CRT Unit
                          Input and Output files


     The CRT unit reassigns the Input and Output standard text files to
     refer to the CRT.  This corresponds to the code:

                              AssignCRT(Input);
                              ReSet(Input);
                              AssignCRT(Output);
                              ReWrite(Output);

     This effectively disables I/O redirection of the Input and Output files.
     In order to regain the ability, you would have to reassign the Input
     and Output files by executing:

                              Assign(Input,'');
                              ReSet(Input);
                              Assign(Output,'');
                              ReWrite(Output);