What is the difference between the 3 architectural components of Microsoft R Server?
RevoScaleR package &amp; ScaleR are same (I think after MS acquisition its became scaleR) 
A new file format especially designed for large files such as : 
XDF File Format (block based data format)
RxDataSource (designed to support the use of external memory algorithms with .xdf files.)
PEMA  based Algorithms
External memory implementations of the statistical algorithms most commonly used with large data sets such as : rxSummary, rxCrossTabs, rxLinMod. rxKMeans, rxGlm etc.
An extensible programming framework that allows R programmers to write their own external memory algorithms that can take advantage of ScaleR Enterprise’s new Big Data capabilities.

DistributedR for supporting big data framework
ConnectR It has all connectors to interact with other data sources
DeployR is used to integrate R with any application programming