History

 The 'history' is a value that indicates whether the file  exists
 or  if  VSI Pascal must create the file.  If you specify OLD and
 if VSI Pascal cannot find the file, an  error  occurs.   If  you
 specify  READONLY,  you  can  only  read  from  the file; if you
 attempt to write to the file, an error occurs.  If  you  specify
 UNKNOWN, VSI Pascal looks for an existing file but creates a new
 file if there is no  existing  file.   If  you  specify  OLD  or
 UNKNOWN  and  if  the  attempt to open the file generates a file
 protection error, VSI Pascal tries again using READONLY.

 NEW is the default for OPEN/REWRITE openings, while OLD  is  the
 default for EXTEND/RESET openings.