From owner-FreeBSD-tech-jp@jp.freebsd.org  Tue Jun  9 16:32:24 1998
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Date: Tue, 9 Jun 1998 08:30:03 +0100 (BST)
From: Doug Rabson <dfr@nlsystems.com>
To: Atsushi Furuta <furuta@sra.co.jp>
cc: mike@smith.net.au, itojun@itojun.org, core@freebsd.org,
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Subject: [FreeBSD-tech-jp 1507] Re: new config 
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On Tue, 9 Jun 1998, Atsushi Furuta wrote:

> >> In article <199806090414.VAA00467@antipodes.cdrom.com>,
> 	Mike Smith <mike@smith.net.au> writes:
> 
> > Newconfig imposes very strict hierarchical structure on the system, and 
> > whilst well-geared towards a static configuration, is much less well 
> > suited to dynamic operation (my evaluation only).  Bearing in mind that 
> > it has been at least a year since I had anything to do with newconfig, 
> > I'd be interested in more clarification.
> 
>   Please tell me your definition of "static/dynamic configuration" in
> this context.
> 
> My understanding:
> 
> 	static configuration -> to give parameters in compile time
> 	dynamic configuration -> to give parameters in boot time
> 
> Is this correct?

My understanding is that static configuration means that drivers are built
into the kernel and device instances (e.g. sio0, sio1) are fixed at
compile time.  Dynamic configuration for me means that both drivers and
device instances can be added to the system at any time.

My biggest problem with the new config system is that the device hierarchy
must be declared in full in the config file and must be matched in the
source code.  The hierarchy is encoded in two seperate places.

My dynamic configuration system which will prototype in FreeBSD/alpha does
this slightly differently.  The bus/device hierarchy grows downward from
the root as each bus probes its devices and attaches them (some of which
will be subordinate busses).  The config file currently just declares
which drivers should be compiled into the system statically.  Each driver
knows for itself which bus type it is relavent to.

--
Doug Rabson				Mail:  dfr@nlsystems.com
Nonlinear Systems Ltd.			Phone: +44 181 951 1891
					Fax:   +44 181 381 1039

