Subject: Re: [README] MI device major assignment
To: Bill Studenmund <wrstuden@netbsd.org>
From: Jaromir Dolecek <jdolecek@netbsd.org>
List: tech-kern
Date: 10/09/2003 15:24:15
Bill Studenmund wrote:
> >   |   | and that this would avoid major mapping problems for emulations
> >   |   | which use 8bit majors.
> 
> Is it? Mapping is a table lookup each way (to/from emulation) isn't it? 
> All this does is make emul -> NetBSD entries grow ot 16 bits, and add 
> slots to the NetBSD -> emul table.
> 
> I'm not sure what happens when we have more than 256 majors we want the 
> enulation to see. :-)

Besides several special devices for some of emulations, we generally
don't do any major number translation for emulations. We just pass it
along as opaque value. So it's better to prefer 8bit values, which
all emulations are prepared to handle. This would need to be
reevaluated once we'd have more than 256 allocated majors, but should
be fine until then.

Jaromir
-- 
Jaromir Dolecek <jdolecek@NetBSD.org>            http://www.NetBSD.cz/
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