Function:     IRTP_SA2BPHF

Purpose:      IRTP_SA2BPHF returns the BPHF tape name containing a SOP/ATT

Category:     TAPE

File:	      ir_tapes.c

Author:       P.R. Roelfsema

Use:	      INTEGER IRTP_SA2BPHF( SOP        ,   Input   integer
				    ATT        ,   Input   integer
				    DIRECTORY  ,   Output  character*(>35)
				    FILENO     )   Output  integer

	      IRTP_SA2BPHF Error return code:
			   >0 - no problem.
			   -5 - SOP/ATT not found.
			   -6 - tape descriptor file not found
			   -7 - string DIRECTORY too small
	      SOP	  SOP of desired BPHF data.
	      ATT	  ATT of desired BPHF data.
	      DIRECTORY   The name of the tape containing BPHF data for
			  the SOP/ATT combination (>35 chars).
	      FILENO	  The sequential file number of the file on
			  TAPENAME containing the BPHF for SOP/ATT.

Updates:      Sep.  5, 1990: PRR, Creation date
	      Jun. 20, 1991: PRR, Patch to use new filesystem
	      Nov.  7, 1991: AdJ, Corrected hard-coded (!) filename
	      Dec.  3, 1991: PRR, Added IRAS_ROOT.