[cap-talk] Midori in The Register

[Kenneth Hamer-Hodges]

Adding a second DMA version of typed hardware leads to a second set of
mechanism at risk and question about delegation to the DMA level open up
another Pandora's Box. 
With multi core solution so easily available today this simplicity and
uniformity remain the best option for building a Trusted Computer Base.
k

> -----Original Message-----
> From: cap-talk-bounces at mail.eros-os.org [mailto:cap-talk-
> bounces at mail.eros-os.org] On Behalf Of Jonathan S. Shapiro
> Sent: Wednesday, August 06, 2008 9:49 AM
> To: General discussions concerning capability systems.
> Subject: Re: [cap-talk] Midori in The Register
> 
> On Wed, 2008-08-06 at 06:32 -0400, Kenneth Hamer-Hodges wrote:
> > Plessey 250 system rejected ... any hardware DMA.
> > The multiprocessor architecture used any of the multiple CPUs to perform
> I/O
> > actions directly by a thread with the requisite "capability".
> 
> I think it's clear in hindsight that this was a bad call. If nothing
> else, dedicating a CPU to data motion is a wasteful use of resource. An
> alternative would be to implement a typed DMA mechanism at the hardware
> interface. This would admit the possibility of a safe hardware DMA
> subsystem, the remaining problem being the requirement to perform a safe
> join following DMA completion.
> 
> 
> shap
> 
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