title: Where does allocated PCI memory reside?
body: <p>Probably a super basic question, however I was reading this: <a href="http://www.tldp.org/LDP/tlk/dd/pci.html" rel="nofollow">http://www.tldp.org/LDP/tlk/dd/pci.html</a> and I was curious, when I write to a PCI memory space address, exactly what am I writing to?</p>
  
  <p>Am I writing to memory modules on the PCI device? A special sub-section of my system's memory? Memory attached to the mainboard specifically for the use of the PCI bus? Is it completely architecture dependent and intentionally left vague?</p>