Subject: Re: Another changer, another changer problem
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: John Nemeth <>
List: current-users
Date: 10/10/1998 16:20:35
On Oct 4,  9:08am, der Mouse wrote:
} Subject: Re: Another changer, another changer problem
} > The basic idea that is that if somebody does "mount -l <label>:x"
} > then the mount program would look at all the incore disklabels
} Hold it right there.  How would it find them?  Would you try to guess

     Okay, so my idea needs to be fleshed out a bit.

} which /dev entries correspnod to disks, or would you add a new

     This is one possibility since there are a limited number of /dev
entries that generally correspond to disks, primarily:  sd, wd, xy,
cd, and mcd.  However, this method does have scalability problems
since it's hardcoded.

} interface that would allow mount to query the kernel about all disk
} devices?  And if the latter, how do you propose that the kernel tell
} which devices are disks?

    This is possible using the suggested /kern entry.  Of course this
means that to use this feature you would have to mount /kern and that
it couldn't be used for the root disk.

     Somebody has mentioned that there already is a list of disks in
the kernel and we just need to dig through kmem to find it, which
would fit in with the NetBSD way of doing things.

} > The beauty of this method is that it is simple and does pretty much
} > everything that everybody wants.  [...]
} If the "how to find all disks" issue is addressed, I agree with the
} rest of what you say.

     Yeah, we seem to be coming to a consensus on this particular
item.  It's good to see that something positive is coming out of this

     Personally, I probably won't use this feature, so I don't care
that much.  I just threw out my ideas for discussion.  But, if
implemented the way I suggested, it won't have any impact on the
system, so it won't bother me.  Things that bloat the kernel
unnecessarily do bother me.

}-- End of excerpt from der Mouse