INT 21 - CTask 2.0+ - INSTALLATION CHECK
AX = 3000h
BX = 1234h
DS:DX -> 8-byte version string (DX < FFF0h) "CTask21",00h for v2.1-2.2
Return: AL = DOS major version
AH = DOS minor version
CX:BX -> Ctask global data block
Notes:  if first eight bytes of returned data block equal eight bytes passed
in, CTask is resident
CTask is a multitasking kernel for C written by Thomas Wagner


213000BX1234 - CTask 2.0+ - INSTALLATION CHECK