VMS Help PASCAL, Input Output, Direct Access, LOCATE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The  LOCATE  procedure  positions  a  random-access  file  at  a
  particular  component  so that the next PUT procedure can modify
  that component.

  Syntax:

     LOCATE( file_variable, component-number
        [[, ERROR := error-recovery]] );

  The 'file_variable' is the name of the file variable  associated
  with the file to be positioned.

  The  'component-number'  is  a   positive   integer   expression
  indicating  the relative component number of the component to be
  found.

  The 'error-recovery' specifies the action  to  be  taken  if  an
  error occurs during execution of the routine.  By default, after
  the first error, the error message is printed and  execution  is
  stopped.

  The file can be in any mode before LOCATE is called.   The  mode
  is set to generation after the procedure's execution.

  The LOCATE procedure positions the file so  that  the  next  PUT
  procedure  writes  the  contents  of  the  file  buffer into the
  selected  component.   After  LOCATE  has  been  performed,  UFB
  returns TRUE and EOF is undefined.

  See the "Compaq Pascal Language Reference Manual"  for  complete
  information on the LOCATE procedure.