Subject: Re: devfs, was Re: ptyfs fully working now...
To: Christos Zoulas <>
From: Bill Studenmund <>
List: tech-kern
Date: 11/13/2004 00:27:42
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On Fri, Nov 12, 2004 at 10:31:22PM -0500, Christos Zoulas wrote:
> On Nov 12, 10:18pm, ("Steven M. Bellovin") wrote:
> -- Subject: Re: devfs, was Re: ptyfs fully working now...
> | I haven't thought through all the details (and I'm more than slightly=
> | fried from being at the IETF all week), so there are probably plenty of=
> | other holes I've missed.  But I think my first question stands: what=20
> | problem does devfs solve?
> As you mentioned:
> 1. keeps /dev from being cluttered with non-existent nodes.
> 2. avoids the problem of having to create new nodes when devices appear
>    and deletes nodes when devices dissappear.
> 3. userland does not have to know about device major and minor numbers
>    anymore like MAKEDEV does.

But userland still does care about device major and minor numbers in the=20
scheme you mentioned. Less than before, but it still cares. Well, the=20
system (kernel and userland) care that device numbers (major/minor tuple)=
are constant between boot, so that on the next boot the devfs log will=20
refer to the same devices as the last boot.

Take care,


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