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Just like creating the tiny version of FreeBSD, it is easy to create the mini-linux. First, download the latest linux kernel source package. Unpack it, and compile the new kernel. Second, download the latest busybox source package, unpack and compile it.

  rm -f /tmp/ramdisk.imgrm /tmp/ramdisk.img.gz
  # Ramdisk size
  # Create an empty ramdisk image
  dd if=/dev/zero of=/tmp/ramdisk.img bs=$BLKSIZE count=$RDSIZE
  # Make it an ext2 mountable file system
  /sbin/mke2fs -F -m 0 -b $BLKSIZE /tmp/ramdisk.img $RDSIZE
  # Mount it
  mkdir -p /mnt/initrd
  mount /tmp/ramdisk.img /mnt/initrd -t ext2 -o loop=/dev/loop0
  # Create directory tree
  mkdir /mnt/initrd/bin
  mkdir /mnt/initrd/sys
  mkdir /mnt/initrd/dev
  mkdir /mnt/initrd/proc
  mkdir /mnt/initrd/etc
  mkdir /mnt/initrd/var
  mkdir /mnt/initrd/tmp
  mkdir /mnt/initrd/www
  # copy busybox and create the symbolic links
  cp $1 /mnt/initrd/bin/.
  cd /mnt/initrd/bin
  prg=`./busybox | grep -e "z" -e "," |grep -v -e 'Copy' | sed 's/,/ /g'`
  for i in $prg; do
      ln -s busybox $i
  cd -
  # create the necessary dev files
  cp -a /dev/console /mnt/initrd/dev
  cp -a /dev/ramdisk /mnt/initrd/dev
  cp -a /dev/ram0 /mnt/initrd/dev
  cp -a /dev/null /mnt/initrd/dev
  # create link bin -> sbin
  cd /mnt/initrd
  ln -s bin sbin
  cd -
  # extract the packages, etc, bin, lib and www
  tar cpf - ./etc | (cd /mnt/initrd; tar xpf -)
  tar cpf - ./bin | (cd /mnt/initrd; tar xpf -)
  tar cpf - ./lib | (cd /mnt/initrd; tar xpf -)
  tar cpf - ./www | (cd /mnt/initrd; tar xpf -)
  # Create the linuxrc file
  cat >> /mnt/initrd/linuxrc << EOF
  mount -t proc /proc /proc
  mount sysfs -t sysfs /sys
  mount -t tmpfs -o size=1m none /tmp
  mount --remount,rw /
  mdev -s
  hostname NetClient
  httpd -h /www
  exec /bin/init
  chmod +x /mnt/initrd/linuxrc
  # Create the fstab file
  cat >> /mnt/initrd/etc/fstab << EOF
  /dev/ram0 /          ext2    defaults        1 1
  sysfs     /sys       sysfs   defaults        0 0
  # Done.
  umount /mnt/initrd
  gzip -9 /tmp/ramdisk.img
  cp -f /tmp/ramdisk.img.gz .

After creating ramdisk, move the kernel and ramdisk to tftpboot. Now the client can load the new kernel/ramdisk.

wiki/create_the_mini-linux.txt · Last modified: 2007/11/08 03:54 by mirnshi