Subject: Re: /rescue, crunchgen'ed?
To: Johnny Billquist <>
From: Richard Earnshaw <>
List: current-users
Date: 08/30/2002 13:49:06
> On Fri, 30 Aug 2002, Richard Earnshaw wrote:
> > > Johnny Billquist wrote:
> > > > A big danger is accidental overwriting.
> > > Overwriting of /rescue? Uhm...
> > > Yes, that's possible.
> > > 
> > 
> > So is overwriting of /bin/sh with /bin/rm.
> > 
> > These are all rather pointless mind games, they don't really make anything 
> > more or less safe.
> You are oversimplifying things. I'm not talking about stupid user
> overwriting a file with something else (even though that, too, is a
> possibility). I'm talking about corrupt file systems, which individual
> blocks within a file might be overwritten.
> And in both cases, two different files are more robust than a single
> file. It's the same story as with everything depending on libc at runtime
> (or any other single point of failure).
> If you don't agree that a single point of failure makes things less safe
> I'm sure NASA would be interested in hearing about your deductive
> skills. :-)

What makes you think that having lots of separate programs, each of which 
does different things and cannot represent the functionality of another 
isn't a single point of failure?

As has been pointed out.  If you are worried about things like that. Then 
install several /rescue directories.  Better still, do that on several 
different disks, and arrange your system so that you can boot from any of 
them in an emergency.

Now that is a practical approach to introducing redundancy, not a 
half-hearted one.