Last week, Microsoft quietly made available to its MSDN and DreamSpark subscribers its R Server family of products.

On January 12, Microsoft announced officially the availability and rebranding of the Revolution R Enterprise line as "Microsoft R Server" Company officials also said for the record that Revolution R Open is now called "Microsoft R Open" and available as a free download.

R is a programming language that can be used in big-data statistics, predictive modeling and machine learning . Microsoft last April completed its acquisition of Revolution Analytics, the maker of a distribution of the R programming language for statistical computing and predictive analytics, for an undisclosed amount.Microsoft execs also announced today there is a new Microsoft R Server Developer Edition product available today as a free download. This version, which includes "all the features of the commercial version" of R Server is available to developers, data scientists and database administrators. Update: The free developer version looks to be available by signing up with a Microsoft Account to the Visual Studio Dev Essentials program.

The developer version of R is for testing, development and creation of R scripts and models. There are no limitations on the Server software regarding size of the org or types of apps, but it can only be used in a testing and development environment, a Microsoft spokesperson said. The previously announced Microsoft Data Science Virtual Machine will come with a preinstalled and preconfigured version of the Microsoft R Server Developer Edition product.

The Microsoft R Server line-up includes:

Microsoft R Server for Hadoop on Red Hat

Microsoft R Server for Teradata DB

Microsoft R Server for Red Hat Linux

Microsoft R Server for SuSE Linux

RRE, or Revolution R Enterprise, for Windows Read this Hadoop big data analytics: Can SQL support bring it to the masses? For businesses that want to run analytics on low-cost Hadoop clusters, fully compliant SQL is now possible natively on the big data platform, according to Actian. Read More

As Microsoft previously announced, the company is integrating the commercial R distribution into SQL Server 2016 in the form of SQL Server R Services. Until SQL Server 2016 is released, Revolution R Enterprise for Windows will remain available as a standalone product, officials said today.

Microsoft is continuing its work to integrate R into Azure HDInsight (Hadoop on Azure) and Azure Machine Learning. It also plans to deliver R Server as virtual machine available via the Azure Marketplace. And according to today's blog post, Microsoft also is working on R Tools for Visual Studio (RTVS), an offering similar to its Python Tools for Visual Studio (PTVS).

Update: What's the deal on pricing for R Server (for the versions that aren't free)? A spokesperson sent the following statement:

"Pricing will vary depending on volumes and types of agreements customers use. Pricing for the Linux versions of Microsoft R Server are in line with the SQL Server 2014 Enterprise cores. For more information contact your local Microsoft Account Team or Microsoft Reseller for more information."