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 Program: CTask is a multitasking kernel for C written by Thomas Wagner Note: if first eight bytes of returned data block equal eight bytes passed in, CTask is resident