On Fri, Dec 4, 2009 at 3:36 PM, Robert Millan <r...@aybabtu.com> wrote: > On Thu, Dec 03, 2009 at 06:27:07PM -0600, richardvo...@gmail.com wrote: >> 2009/12/3 Vladimir 'φ-coder/phcoder' Serbinenko <phco...@gmail.com>: >> > Chris Jones wrote: >> >> I am trying to have grub boot off a partition on a USB stick. >> >> >> >> >> > You can't chainload to disk invisible by BIOS. But you can load >> > supported OSes from it. >> >> What would be necessary to enable chainload to such devices? Install >> an IRQ 19 handler? > > Yeah, something like that. In essence, GRUB acting as a BIOS. Sounds awful, > but hey we already have "efiemu".
As Vladimir says, the legacy grub "map" command must already be installing such a hook (although it proxies implementation to the existing BIOS after changing the drive number, rather than calling a grub storage driver). > >> Invoke the extension ROM of the host adapter so >> that it hooks IRQ 19? > > There's usually no such ROM. Except for adapters that come in discrete > PCI cards. And even then, I doubt it's always present. There are actually quite a lot of devices like this. Most notebooks have broken BIOS that won't load the extension ROM from a PCMCIA slot, if grub could do so it would enable booting from a wide variety of PCMCIA/CardBus/ExpressCard-to-SCSI/SATA/USB adapters. Here's one example that I happen to own, and got frustrated with system BIOS not allowing boot from expansion card: http://www.newegg.com/Product/Product.aspx?Item=N82E16820161325&cm_re=SolidGO-_-20-161-325-_-Product I'm fairly sure there is an extension BIOS because some people report being able to boot from it, however most laptops cannot. > > -- > Robert Millan > > The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and > how) you may access your data; but nobody's threatening your freedom: we > still allow you to remove your data and not access it at all." > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > http://lists.gnu.org/mailman/listinfo/grub-devel > _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel