Making RO files Writable


Forum: DSL Embedded
Topic: Making RO files Writable
started by: desnotes

Posted by desnotes on May 20 2006,18:30
For experimental purposes only I would like to be able to boot the KNOPPIX/KNOPPIX into write mode in order to test some tweaks on some of the bash scripts. Is this possible? Something easier than remastering the whole distribution just to test out a few lines in a bash script. Installing to the HD won't work because I want to add tweaks when checkbootparam="qemu"

Any ideas?

Thanks,

desNotes

Posted by mikshaw on May 20 2006,19:45
KNOPPIX is a compressed iso file, and can't be mounted read-write (as far as I know).  The ISO9660 filesystem is read-only by design.

Depending on whether or not the tweaks must be done during the early stages of the init process, you could use a knoppix.sh script to change the behavior of DSL at runtime.  The knoppix.sh script, if it exists in KNOPPIX or a specified location, runs at the end of knoppix-autoconfig (before the DSL-specific stuff is done).

Posted by desnotes on May 20 2006,20:09
What I am hoping to do is to try tweaking the  knoppix-autoconfig script when used in Qemu. Qemu emulates certain hardware so what I want to do is have the autoconfig script detect what qemu is emulating rather than searching to find the right match.

Going through the excercise will help me get familiar with bash, the boot up process and if I am lucky, shave off a few seconds of the boot process.

If I can make the KNOPPIX file write enabled I will need to set up a process where I can make the change, compress the diectory and then copy it over. Not nearly as fast but...

thanks,

desNotes

Posted by pr0f3550r on May 21 2006,10:30
Desnotes,

I am using the iso rather than the KNOPPIX embedded, but I think the concept is similar.

In my case KNOPPIX is read only but root is rw:

Code Sample
dsl@box:~$ mount
/dev/root on / type ext2 (rw)
/dev/scd0 on /cdrom type iso9660 (rw)
/dev/cloop on /KNOPPIX type iso9660 (ro)
/ramdisk on /ramdisk type tmpfs (rw,size=98868k,size=94665k)


Most of what is in KNOPPIX is in / :
Code Sample
dsl@box:~$ diff /KNOPPIX/ /  
Only in /KNOPPIX/: .rr_moved
Only in /: KNOPPIX
Common subdirectories: /KNOPPIX/cdrom and /cdrom
Common subdirectories: /KNOPPIX/dev and /dev
Common subdirectories: /KNOPPIX/etc and /etc
Only in /KNOPPIX/: floppy
Common subdirectories: /KNOPPIX/home and /home
Common subdirectories: /KNOPPIX/mnt and /mnt
Only in /KNOPPIX/: none
Common subdirectories: /KNOPPIX/opt and /opt
Common subdirectories: /KNOPPIX/proc and /proc
Only in /: ramdisk
Common subdirectories: /KNOPPIX/root and /root
Only in /: sys
Common subdirectories: /KNOPPIX/var and /var


IMHO you could work on the root filesystem as a temporay sandbox, if this is what you want.

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