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)