1. A method for emulating an industry standard architecture direct memory access controller (ISA-DMAC) and its bus resources with a peripheral component interconnect direct memory access controller (PCI-DMAC) and its bus resources, comprising the steps of: write snooping a PCI-bus processor accessing a PCI-bus for access attempts to an ISA-DMAC register; copying any register values detected in the step of write snooping to a corresponding register in a PCI-DMAC; performing a direct memory access operation commanded by said PCI-bus processor of the ISA-DMAC with said PCI-DMAC in the PCI-bus resource space; updating a corresponding register in said PCI-DMAC with a result value for said direct memory access operation; and writing back and updating a corresponding ISA-DMAC register with a result value for said direct memory access operation; wherein, a software program executing on said PCI-bus processor that expects an ISA-DMAC and its corresponding ISA-bus resources to be present will be satisfied that any direct memory access operations that it has apparently initiated on said ISA-bus were responded to and provided appropriate results.