Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
New method to create livecd
View unanswered posts
View posts from last 24 hours

 
Reply to topic    Gentoo Forums Forum Index Documentation, Tips & Tricks
View previous topic :: View next topic  
Author Message
nklb
n00b
n00b


Joined: 27 Jun 2002
Posts: 42

PostPosted: Fri May 27, 2005 6:28 am    Post subject: New method to create livecd Reply with quote

I have been tasked with creating a few livecd's for my school (Eastern Michigan University) and have used the thread here at https://forums.gentoo.org/viewtopic-t-244837-postdays-0-postorder-asc-highlight-qemu-start-0.html as a guide along with http://linuxfromscratch.org/~jhuntwork/livecd/ and my own discretion.

I have successfully created a working gentoo livecd that uses initramfs exclusively (NO initrd) and that mounts a read/write filesystem (unionfs) first thing, before the normal init stuff is called. There are still a few bugs to tweak out of it, but as a whole it works quite well. The best way to try it is to download the iso and see what was done firsthand, but unfortunately I have extremely limited upload so am not sure as to how to best share the .iso

I use ISOLINUX
When I used grub as mentioned in the first howto linked to above, I found it worked great on most machines but did not work on a select few, particularly laptops. Because I want compatability to be as high as possible, I have found it best to avoid grub and to use ISOLINUX instead.

Instead of using initrd as mentioned in the first howto, do what the second suggests and use initramfs. You can include the entire filesystem (except /dev, /proc, and /sys) because we will unionize it with a ram disk before the system is initialized!

The system setup (verifying cd, mounting initial filesystem, etc...) is done by a c script compiled into the initramfs image as seen in the 2nd howto.

This c-script even mounts the compressed squashfs image to /dev/loop0 (I am not aware of any other such init scripts that are capable of doing this at such an early point) and then init, first thing, creates the unionized filesystem and pivot_root()'s to it.

At this point I am still fairly early in development, but the system DOES bootup perfectly well. When I finish enough of the project I will write a much larger howto which I will post here, but for now I will just answer any questions anyone may have and do my best to provide the iso to anyone who is curious.
Back to top
View user's profile Send private message
irondog
l33t
l33t


Joined: 07 Jul 2003
Posts: 715
Location: Voor mijn TV. Achter mijn pc.

PostPosted: Sat May 28, 2005 12:54 pm    Post subject: Reply with quote

Very cool idea, I like it.

I think It will be a lot of work to provide the same range of hardware support into your C 'script' the knoppix and the Gentoo LiveCD's offer. If someone for example uses a scsi, usb or firewire CDROM you need to do some (mod)probing before being able to mount stuff. On the other hand, I think some performance improvements can be made this way. We loose the need of a sh binary and C programming in common is a lot faster than sh.

I really like it. Maybe I can offer some webspace for your project, contact me if you're interested.
_________________
Alle dingen moeten onzin zijn.
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Documentation, Tips & Tricks All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum