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. - SCATTER/GATHER LOCK REGION
	AX = 8105h
	DX = flags (see #03224)
	ES:DI -> Extended DMAsee Direct Memory Access descriptor structure (see #03222,#03223)
		  region size, linear segment, linear offset, and number avail
		  fields set
Return: CF clear if successful
	    EDDS number used field set
	    if DX bit 6 set, lower 12 bits of BX = offset in first page
	CF set on error
	    AL = error code (see #03218)
	    EDDS region size field filled with max length in bytes that can be
		  locked and described in the EDDS table
BUG:	Windows 3.0 in enhanced mode may return zero instead of the physical
	  page address for pages which were originally not present
SeeAlso: AX=8103h,AX=8106h


Bitfields for VDSsee Virtual DMA Specification flags:
Bit(s)	Description	(Table 03224)
 0-5	reserved (zero)
 6	EDDS should be returned with page table entries
 7	only present pages should be locked (not-present pages receive entry
	  of 0000h)
 8-15	reserved (zero)