Re: revivesa status 2008/07/09

[Andrew Doran <ad%netbsd.org@localhost>]

On Thu, Jul 24, 2008 at 12:31:07PM +0200, Havard Eidnes wrote:
> > > Be able to run a netbsd-4 or netbsd-3 userland on a netbsd-5 kernel.
> >
> > I've come to believe that the ABI contract we should provide is  
> > between the apps and libc/libpthread, i.e. at the .so level.  The  
> > kernel to libc/libpthread interface should be allowed to be more fluid.
> >
> > Yes, I know that this will upset people who like static libraries, but  
> > frankly, I don't really care.
> 
> That's not the only serious problem such a change would introduce.
> 
> As far as I understand it, such a change would *in practice* force a
> synchronized upgrade of both kernel and user-land (mostly due to
> "dragged-along dependencies"), as exemplified by a transition from 4.0
> to -current, to preserve full functionality.  This makes it cumbersome
> to say the least to back down of such an upgrade, if one were so
> inclined, something we've supported in the past by having the ABI
> contract between user-land and the kernel.  I think "operator-friendly
> testing of new kernels" is a feature which is important to preserve.

Speaking personally, dropping in a new kernel is not something I would ever
do on a production system. Many things would break because the compatibility
that is provided is basic.

Andrew