🚀 go-pugleaf

The London-based Unigram.X, a Unix-oriented weekly, has in its
recent issue (February 18-22 1991) an short article about AT&T
getting tough on licencing its backing-store patent (issued 1985)
to X software developers. Below is my summary of the article.

According to Unigram.X, AT&T has now completed patent arrangements with
most of the large hardware vendors that use backing store, and is now
contacting independent software vendors telling them to get a licence.
AT&T is said to ask them either 3% of their revenue or a minimum of $5
per unit, whichever is higher. The enforcement is being started by
contacting all those members of the X consortium with whom AT&T has
no agreement yet. It will later contact all other X suppliers. AT&T
would not say whether Microsoft has licenced the backing store for
Windows.

The article describes the patented technology as allowing a window to
store what it covers in another window and then repaint what was stored
when deeded again. AT&T is reported to consider the backing store a
"crown jewel" of its patent portfolio, one of the few of its 2000-3000
software patents that it expects to return some of the R&D investment.
Unigram.X says that the fundamental technology originated in Xerox PARC
in the 1970s, but Xerox consciously decided not to patent it. The X
consortium is expected to legally fight AT&T:s claims, and believes it
is on strong ground.

End of summary. Interestingly, the X documents describe the backing store as
an option that some X servers have, and which must not be relied on. Even in
the unfortunate case of the patent remaining valid, I suppose it is possible
to make a non-infringing X system (unless the patent is found to cover all
temporary saving of data to auxiliary arrays...). This looks like the most
obvious case yet of patenting something that is (and has been) routinely
reinvented by programmers.
--
Erkki Ruohtula     / Nokia Telecommunications
eru@tele.nokia.fi / P.O. Box 33 SF-02601 Espoo, Finland
Disclaimer: These are my private opinions and do not represent the position
            of Nokia Telecommunications.