Re: rtVAX300 .. adding an CPU Type..

[Matt Thomas <matt%3am-software.com@localhost>]

On Jan 3, 2013, at 2:02 PM, Holm Tiffe wrote:

> Hi,
> 
> As some of you already know I'm fiddeling around with an ISA Board
> in a PC that has an rtVAX 300 CPU on it.

The primary difference between the rtVAX and normal VAX is that the rtVAX 
requires the process page table pointers (and, hence, page table) to use 
physical address rather than system addresses.

This means all the process page tables have to be physically contiguous (as 
opposed to virtually contiguous).  Given the rapid fragmentation of physical 
memory, this makes new process creation difficult since there will rarely be 
enough physically contiguous memory available for the new process' page tables.