QNX 6.5 apparently maps first 256MB of physical memory into kernel space at fixed location. Also I believe that QNX's kernel memory contains region that maps to

QNX 6.5 apparently maps first 256MB of physical memory into kernel space at fixed location. Also I believe that QNX's kernel memory contains region that maps to pages of user space memory of other processes (as part of the message passing mechanism, but I'm not exactly sure that I understand correctly how it actually works).