Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/17/84 chuqui version 1.7 9/23/84; site nsc.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!nsc!chongo From: chongo@nsc.UUCP (Landon C. Noll) Newsgroups: net.unix-wizards Subject: 4.2 Info request: Read-only file systems Message-ID: <2483@nsc.UUCP> Date: Mon, 18-Mar-85 15:58:16 EST Article-I.D.: nsc.2483 Posted: Mon Mar 18 15:58:16 1985 Date-Received: Tue, 19-Mar-85 07:58:58 EST Distribution: net Organization: Rational Swamiconductor, Sanivale Lines: 22 I would like to mount things like /bin, most of /etc, /usr/{bin,lib, ... }, /dev/{mem,kmem,...}, usw... on a read-only disc pack. What is needed (if it can be done) to be done to unix to allow this? A guess is that one needs to change the mountfs call in init_main.c to pass a read-only flag. One would need to add an additional mountfs call to mount a second writable pack. Files which need to be written such as /etc/utmp, or /usr/adm would be symbolicly linked over to the write pack. What problems are connected with that? What about the /dev/ttyxx files. To allow getty/login to play with the ownership, one might need to symbolic link to the write pack as well. Will this cause a problem? Does unix assume that it can write on root? (my guess again is that one the superblock timestamp update for root is not needed since I can get the starttime for a real time clock) What about last file access times? chongo /\../\ -- no comment is a comment.