INT 21 - DR-DOS 3.41+ - DETERMINE DOS TYPE/GET DR-DOS VERSION
AX = 4452h
CF set
Return: CF set if not DR-DOS
AX = error code (see AH=59h)
CF clear if DR-DOS
DX = AX = version code
AH = single-tasking/multitasking
10h single-tasking
AL = operating system version ID
60h DOS Plus
63h DR-DOS 3.41
64h DR-DOS 3.42
65h DR-DOS 5.00
67h DR-DOS 6.00
14h multitasking
AL = operating system version ID (see AX=4451h)
Notes:  the DR-DOS version is stored in the environment variable VER
use this function if looking for single-tasking capabilities, AX=4451h
if looking for multitasking; this call should never return multi-
tasking values
SeeAlso: AX=4451h,AX=4459h

See also: 214412

214452 - DR-DOS 3.41+ - DETERMINE DOS TYPE/GET DR-DOS VERSION