About: <000901c14bb2$1183d980$de12fe81@etri.re.kr>
bgjung@etri.re.kr wrote:

>> >> /tmp, /var, /etc and /root is build on memory
>> >>file system. See below;
>> 
>> >>http://www.seki.ee.kagu.sut.ac.jp/~sakai/index.html
>> 
>> >>But, this page is written in Japanese.
>> 
>> Could you expalin how to build memory file system with /tmp, /var, /root in English brielfy?

See, 
/etc/rc.diskless{1,2} on FreeBSD-4.X.
http://www.seki.ee.kagu.sut.ac.jp/~sakai/cdbsd/download/rc.cdrom
http://www.seki.ee.kagu.sut.ac.jp/~sakai/cdbsd/download/mkrwfs.sh

These scripts are for CD-bootable FreeBSD. But, I succeeded to make CD-ROM
bootable NetBSD same as CD-bootable FreeBSD. These scripts can be used on
CD-bootable NetBSD too.

rc.diskless{1,2} are scripts to make writable directries (/etc, /var, ...)
on MFS for network-boot.

rc.cdrom is a script to mount /tmp, /etc, /root and /home at start.
And rc.cdrom copy /etc/*, /root/* and /home/* on CD-ROM to MFS's /etc,
/root and /home. And if FD is inserted at start, rc.cdrom copies etc/* on
FD to /etc.

I used rc.cdrom and rc.diskless2 to make writable directries at start for
CD-bootable FreeBSD and CD-bootable NetBSD.

mkrwfs.sh is a script to remount CD-ROM's read-only directry by MFS.
This script is used to change read-only directry to writable one when
you want to change a daemon's configuration file and restart the daemon.
Ex. /usr/local/etc/apache.

--
SAKAI Hiroaki
sakai.hiroaki@pfu.fujitsu.com
hsakai@m8.people.or.jp