Each Fortran line has the following four fields:

    Statement label field           Columns 1-5
    Continuation indicator field    Column 6
    Statement field                 Columns 7-72 (if you specify
                                      the EXTEND_SOURCE compiler
                                      option or OPTIONS/EXTEND_SOURCE,
                                      statements extend to column 132)
    Sequence number field           Columns 73-80

  Note:  If you use the sequence number field, do not use tabs
  anywhere in the source line, or the compiler may interpret the
  sequence numbers as part of the statement field in your program.

1  –  Fixed

  A Fortran line is divided into fields for the required information.
  Each column represents a single character.

   COLUMN    FIELD
   ------    -----
       1     Indicator: Comment(C,c,*,!,blank) or Debug(D,d)
     1-5     Label (any decimal integer except zero)
       6     Indicator: Continuation of statement (any character
                   except zero or space)
    7-72     Statement Field (up to column 72)
   73-80     Sequence Number (optionally to column 132 -- ignored)

                                 NOTE

          This source format is obsolescent  in  Fortran  95.
          HP  Fortran  flags  obsolescent  features,  but
          fully supports them.

2  –  Tab

  A Fortran line is divided into fields for the required information.
  Each column represents a single character.  You cannot specify a
  sequence number field using this method of coding.

   COLUMN   FIELD
   ------   -----
   (before tab)
     1      Indicator: Comment(C,c,*,!,blank) or Debug(D,d)
   1-5      Label (any decimal integer except zero)
   (after first tab)
     6      Indicator: Continuation of statement (any digit 1-9)
   (after second tab)
            Statement Field (up to column 72)

  Tabs are treated as single characters.