PARAMETER	RWV=0, RWL=1, RWHB=2, RWHD=3
	INTEGER*2	BLKTYP,BUFF(256)
	LOGICAL*1	BUFFB(512)
	INTEGER*2	BLKNH,BLKNL
	INTEGER*2	BLKN(2)
	EQUIVALENCE	(BLKN(1),BLKNH),(BLKN(2),BLKNL)
	EQUIVALENCE	(BUFF(1),BUFFB(1))
	COMMON /BUFCOM/BLKTYP,BLKN,BUFF