The Patent Paradox
By Michael Floyd
When members of the World Wide Web Consortium received a proposal this past August to consider a new industry protocol called the Distribution and Replication Protocol (DRP), they had no idea they would become caught between two software companies battling bitterly over a patent-infringement dispute. DRP could change the way software is distributed via the Web: Its key element is a mechanism that detects a user's configuration and updates only those files that have changed from a previous version. Furthermore, the proposal defines a "Differential ID" that can be used to calculate those portions of a file that have changed on the server. Thus, a client could issue a "differential GET" request. When the server received the request, it could look in its file cache for both versions of the requested file, compute the difference between the two, and return the "diff" rather than the entire file. And herein lies the rub.
In 1993, a medium-sized software development company called Novadigm filed an application with the U.S. patent office for "Distributed Computer Network Including Hierarchical Resource Information Structure and Related Method of Distributing Resources." The patent describes a process known as "fractional differencing," which, when combined with "desired state processing" allows for incremental software updates based on the optimum configuration of a particular machine. Novadigm, which produces configuration-management software to manage software distribution over networks, was granted the patent in December 1996.<>
