Okuji: Why the modaddr can not be accepted by multiboot specification ? By default, grub loads the multiboot modules right after multiboot kernel. Some microkernel want to keep the multiboot module images in memory, if a driver crashed it can be reloaded from the image. On x86 platform, this scheme will consume much DMA memory. So a command like modaddr is very useful to save memory in DMA area. I dont know whether other platforms use Grub, but x86 is the most popular one.
Best regards. Coly 在 2007-03-24六的 23:57 +0100，Yoshinori K. Okuji写道： > On Friday 23 March 2007 16:46, Wei Shen wrote: > > 1) Simple file editing > > > > I think it is useful to add file edit function to Grub. Thus, if a config > > file which is required to boot the OS successfully is mistakenly written, > > we can still correct it in Grub and need not to reboot from the floppy or > > cdrom just for the correcting. > > I know it would greately increase the complexity of Grub to support a > > writable file system. However, if file writing does not change the block > > number of a file, things are much simpler. Since most config files are > > small (occupying only one block), I think the solution will work. > > If you don't change the file size, it would work mostly. And this is exactly > how "savedefault" works in GRUB Legacy. > > But I am a bit pessimistic with this approach. For example, ZFS computes a > checksum for every block, and embeds the information into a parent node. This > means that, when GRUB modifies any bit of data, GRUB must recompute a > checksum and write it to somewhere appropriate. Otherwise, a filesystem would > be corrupted. > > Theoretically speaking, nothing prevents GRUB from doing that. But this > illustrates that GRUB must deal with writing very carefully, and the > semantics depends on each filesystem. I do not know if a kind of volume > manager, such as LVM, performs this kind of check, but if it does, we need to > support it as well. > > So this work is not as trivial as at the first glance, although we need it > for > "savedefault" definitely. > > > 2) *addr* option for module command > > > > Add nn option: "*addr* = *value*" to the module command. If the > > *addr*option is specified, Grub will load the module to address > > *value* instead of the default address. > > We discussed this in bug-grub a long time ago. If you are interested, please > look at the archive, and search by "modaddr". > > In summary, I do not like this, because it is a non-standard extension to > Multiboot Specification. If you depend on this feature, your users would be > restricted to using GRUB, and they would not be able to use any other > Multiboot-compliant boot loaders. This is against the spirit of the Multiboot > Specification, which addresses portability problems in boot protocols. > > So this must be accomplished as a part of Multiboot Specification. Otherwise, > I do not want to accept it. > > Thanks, > Okuji > > > _______________________________________________ > Grub-devel mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/grub-devel _______________________________________________ Grub-devel mailing list [email protected] http://lists.gnu.org/mailman/listinfo/grub-devel
