The USPTO awarded search giant Google a software method patent that covers the principle of distributed MapReduce, a strategy for parallel processing that is used by the search giant. If Google chooses to aggressively enforce the patent, it could have significant implications for some open source software projects that use the technique, including the Apache Foundation’s popular Hadoop software framework.

“Map” and “reduce” are functional programming primitives that have been used in software development for decades. A “map” operation allows you to apply a function to every item in a sequence, returning a sequence of equal size with the processed values. A “reduce” operation, also called “fold,” accumulates the contents of a sequence into a single return value by performing a function that combines each item in the sequence with the return value of the previous iteration.