Installers' Note                                            Appendix A

		       Interface Source Changes
		       Tektronix 4010 Interface

This interface is suitable for most Tektronix graphics terminals and
emulators, including 4010, 4014, 4107 and 4208.

You may wish to modify the following to suit your local environment:

(a) J06WDF

    In the Tektronix 4010 NAG Graphical Interface the user may be
    prompted when the frame advance routine is invoked; this is to
    prevent output to the terminal screen being erased immediately
    upon requesting a frame advance.

    In the distributed version of the interface, this is achieved by
    writing a prompt on standard output, and waiting for a response on
    standard input. Should you wish to change the method of prompting,
    then you must modify the following lines of code:

      C
      C     Pause until input received
      C
	    IF (PAUSE) THEN
	       WRITE (*,FMT=*) 'PRESS <CR> TO CONTINUE'
	       READ (*,FMT=*)
	    END IF

(b) J06XAF

    The default NAG pen values for this interface are defined in the
    INTEGER array NGPEN. These may be redefined by modifying the
    following piece of code:

      C
      C     Set up default set of four NAG pens (BJ06XA)
      C
	    DO 20 I = 1, 4
	       IF (KERMIT) THEN
		  NGPEN(I,1) = I
	       ELSE
		  NGPEN(I,1) = 1
	       END IF
	       NGPEN(I,2) = I
	       NGPEN(I,3) = I
	 20 CONTINUE

(c) J06YAT

    This routine calls the Fortran bitwise boolean AND operation,
    which is defined in the Fortran Military Standard (MIL-STD-1753).

    If your Fortran compiler does not allow the use of the Fortran
    Military Standard routine IAND, then you may use the alternative
    version of J06YAT which is supplied with this interface
    (j06yat.f.mil).

(c) J06YAU

    This routine calls the Fortran bitwise boolean SHIFT operation, 
    which is defined in the Fortran Military Standard (MIL-STD-1753).

    If your Fortran compiler does not allow the use of the Fortran
    Military Standard routine ISHFT, then you may use the alternative
    version of J06YAU which is supplied with this interface
    (j06yau.f.mil).

(d) J06YCS

    This routine calls the Fortran bitwise boolean OR operation, 
    which is defined in the Fortran Military Standard (MIL-STD-1753).

    If your Fortran compiler does not allow the use of the Fortran
    Military Standard routine IOR, then you may use the alternative
    version of J06YCS which is supplied with this interface
    (j06ycs.f.mil).

(e) J06YCT

    Depending on the file type assigned to the current command
    sequence channel the first character on a line may be taken as a
    Fortran control character. In these cases you should ensure that a
    blank character is output as the first character on each line of
    UNIX plot output. This may be achieved by amending the statement 

      WRITE (NCOM,FMT='(A,A1)') OUT(1:NCHAR), 't'

    to read 

      WRITE (NCOM,FMT='(A1,A,A1)') ' ', OUT(1:NCHAR), 't'

(f) J06YCW

    Depending on the file type assigned to the current command
    sequence channel the first character on a line may be taken as a
    Fortran control character. In these cases you should ensure that a
    blank character is output as the first character on each line of
    Tektronix output. This may be achieved by amending the statement 

      WRITE (NCOM,FMT='(A)') OUT(1:NCHAR)

    to read 

      WRITE (NCOM,FMT='(A1,A)') ' ', OUT(1:NCHAR)

===================================================================
    Copyright The Numerical Algorithms Group Ltd, U.K., 1994
    Developed by D.J. Adams of the Computing Services,
                 University of Southampton.