INT 61 - Atari Portfolio - DETERMINE CCM VALIDITY                               
	AH = 0Bh
	AL = drive number (00h = A:,01h = B:)
Return: CF clear if successful (card present and correct)
	CF set on error
	    AH = error code (see #00234 at INT 13/AH=01h)
SeeAlso: AH=00h"Portfolio",AH=07h"Portfolio",AH=0Dh"Portfolio"