This book does not cover Direct Memory Access (DMA) in detail. However, NT 3.51 and NT 4 driver writers will find that they must access the DMA system routines in a new way. All the same routines are there, you just have to call IoGetDmaAdapter first. This returns a pointer to a DMA_ADAPTER object. The DmaOperations field in there contains pointers to all the familiar routines. Call the DmaOperations PutDmaAdapter callback when you have finished with the DMA_ADAPTER object.

Table C.1 shows the corresponding old and new routines. Just to reiterate, there is no kernel routine directly called PutDmaAdapter. This routine is only available through the DMA_ADAPTER structure, e.g.,

(*DmaAdapter->DmaOperations->PutDmaAdapter)(DmaAdapter);