The following table lists DMA channel assignments that are used by legacy ISA devices and are therefore considered fixed.
Legacy ISA DMA Considered Fixed
Hardware DMA
System function (default)
DMA 0
ISA expansion
DMA 1
—
DMA 2
FDC
DMA 3
extended capabilities port (ECP) parallel port on LPT 1
DMA 4
DMA controller cascading
DMA 5
—
DMA 6
—
DMA 7
—