Bitfields for device attributes (character device):
Bit(s)	Description	)
 15	set (indicates character device)
 14	IOCTL supported (see AH=44h)
 13	(DOS 3.0+) output until busy supported
 12	reserved
 11	(DOS 3.0+) OPEN/CLOSE/RemMedia calls supported
 10-8	reserved
 7	(DOS 5.0+) Generic IOCTL check call supported (driver command 19h)
	(see AX=4410h,AX=4411h)
 6	(DOS 3.2+) Generic IOCTL call supported (driver command 13h)
	(see AX=440Ch,AX=440Dh"DOS 3.2+")
 5	reserved
 4	device is special (use INT 29 "fast console output")
 3	device is CLOCK$ (all reads/writes use transfer record described
	  below)
 2	device is NUL
 1	device is standard output
 0	device is standard input
Note:	for European MS-DOS 4.0, bit 11 also indicates that bits 8-6 contain a
	  version code (000 = DOS 3.0,3.1; 001 = DOS 3.2;
	  010 = European DOS 4.0)
SeeAlso: #01648,#01646