WINDOWS"

In February 1991, AT&T sent letters to MIT and to members of the X Consortium, 
notifying the community that the "backing store" functionality available in 
the X Window System is an implementation of a patented AT&T invention, and 
that consequently, companies or institutions commercially marketing or 
internally developing products based on an X Window System implementation will 
need a license from AT&T.  Since MIT developed the X Window System and 
distributes it widely, we were deeply concerned by AT&T's action, and we 
conducted a thorough technical analysis of the patent and similar window 
system technology.  MIT also retained counsel to provide us with an expert 
legal opinion.  Both our technical analysis and the legal opinion conclude 
that AT&T's claim with respect to the X Window System cannot be sustained.

Patent #4,555,775 was applied for in 1982 by Robert Pike and issued in 1985 to 
his employer, Bell Laboratories.  It describes a variation of graphics drawing 
algorithms that enables a single display screen to support overlapping 
windows, in which several programs can be active simultaneously.  It is our 
opinion that this same capability was present in window systems that predated 
the Bell Laboratories' work.

The Bell Laboratories' work, the X Window System, and previous window systems 
all use different variants of the same basic methodology (storing obscured 
regions of windows as off-screen bit maps).  Both our legal and technical 
analyses agree that each of the patent's claims is either so broad as to have 
been anticipated by prior art, or so narrow as to apply only to the `775 
patent's specific algorithm and not to the X Window System.

AT&T has requested the Patent Office to open the `775 patent for 
reexamination, which will give AT&T an opportunity to clarify the patent's 
claims.  We hope that AT&T will seek there to recognize the contribution of 
the work on which it is based while not casting its claims beyond the specific 
methodology involved.  MIT is very willing to work with AT&T toward reaching 
this goal and is exploring ways in which this can be done.

>From a broader perspective, the confusion over the `775 patent illustrates the 
difficulties raised by the increasing number of patents issued on software 
technology.  We would welcome the opportunity to join with AT&T, other 
companies, and the university community to explore ways to alleviate these 
problems.  Software is an area in which prior art is often difficult to 
identify and in which obviousness differs significantly from one perspective 
to another.  The recent proliferation of software patents is creating pressure 
on software developers to seek patent protection for straightforward ideas, 
and increasing pressure to claim broad applicability of software patents, well 
beyond the scope of any original invention.  These practices introduce a 
chilling effect on university research, and they undermine our ability to 
pursue ideas in a free and open climate.  In as much as these practices attack 
the university's central goals and its obligation to disseminate information, 
they are a matter of utmost seriousness to MIT.