Re: rtVAX300 .. adding an CPU Type..

[Dave McGuire <mcguire%neurotica.com@localhost>]

On 01/03/2013 06:06 PM, Matt Thomas wrote:
>> 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.

  Not the rtVAX-300.  The -300 is a little module with a bog-standard
CVAX chip, an SGEC, and some flash chips for a bootstrap on it.

  Here's one, socketed, on a 6U VME board:

  http://www.neurotica.com/misc/rtVAX-300-1.jpg
  http://www.neurotica.com/misc/rtVAX-300-2.jpg

                 -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA