On Sat, Apr 02, 2011 at 12:50:29AM -0700, [email protected] wrote: > Mehmet Erol Sanliturk <[email protected]> wrote: > > > For a long time I am thinking to obtain a physically ( not only > > software ) based [read-only] FreeBSD edition by re-arranging some > > parts of it , but I do not know how to do it ... > > > After some years , MFM hard disks abandoned in favor of IDE > > ( Integrated Drive Electronics ) hard disks by moving controller > > to hard disk and eliminating use of add-on cards with a very > > unfortunate design decision as ( a write protect mechanism by > > a switch on the hard disks are not implemented ) . > > At least some IDE drives have write-protect jumpers, which could > presumably be replaced with connections to switches. > > > With respect to my knowledge , no one of the operating systems > > has a facility to separate read-only and modifiable parts ... > > SunOS 4 had a partial solution to this, by rearranging the FS layout > so that /usr could be mounted read-only (and often, from a server -- > IIRC a single /usr could be shared among multiple diskless clients). > They used quite a few symlinks so that things could be found in > their accustomed places although actually located elsewhere. The > scheme was fairly well described in the SunOS 4 manual set; granted > _finding_ a SunOS 4 manual set these days may be a challenge :)
In fact, FreeBSD is very similar, /etc and /usr/local/etc may be written to for configuration purposes after building your system, /tmp and /var should really be writable (temp files, log files, sockets etc.) /home other application directories of course depend on the particular application and the rest can be r/o. Embedded systems (please read the freebsd-embedded mailing list) deal with similar issues and that's what nanobsd(8) was written for. Read http://www.psconsult.nl/talks/AsiaBSDcon2010-Servers if you want to see that similar techniques can also be applied to servers. Regards, Paul Schenkeveld _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[email protected]"
