!
! SINGLE MESSAGE ID LIST HEAD STRUCTURE
!
! COPY RIGHT: 
!		INLAND STEEL
!		PROCESS AUTOMATION DEPT.
!		3210 WATLING ST. MS 2-465
!		EAST CHICAGO, IN   46312
!		
! DATE OF LAST UPDATE:  13-OCT-86
!
	INTEGER MxLEN
	PARAMETER(MxLEN=44)	! SIZE OF MESSAGE ID LIST HEAD
	INTEGER MxIDSZ
	PARAMETER(MxIDSZ= 16)	! SIZE OF A SINGLE MESSAGE ID
	BYTE MIDDEF(MxLEN)
!
	BYTE MxMID(MxIDSZ)	! ASCII MESSAGE ID
	INTEGER*2 MxFLK		! FORWARD LINK TO FIRST MESSAGE IN QUEUE THIS ID
	INTEGER*2 MxBLK		! BACKWARD LINK TO LAST MESSAGE IN QUEUE THIS ID
	INTEGER*2 MxRNA		! READ BUT NOT ACK. MESG. FIRST BLOCK LINK
	INTEGER*2 MxBNA		! READ BUT NOT ACK. MESG. LAST BLOCK LINK
	INTEGER*2 MxMAX		! MAXIMUM NUMBER OF MESSAGES ALLOWED THIS ID
	INTEGER*2 MxCNT		! CURRENT NUMBER IN QUEUE THIS MESSAGE ID
	INTEGER*2 MxQSEQ	! CURRENT ON QUEUE SEQUNECE NUMBER
	INTEGER*2 MxR50(2)	! RAD 50 CONNECTED TASK NAME
	INTEGER*2 MxTCB		! TCB ADDRESS OF CONNECTED TASK NAME
	INTEGER*2 MxEFN		! READER'S EFN TO SET IF MxCNT GOES NON-ZERO
	INTEGER*2 MxNVC		! NUMBER of non-volatile message
	INTEGER*2 MxNVL		! LINK TO NEXT SCANNABLE NON-VOLATIL MESSAGE
	INTEGER*2 MxLST		! LAST BLOCK NBR OF MESSAGE LINKED TO LAST 
				!  SCANNED
C
	EQUIVALENCE(MIDDEF(1),MxMID)
	EQUIVALENCE(MIDDEF(17),MxFLK)
	EQUIVALENCE(MIDDEF(19),MxBLK)
	EQUIVALENCE(MIDDEF(21),MxRNA)
	EQUIVALENCE(MIDDEF(23),MxBNA)
	EQUIVALENCE(MIDDEF(25),MxMAX)
	EQUIVALENCE(MIDDEF(27),MxCNT)
	EQUIVALENCE(MIDDEF(29),MxQSEQ)
	EQUIVALENCE(MIDDEF(31),MxR50)
	EQUIVALENCE(MIDDEF(35),MxTCB)
	EQUIVALENCE(MIDDEF(37),MxEFN)
	EQUIVALENCE(MIDDEF(39),MxNVC)
	EQUIVALENCE(MIDDEF(41),MxNVL)
	EQUIVALENCE(MIDDEF(43),MxLST)
