Nvidia IA32 User Manual page 80

DMA Channel 0,1,3,5,6,7
DMA Channel PCI/PMP functions. The options: [Available], [Reserved].
Reserved Memory Size
Set up the size of memory block to reserve for legacy ISA devices.
The options: [Disabled], [16 K], [32 K], [64 K].
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IA32 Motherboard User Manual