INT 4B - Virtual DMA SpecificationA set of interrupt calls which permit the use of DMA even on systems running in protected or Virtual-86 mode with their address remapping, or systems such as Micro Channel PSIBM PS/2, any model/2s with multiple bus masters independently performing DMA operations. - REQUEST DMAsee Direct Memory Access BUFFER
	AX = 8107h
	DX = flags
	    bit 0: reserved (zero)
	    bit 1: data should be copied into buffer
	    bits  2-15 reserved (zero)
	ES:DI -> DMAsee Direct Memory Access descriptor structure (see #03221) with region size set
		  (also region offset and region segment if DX bit 1 set)
Return: CF clear if successful
	    DDS physical address and buffer ID set
	    DDS region size filled with length of buffer
	CF set on error
	    AL = error code (see #03218)
SeeAlso: AX=8108h