What is the relation between RStudio and RServe?

Question 1

Rserve is a client server implemenation written in pure c that starts a server and spawns multiple processes each with it's own R workspace. This is not threads but processes due to R's limitation on multithreading. It uses a QAP packing protocol as it's primary form of transport between the client and the server. You execute commands via the client (PHP, Java, C++) to the server and it returns you REXP objects that are essentially mappings to R's underlying SEXP data objects. Rserve also offers a websockets version that does will can transmit data through websockets but the api is not well documented. It also supports basic authentication through a configuration file.

Rstudio is a C++ and gwt application that provides a web based front end to R. AFAIK it uses json as it's primary transport and supports authentication through pam. Each user has a workspace configured in their home directory. It runs a server very similar but not the same as Rserve to communicate with R using RCPP. It also has it's own plotting driver used to wrap the plot device so that it can pickup the plots to be served to the ui. It has much more functionality such as stepping through your code from the ui and viewing workspace variables.

Functionally they are similar in that they provide a client/server connection to R but IMHO the comparison stops there.

Question 2

I believe they are separate projects (though I could be wrong). I've never heard of RServe and there does not appear to be any mention of it in the documentation for RStudio. I have used and would recommend RStudio Server. It is relatively easy to set up and super easy to use once it is set up. This is a helpful guide to setting up a server on Amazon EC2:

#Create a user, home directory and set password
sudo useradd rstudio
sudo mkdir /home/rstudio
sudo passwd rstudio
#Enter Password
sudo chmod -R 0777 /home/rstudio

#Update all files from the default state
sudo apt-get update
sudo apt-get upgrade


#Be Able to get R 3.0
sudo add-apt-repository 'deb http://cran.rstudio.com/bin/linux/ubuntu precise/'

#Update files to use CRAN mirror
#Don't worry about error message
sudo apt-get update

#Install latest version of R
#Install without verification
sudo apt-get install r-base

#Install a few background files
sudo apt-get install gdebi-core
sudo apt-get install libapparmor1

#Change to a writeable directory
#Download & Install RStudio Server
cd /tmp
wget http://download2.rstudio.org/rstudio-server-0.97.551-amd64.deb
sudo gdebi rstudio-server-0.97.551-amd64.deb
#Once you’ve installed the above commands, you can now access RStudio through your local browser. Navigate to the Public DNS of your image on port 8787, similar to:

#http://ec2-50-19-18-120.compute-1.amazonaws.com:8787

Question 3

The earlier answer about 3 years old provide old information, such as here.

Updated correction

RStudio is a firm that provides the open source RStudio IDE for R. They also sell commercial services such as RStudio Server Pro that markets itself with load balancing and related things. Apparently, the successuful open source project has lead the way to markets.

Question 4

You may also mean Microsoft R Server, which is now called Microsoft Machine Learning Server?

There is also RServer by RStudio.

Anyway how to install both can be found here.