INT 2F U - IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. ROM-DOS v4.0 - INSTALLATION CHECK AX = 1980h Return: AL = FFh if ??? installed/supported Note: called at the very beginning of SHELLSTB.COM, which exits if AL is not FFh on return SeeAlso: AX=1981h,AX=1982h