Date: Thu, 21 Mar 1996 16:07:07 +1000 From: George Scott <George.Scott@cc.monash.edu.au> To: current@freebsd.org Subject: Re: DEVFS vs "regular /dev" Message-ID: <199603210607.QAA12180@moa.cc.monash.edu.au>
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>>> This assumes that the file system abstractions currently in place >>> change as well, since the /dev FS can't be mounted *after* the / FS >>> has been mounted as an inferior FS -- >> why not? >> you don't need a mounted /dev to mount root. >> that's done specially. > > So you don't need a mounted root to have a mounted /dev, of course! > > This makes it possible to remount root r/w without unmounting the > devfs (and so still needing /dev). > >>> the /dev has to be there as >>> an overlay mount (translucent FS), and that means FS changes to allow >>> translucence and to divorce volume mappings from the need for a mount >>> point (basically, a shadow / and /dev on which the devfs /dev is mounted >>> and the real / is mounted over top of the shadow /). >> >> I think that's not needed > > Root remount, again. If you divorce the mappings, you can mount root > over and over despite devfs being mounted by default. I'm not sure I understand all this, but never mind. What would be wrong with doing something like this.. At boot time the kernel creates a memory-filesystem (mfs or other) with a /dev directory. During the device probes this /dev gets populated with appropriate device entries. At the end of the kernel initialisations the kernel union mounts the root disk over the memory /. For those detractors in a previous thread this would also allow those who are so inclined to have their own custom modifications to /dev or even to remount their root without the union to keep using the old method. George.
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