CFD Online Discussion Forums - constructor argList and parallel run

hi,
I have questions about the subject mentioned in the title:

1. The first part of the argList constructor is:

Code:

Foam::argList::argList

  372 (

  373     int& argc,

  374     char**& argv,

  375     bool checkArgs,

  376     bool checkOpts

  377 )

  378 :

  379     args_(argc),

  380     options_(argc)

  381 {

  382     // Check if this run is a parallel run by searching for any parallel option

  383     // If found call runPar which might filter argv

  384     for (int argI = 0; argI < argc; ++argI)

  385     {

  386         if (argv[argI][0] == '-')

  387         {

  388             const char *optionName = &argv[argI][1];

  389 

  390             if (validParOptions.found(optionName))

  391             {

  392                 parRunControl_.runPar(argc, argv);

  393                 break;

  394             }

  395         }

  396     }

...

If the first argument of argv starts with a dash (line386) and the the following string is found in the valid paralell options (line 390) method runPar() is called on parRunControl_.
Now runPar is defined as

Code:

void runPar(int& argc, char**& argv)

{

RunPar = true;  //bool RunPar;  //subobject of parRunControl

if (!Pstream::init(argc, argv))           

   {

    Info<< "Failed to start parallel run" << endl;

    Pstream::exit(1);

   }

}

and herein method init(...) out of class reference Pstream:

Code:

bool Foam::UPstream::init(int& argc, char**& argv)    //Spawns slave processes and 

                                                                             //initialises inter-communication

   36 {

   37     FatalErrorIn("UPstream::init(int& argc, char**& argv)")

   38         << "Trying to use the dummy Pstream library." << nl

   39         << "This dummy library cannot be used in parallel mode"

   40         << Foam::exit(FatalError);

   41 

   42     return false;

   43 }

Questions:
1. Method init(...) should spawn slave processes. Where is this happening in init()?
Furthermore when looking up the .C files of class UpStream on my PC I get three different files with three different init() methods. Is the method out of the online OpenFoam library the right one? How am I suppossed to know which one will be used in the code I am analysing?

2. When talking about parallel run what is meant with master process?
I have read already
http://www.openfoam.org/docs/user/ru...s-parallel.php
and
http://www.cfd-online.com/Forums/ope...g-2-2-0-a.html

If I devide the mesh into different sections and assign each section to another processor
which section or processor will be the master and more important what is the meaning of being master :D ?