How do I interrupt R without losing all the results of the session?
Windows: If you are running under Windows you may have a problem doing an interruption that will also save your work. I am still enquiring.
Unix: According to the documentation, if you are running under Unix/Linux, go to another command window, type 'ps' to identify the process-id of the R program you want to interrupt, then type 'kill -USR1 process-id' and R should save your workspace and quit. See 'Signals' in the documentation of the 'base' package.