Here is some notes to build your own fs :
the fs must have the basic structure
and config files : inittab, fstab, rc
devices : tty...
mke2fs -m 0 -N 1889
mount -t ext2 /tmp/loop /mnt
/dev/ must have : kmem , mem , null , tam0 , tty1, console
df -l display inodes usage
ls -ltru list in reverse order of date last been accessed
rc.d should contain:
#!/bin/sh
/bin/mount -av
and fstab:

/dev/hdb3 / ext2 default
/dev/hdb2 /boot ext2 default
/proc /proc proc default


these files in /bin: getty, init, mount, sh



/lib:
ldd bin
include lbc, libc.so, ld.so, ld-linux.so
file lib



mkdir -p /mnt/var/(log,run)
touch /mnt/var/run/utmp
ldconfig -r /

In the Linux-Newbie forum the post will be lost. I don't have a good place to move it, however. If you have time you can write a Linux Tutorial about building a filesystem from scratch based on this post.