Date: Sun, 30 Mar 2003 15:55:38 -0500 (EST) From: "J. Seth Henry" <jshamlet@comcast.net> To: questions@freebsd.org Subject: /dev on a read-only filesystem? Message-ID: <20030330154319.I73024-100000@whitetower.gambrl01.md.comcast.net>
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I have managed, through hook and crook, to get a full 4.7-REL install on a Compaq IA-1 internet appliance. I put a kernel, /bin, /etc, /boot, /dev, /proc, and a partial /sbin on the internal flash memory. During boot, I mount a complete /sbin, /usr and <swap> on a microdrive. Since I want to reduce the number of writes to the flash, I linked /tmp, /var, and /root to directories in /usr. So far, so good - the bulk of the write/update activity is now pointed to the microdrive which has no physical write limits. The trick is, if I make / read-only, I run into problems with /dev. During boot, I get numerous error messages - and things don't seem to work quite right. Is there a way to mount / read-only, while maintaining a working /dev? Can /dev be mounted from another filesystem - or, preferably (since the OS is already running) be linked to, say, /usr/dev? If not, how much write activity to the actual, physical volume takes place in /dev. Also, does anything happen on the physical disk with /proc. I don't think it does squat to the physical disk, since a "procfs" filesystem is mounted there, but I want to make sure I don't damage the flash with periodic writes. I would feel best if the internal flash were completely read-only. BTW - if it wasn't clear, the system boots from flash, and them mounts the microdrive. Also, and perhaps unrelated, if I attempt to run getty from the flash, I get an error message about getty spawning too fast - and I can't ever login on the console. This doesn't happen when I launch getty from the microdrive. Odd, but unimportant - as the microdrive is necessary for the system to "run" Thanks, Seth Henry
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