Re: Mounting a in-ROM filesystem efficiently

[Richard B. Johnson]

On Fri, 14 Dec 2001, Dominik Kubla wrote:

> On Thu, Dec 13, 2001 at 01:34:45PM -0500, Richard B. Johnson wrote:
> > 
> > Well RAM is a hell of a lot cheaper than NVRAM. If you don't have
> > the required RAM on your box, the hardware engineers screwed up
> > and have to be "educated" preferably with an axe in the parking-lot.
> > 
> 
> What about security issues?  I can imagine quite a few scenarios where
> you would want to insure that you run untampered binaries. (eg. use
> ROM instead of the usual CD-ROM or read-only FD to run your security
> critical application.)
> 

I never even implied that you would run CD-ROM or FD in embedded
applications. The stuff that runs comes-from ROM, actually NVRAM so
in can be written/updated in production. However, EIP software
(Execute In Place) has always been a dog and, even Ethernet switches
3COM, Cisco, etc., don't run that way. You need to get the stuff
that runs into RAM.

Security isn't a problem with embedded systems because everything
that could possibly be done is handled with a "monitor". There is
no shell. If there is no way to execute some foreign executable,
you don't have a security issue unless some dumb alleged software
engineer added some back-doors to the monitor.

Cheers,
Dick Johnson

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