For detailed parallelization, referring to Beyond single core R.

For a no-computer background R user, it is hard to comprehend some terms of hardware and software.

Hardware terms

• Node: A single motherboard with multiple sockets.
• Processor/Socket: the silicon containing multiple cores.
• Core: the unit of computation.
• Pseudo-cores: can appear to the OS as multiple cores.

Software terms

Interpreted languages generally can only directly work with processes. You can call libraries that invoke threads (BLAS/LAPACK)

• Process: data and code in memory.
• One or more threads of execution within a process.
• Threads in the same process can see most of the same memory.
• Processes generally can not peer into another processes memory.

The R parallel packages

• parallel: incorporates two pacakges below.
• multicore: forking, for using all processors on a single processor.
• snow: spawning, for using any group of processors, possibly across a cluster.

parallel package