.TITLE ALLOCTAPE  ALLOCATE MTA0 TO THE NULL PROCESS
	$UCBDEF		;DEFINE UCB OFFSETS
	$CCBDEF		;DEFINE CCB OFFSETS
START::	.WORD	0
	$ASSIGN_S	DEVNAM=DEVICE,CHAN=CHANNEL
	BLBC	R0,NOGO		;JUNK IT IF ASSIGN FAILS
	$CMKRNL_S	GET_UCB		;CHANGE MODE TO KERNAL
	$DASSGN_S	CHAN=CHANNEL	;DEASSIGN THE CHANNEL
	$CMKRNL_S	ALL_UCB		;ALLOCATE THE MAG TAPE
NOGO:	RET				;ALL DONE
GET_UCB:	.WORD	^M<R2,R3,R4,R5>
	JSB	@#IOC$VERIFYCHAN	;GET THE CCB IN R1
	MOVL	CCB$L_UCB(R1),UCBADR	;MOVE THE UCB TO STORAGE
	RET				;GO BACK IN USER MODE
ALL_UCB:	.WORD	0
	MOVL	UCBADR,R0
	DSBINT	#31		;DISABLE ALL INTERRUPTS
	BISL	#DEV$M_ALL,UCB$L_DEVCHAR(R0)	;SET DEVICE AS ALLOCATED
	MOVL	#^X10000,UCB$L_PID(R0)	;SET OWNER TO NULL PROCESS
	ENBINT		;RE ENABLE INTERRUPTS
	RET		;THAT IS ALL
;
CHANNEL:	.LONG	0
DEVICE:	.LONG	DEVE-DEV
	.LONG	DEV
DEV:	.ASCII	/_MTA0:/
DEVE:
UCBADR:	.LONG	0
	.END	START