Persistent configuration on the VMU

The most important file is /etc/init.d/rc.S found on the VMU. So, we first have to prepare the VMU for storing the persistent configuration. Boot your SEGA Dreamcast and plug in the VMU. You'll notice some Linux kernel messages about the found flash memory system. Log in as root and type in:

# mkfs.minix /dev/mtdblock0

Now, your VMU is formatted. Following, you can mount your VMU for storing files:

# mount -t minix /dev/mtdblock0 /mnt

Your flash memory is now accessible under /mnt. The first file being created is /mnt/etc/init.d/rcS:

# mkdir -p /mnt/etc/init.d
# cat <<. >/mnt/etc/init.d/rcS
#!/bin/sh

PATH=/bin:/sbin:/usr/bin:/usr/sbin

echo "Setting up filesystem..."

# First, set up the users.
rm -f /etc/passwd
rm -f /etc/shadow
rm -f /etc/group
rm -f /etc/gshadow
ln -s /mnt/etc/passwd /etc/passwd
ln -s /mnt/etc/shadow /etc/shadow
ln -s /mnt/etc/group /etc/group
ln -s /mnt/etc/gshadow /etc/gshadow

# Then, set up hosts.
rm -f /etc/hosts
ln -s /mnt/etc/hosts /etc/hosts

# Now, set up ADSL connection.
cp /mnt/etc/ppp/pap-secrets /etc/ppp
cp /mnt/etc/ppp/pppoe.conf /etc/ppp

# Following, prepare SSH host_key.
cp /mnt/etc/ssh/ssh_host_key /etc/ssh
cp /mnt/etc/ssh/ssh_host_key.pub /etc/ssh

# Then, we set up the /home directories.
ln -s /mnt/home/christian /home/christian

echo "Setting hostname..."
hostname hercules

# If you have a german keymap
#echo "Setting keymap..."
#loadkmap < /mnt/usr/share/keymaps/qwertz.map

echo "Configuring lo..."
ifconfig lo 127.0.0.1 up

echo "Configuring eth0..."
ifconfig eth0 192.168.1.1 up

echo "Starting klogd..."
klogd

echo "Starting syslogd..."
syslogd

echo "Starting udhcpd..."
udhcpd

echo "Starting yaku-ns..."
/usr/yaku-ns/yaku-ns -c /usr/yaku-ns/yaku-ns.conf \
 -l /usr/yaku-ns/yaku-ns.log -u yaku -d

echo "Starting sshd..."
sshd -f /etc/ssh/sshd_config

sleep 1

echo "Everything's done. Have fun."
.
# chmod 744 /mnt/etc/init.d/rcS

The first few lines remove the generic passwd - and group - files and replace them with my personal configuration.

The next two lines set up a specific /etc/hosts - file.

Following, my personal ADSL account information will be copied to the root filesystem.

Furthermore, the SSH specific host_key pair files (please see chapter eight) are transferred to the root file system.

Last but not least, my personal home directory with a SSH public key is linked to the root file system.

Obviously, you have to create or copy every linked or copied file from this script to your VMU. I suggest following procedure:

1. Create a special directory on your host.

2. Create or copy every needed file desired to be persistent to this directory.

3. Change both the /etc/init.d/rcS on your SEGA Dreamcast and the corresponding /etc/init.d/rcS for your VMU copying or linking every needed file.

4. Change carefully the mode and owner of each file.

5. Archive the complete directory into one single file:

   $ cd persistent_configuraton
   $ tar -cvpf ../vmufs.tar .
   

   The option -p is necessary for preserving the modes of the single files.

6. Transfer the file vmufs.tar to your SEGA Dreamcast using wget for example (assuming you're running a local web - or ftp - server):

   # cd /tmp
   # wget http://192.168.1.11/vmufs.tar
   

7. Unpack the archive on the mounted VMU:

   # mount -t minix /dev/mtdblock0 /mnt
   # cd /mnt
   # tar -xvf /tmp/vmufs.tar .
   

8. Unmount the VMU and reboot you SEGA Dreamcast for testing your persistent configuration.

This procedure has two advantages: First, you don't need to edit and change your persistent configuration directly on your SEGA Dreamcast, and second, you've got a backup of your configuration on your host.