INT 67 - VIDEMS.SYS v1.31+ - RETURN HIDDEN BLOCK SIZE AX = 2763h CL = 04h BX = signature AAFFh Return: AH = 00h if successful DX = block size in kilobytes Desc: Returns the amount of EMS which can be safely used at any time, and can't be destroyed by writing anything to the B800:0000 buffer. Note: this function normally returns 184K, while the driver provides up to 240K of EMS. SeeAlso: AX=2763h/CL=01h,AX=2763h/CL=02h