4.4. Implementation
We will need to have a read-write filesystem in order for some of
the commands to work. The kernel's normal behavior is to mount root as
read-only, but we can change this using a kernel option. By passing the
kernel the rw option before
init=/bin/sh we will get a read-write root
filesystem.
4.4.1. System startup
Follow these steps to get the system running.
Boot the PC from using the GRUB boot disk.
At the grub> prompt, type
kernel (fd0)/boot/vmlinuz rw init=/bin/sh root=/dev/fd0
load_ramdisk=1 prompt_ramdisk=1.
Verify that you remembered to add the
rw parameter and press
Enter.
Type boot and press Enter.
Insert the recently created root disk when prompted.
The terminal display should look similar to the example
below.
GNU GRUB version 0.95
grub> kernel (fd0)/boot/vmlinuz rw init=/bin/sh root=/dev/fd0 load_ramdisk=1 prompt_ramdisk=1
[Linux-bzImage, setup=0xc00, size=0xce29b]
grub> boot
Linux version 2.4.26
..
.. [various kernel messages]
..
VFS: Insert root floppy disk to be loaded into RAM disk and press ENTER
RAMDISK: Compressed image found at block 0
VFS: Mounted root (ext2 filesystem) read-write.
Freeing unused kernel memory: 178k freed
# _ |
4.4.2. Testing new commands
Now that the system is up and running, try using some of the new
commands.
bash# uname -a
bash# ls /etc
bash# echo "PocketLinux" > /etc/hostname
bash# hostname $(cat /etc/hostname)
bash# uname -n
bash# mkdir /home/stuff
bash# cd /home/stuff |
If everything goes well the commands like cat,
ls and hostname should work now.
Even mkdir should work since the root filesystem is
mounted read-write. Of course since we are using a ramdisk, any changes
will be lost once the PC is reset.
4.4.3. System shutdown
Remove the diskette from fd0 and restart the system using
CTRL-ALT-DELETE.
