Subroutine SelDev(Lun)
	BYTE BNAME(40)
C
C	Show the device numbers and their names and ask for
C	a device number. Attempt to select that device. If
C	not successful, display an error message and ask for
C	a new device number.
C
	EXTERNAL LEN
C
C	Display device numbers and names.
C
	Type 91
91	FORMAT(/)
	IDEV = 1
110		CALL GSDNAM(IDEV,BNAME)
		L = LEN(BNAME)
		IF (L .EQ. 0) GO TO 120
		TYPE 111, IDEV, (BNAME(I), I=1,L)
111		FORMAT(' Device ',I2,' is ',40A1)
		IDEV = IDEV + 1
		GO TO 110
120	CONTINUE

C	Ask for a device number.

	Type 91
5	TYPE 121
121	FORMAT('$Graphics device number? ')
	ACCEPT 122, IDEV
122	FORMAT(I5)

C	Select that device.

	CALL DEVSEL(IDEV,Lun,IERR)

	IF (IERR .EQ. 0) GO TO 200

	TYPE 131
131	FORMAT(' That device is not available at this time!')
	GO TO 5

200	Continue

	Return
	END