Int 21 Fn 30  - Phar Lap 386/dos-extender, Intel Code Builder - Installat  [E]

   AH = 30h
   EAX = 00003000h
   EBX = 50484152h ("PHAR")

Return: AL = major DOS version
   AH = minor DOS version
   EAX bits 31-16 = 4458h ('DX') if 386/DOS-extender installed
       BL = ASCII major version number
   EAX bits 31-16 = 4243h ('BC') if Intel Code Builder installed
       EDX = address of GDA

See Also: AX=2501h,AX=FF00h,INT 2F/AX=F100h