In a computer system the typically high overhead requirement for CPU instructions to operate a conventional direct memory access (DMA) controller are reduced to two user-level memory references via User-level Direct Memory Access (UDMA). The UDMA apparatus is located between the CPU and a DMA Controller,...http://www.google.ca/patents/US5659798?utm_source=gb-gplus-sharePatent US5659798 - Method and system for initiating and loading DMA controller registers by using user-level programs
