Subject: Re: An approach for detachable interfaces.
To: Bill Sommerfeld <>
From: Christian E. Hopps <>
List: tech-net
Date: 11/06/1999 01:58:53
Bill Sommerfeld <> writes:

> > I said weird, because the whole notion of "remove a device, but have
> > the kernel pretend some aspects of the device are still there," is
> > just plain weird.  If a device is gone, it should be gone completely
> > from the kernel. 
> This is an interesting assertion to make; everything else you say
> follows from it, but I'm not convinced that this should always be true
> for every single subsystem. 

While I think your idea leads to some nifty results, I tend to agree
with Chris here.  If I remove a device it should go away.  If I just
want carrier loss I'll remove the ethernet plug.  If I just want to down 
the interface I'll ifconfig it down.

I think the potential for confusing people or just plain doing the wrong 
thing in certain circumstances is too high with your method.

If you really want to treat a removal as temporary (i.e., keep state
around for the removed device), and you don't want to confuse people or
DTWT, you really have to restrict re-use of that state to the original
hardware only.  I think this is what Jonathan was getting at.