On Thu, Aug 21, 2003 at 02:15:24PM +0200, Niels M?ller wrote: > Philip Charles <[EMAIL PROTECTED]> writes: > > > For a GNU live CD to work a hurdish ramdisk would have to be created and > > setup at the initial boot. > > I think that's what the gzip store type is for; it's a store that is > initialized by unpacking gzipped data in an underlying store. It > should be possible to use it with the plain ext2 translator, although > it might be inefficient compared to a specialized ramdisk fs. Hmm, we > probably don't even need the gzip store, as GRUB can inflate the image > for us. > > I'm a little confused about the Hurd boot procedure in general, but I > guess it should work like this: > > GRUB loads the kernel, the ext2 root translator, any other servers > (proc? ld.so?) which are needed for boot,
only ld.so, which then starts exec, which it can read from ext2fs. From there, ext2fs starts init, which then starts the rest (auth, proc). > and the gzipped ext2-image > (which must contain enough free blocks so that new files can be > written to it). > > The kernel wraps the loaded filesystem image into a memory object. Which is currently not supported :) > Then the ext2 server must be started with arguments that tells it to > use a supplied memory image as the underlying store. Theoretically possible. > When the root filesystem is running, control is passed on to some boot > script (/etc/runsystem?), which can install whatever additional > symlinks and translators that aren't present already in the filesystem > image, and start the rest of the system. > > I'm not sure what the missing pieces (if any?) are. The memory object > store type? That exists, I think. Probably untested. > The passing of the memory object between kernel and the > root ext2 server? The creation of a memory object from a grub module? Right, those are missing. Probably not too hard. > Another issue is that as we have no writable disks, the system must be > reasonably stable without swap, or one has to fake some swap by by > somwhow putting a swap file inside the ramdisk (ugly and wastes some > more memory). Yeah. Well, I think that the above procedure is mostly useful for diskless booting. For the CD Rom, a unionfs seems to be the better approach to me, as it saves a lot of RAM. Thanks, Marcus -- `Rhubarb is no Egyptian god.' GNU http://www.gnu.org [EMAIL PROTECTED] Marcus Brinkmann The Hurd http://www.gnu.org/software/hurd/ [EMAIL PROTECTED] http://www.marcus-brinkmann.de/
