http://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660j23tom, Why so? In the grand scheme of things, a windows license is not that big an expense. Sure, if you have 1000+ machines it is. But this algorithm is equally usable on 5-10 machines, and it will allow you to scale out instead of having to scale up. I do wish that they had made better support for it, so that it was possible to just do out of the box. But I guess it is not that easy. http://ayende.com/4436/what-is-map-reduce-for-anyway#comment4http://ayende.com/4436/what-is-map-reduce-for-anyway#comment4Tue, 16 Mar 2010 09:09:15 GMTone of your better posts in the last time. i like it http://ayende.com/4436/what-is-map-reduce-for-anyway#comment3http://ayende.com/4436/what-is-map-reduce-for-anyway#comment3Tue, 16 Mar 2010 09:05:56 GMTThere is a good paper on this, covering the problem of merging, and Quoting from the paper: "This new Map-Reduce-Merge programming model retains Map-Reduce’s many great features, while adding relational algebra to the list of database principles it upholds. It also contains several configurable components that enable many data-processing patterns." Google "Map-reduce-merge: simplified relational data processing on large clusters " for details. Its agood read! http://ayende.com/4436/what-is-map-reduce-for-anyway#comment2http://ayende.com/4436/what-is-map-reduce-for-anyway#comment2Tue, 16 Mar 2010 09:05:56 GMTM/R is unusable in MS windows world - the main advantage is they have cheap hardware and cheap OS (Linux). Forget it if you r .NET developer ... or use Mono :-) http://ayende.com/4436/what-is-map-reduce-for-anyway#comment1http://ayende.com/4436/what-is-map-reduce-for-anyway#comment1Mon, 15 Mar 2010 16:32:00 GMT