Loop device

[Vignesh]

Thanks again... I installed Breezy Server so saved time in
installation.. I installed it before your message
Mounted the iso successfully... the original Hoary iso not my custom
made


On Thu, 2006-06-08 at 16:21 +0200, email.listen at googlemail.com wrote:
> Am Thu, 8. June 2006 12:44 schrieb Vignesh:
> > First things first , Thanks Thomas for the time you spent on this...
> I will never forget the trouble I had when I used loop devices for creating a 
> cloop image. As I like to say, 'Often I was close to bite the edge of the 
> table' (german: Oft war ich kurz davor in die Tischkante zu beissen)
> Not to forget I only had Internet in the university and my computer was at 
> home...
> 
> > I renamed the iso image to ubuntu.iso
> >
> > root at ubuntu:/home/vignesh # mount -o loop -t iso9660 ubuntu.iso mnt
> > mount: could not find any device /dev/loop#
> >
> > Before Reboot
> > root at ubuntu:~ # ls -lR /dev/loop*
> > ls: /dev/loop*: No such file or directory
> >
> > After Reboot
> >
> > root at ubuntu:~ # ls -lR /dev/loop*
> > ls: /dev/loop*: No such file or directory
> Uuups :-/
> I would expect an /etc/loop/ directory containing entries 0 to 7 or 
> devices /dev/loop0 to /dev/loop7.
> What makes me think may be you deleted them?
> If you build your own customised live-cd ther must have been at least one loop 
> device. No loop device, no cloop to build an own live-cd. Cloop uses a loop 
> device too.
> 
> Never mind, there is always a way to solve a problem in GNU/Linux universe...
> 
> If you do a:
> ls /dev/MA*
> 
> You will find a '/dev/MAKEDEV' which is a link to /sbin/MAKEDEV.
> Precisely MAKEDEV is a shell script to create device entries in /dev/.
> A 'man MAKEDEV' gives a lot of information about its services, a bit confusing 
> for beginners. In short, chapter standard devices says that it will create 
> loop devices from 0 to 7 if it is started as 'MAKDEV loop'.
> You have to be in the /dev directory first before starting MAKEDEV!
> 
> So open a terminal, become root by typing:
> sudo -s
> Enter your user password, go to the /dev directory (use cd).
> And then start:
> MAKEDEV loop
> 
> You shoult see the new loop0 to loop 7 devices when you type:
> ls -lR /dev/loop*
> 
> see also [1]
> 
> Now follow my last posting for mounting the iso image.
> (we are getting closer to solve your problem :-))
> 
> 
> [1] Background information
> 
> This (using MAKEDEV) was for a hoary system 
> For a Dapper system the loop devices will disappear in the next reboot. 
> This because dapper uses udev which creates devices in a much more dynamic way 
> than it is done in hoary which uses devfs.
> 
> For dapper there are two ways to have all loop devices at bootup.
> 1) As recommended in /usr/share/doc/udev/README.gz:
>   - It is recommended to use the /lib/udev/devices directory to place
>     device nodes and symlinks in, which are copied to /dev at every boot.
>     That way, nodes for broken subsystems or devices which can't be
>     detected automatically by the kernel, will always be available.
> 
> So open a terminal and become root.
> Go to the /lib/udev/devices/loop/ directory.
> (A 'ls -l' shold show a device 0)
> 
> Create the new loop devices from 1 to 7 by typing:
> mknod 1 b 7 1
> mknod 2 b 7 2
> mknod 3 b 7 3
> mknod 4 b 7 4
> mknod 5 b 7 5
> mknod 6 b 7 6
> mknod 7 b 7 7
> 
> Restart udev by typing:
> /etc/init.d/udev restart
> 
> You now should see the new devices by typing:
> ls -lR /dev/loop*
> 
> 
> 2) An entry in /etc/udev/links.conf
> 
> Start gedit as root, press <Alt>+<F2> and type:
> sudo gedit /etc/udev/links.conf
> 
> Paste the following:
> 
> # hack to have loop devices from loop/0 to loop/7
> M loop/1 b 7 1
> M loop/1 b 7 1
> M loop/2 b 7 2
> M loop/3 b 7 3
> M loop/4 b 7 4
> M loop/5 b 7 5
> M loop/6 b 7 6
> M loop/7 b 7 7
> 
> Save the file.
> 
> Restart udev from a terminal by typing (as root):
> /etc/init.d/udev restart
> 
> You now should see the new devices by typing:
> ls -lR /dev/loop*
> 
> > root at ubuntu:~ # mount
> > /dev/hda5 on / type ext3 (rw,errors=remount-ro)
> > proc on /proc type proc (rw)
> > sysfs on /sys type sysfs (rw)
> > devpts on /dev/pts type devpts (rw,gid=5,mode=620)
> > tmpfs on /dev/shm type tmpfs (rw)
> > /dev/hda2 on /mnt/shared type ext3 (rw,noexec,nosuid,nodev)
> > usbfs on /proc/bus/usb type usbfs (rw)
> Ok, no loop mounted.
> 
> >
> >  The image is my custom made Hoary livecd`s iso so I don`t remember the
> > exact md5sum but I got this...
> If it is your own iso image it may be a good idea for the next image you 
> create also create an md5 file.
> For this open a terminal and go to the directore where the image is stored.
> 
> To create a md5 file type:
> md5sums Nameofyourimage.iso > Nameofyourimage.iso.md5
> 
> So you may check your own images md5 sum the next time.
> A 'md5sums Nameofyourimage.iso' shold always be the same what is saved 
> in 'Nameofyourimage.iso.md5'
> 
> 
> > root at ubuntu:/home/vignesh # md5sum ubuntu.iso
> > 58d90d71192b0436343871919d8cd310  ubuntu.iso
> >
> > root at ubuntu:/home/vignesh # file ubuntu.iso
> > ubuntu.iso: data
> >
> > This is what I get.. So I can`t use this to make my next version of the
> > livecd or what. I have a burned version of the bootable livecd , can I
> > use that to make a bootable iso ?
> A bootable iso?
> You are talking of an iso image which is used on bootup to start the system?
> As far as I know, no.
> 
> But you can use a live cd to customize it to your needs.
> For this you may find informations on the site of Klaus Knopper, the man who 
> brought Knoppix to us. (Applause, Laola, Soundtrac of a bombastic movie, 
> somewhat like Franfred Man's Earth Band, Fanfare for a Common Man)
> 
> 
> > OK... I copied the Hoary live iso.. I will use that itself..
> Hmmm. it might be a better idea to use one of the dapper live CD's.
> Or better than that, use a Knoppix. This because knoppix uses the unionfs file 
> system, one of the most best advantages in my opinion.
> 
> 
> > root at ubuntu:~ # mount -o loop -t iso9660 ubuntu-5.04-live-i386.iso mnt
> > mount: could not find any device /dev/loop#
> Ok, that is what we should expect. No loop device no loop mount.
> And this sounds much better than the messages you showed in your former 
> postings. 
> 
> > root at ubuntu:~ # file ubuntu-5.04-live-i386.iso
> > ubuntu-5.04-live-i386.iso: ISO 9660 CD-ROM filesystem data 'Ubuntu 5.04
> > i386            ' (bootable) root at ubuntu:~ #
> >
> OK, this is the original hoary live-cd, isn't it?
> 
> 
> I would say after creating new loop devices you should be able to mount your 
> image.
> 
> regards,
> thomas
> 
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