[Fedora-livecd-list] Working to support multiple images from a medium

[Jeremy Katz]

It keeps coming up that people would like to support multiple live
images running off the same USB stick/hard drive/$arbitrary medium and
so it's probably worth considering some of the ways that it could
possibly be supported.  Also, for the personal reason, it would make it
easier for me to effectively use my netbook with the super-slow SSD if I
just put a new rawhide live image on it regularly and keep my homedir on
the (faster) SD card :-)  

Breaking it down into components, I think there are a few things which
we have to worry about
0) Where to put things on the disk.  The more I think about it, the more
I think that having "everything" for one image (including the bootloader
bits) will be easiest.  The part we had talked about last about using
the iso label for namespacing seems to make reasonable sense

1) Boot loader config
There are a couple of possibilities here... the simplest would just be
that we edit the syslinux.cfg and append more entries.  A little bit
more complicated would be to just have a simple "top-level" syslinux.cfg
which uses CONFIG directives to load the additional config files.  Third
would be a com32 module to iterate and set up the menu items
automatically.  I lean towards the second, at least for at first.

2) How to know the new directory
There are multiple places scattered that have hard-coded looking for
LiveOS.  There's the initrd, there's the livesys initscript and there's
livecd-iso-to-disk/liveusb-creator.  While we could add a kernel command
line option[1] and go and change each of these to set it/respect it, it
feels like maybe the less general solution.  Maybe it's just that we
should always have livelabel= available so that we can use it other
places ?  I don't know.  Open to other thoughts and suggestions.

What do people think?  Is this worth doing?  Other ideas on
implementation?  Anyone want to start whipping up any patches?

Jeremy

[1] Till Maas sent a patch along these lines back in November and I've
kept meaning to get back to it.  So consider this doing so :)