19.1  Direct DMA Window Changes

  There are changes planned for the usage of the Direct DMA
  window for PCI drivers starting in OpenVMS Alpha 7.2.
  These changes were required to support the Galaxy Software
  architecture on OpenVMS and memory holes.  The change
  involves moving the Direct DMA window away from physi-
  cal memory location 0.  This document should provide enough
  background and information for you to update your driver.

  Note that this document doesn't talk about bus addressable
  pool (BAP).