AT&T Co is starting to enforce the 1985 patent it holds on backing store, a base technology used in most X Window software. Having completed bilateral or patent bartering arrangements with most of the large hardware vendors that are using the backing store component in their systems, AT&T’s Intellectual Property Division is now contacting independent software vendors and telling them they must have a licence. The backing store technology enables a window to store what it covers in another window and then repaint what was stored when needed again. It’s an essential performance device, and AT&T said it considers backing store a crown jewel of its patent portfolio, one of the few of the two or three thousand software patents the company holds that is expected to recoup some of its research and development expense. Needless to say, the fundamental technology originated with Xerox Palo Alto Research Center back in the 1970s, but Xerox consciously and chracteristically decided not to patent it. AT&T is asking independent software vendors to pay either 3% of their revenue stream or a minimum of $5 per unit, whichever is higher, for a licence. It is starting its enforcement campaign by contacting all members of the X Consortium with whom it currently does not have an agreement in place. It will then broaden the list to include all other X suppliers, including hardware companies. AT&T believes the technology will also be heavily used in the MS-DOS community, but it would not indicate whether Microsoft holds a licence for any use in Windows. The X Consortium is expected to go to law to fight AT&T’s claims, and believes it is on strong ground.
