Re: Live softphone USB key.: Progress report
palama@inwind.it wrote:
- Two of these machines have a BIOS which is not capable of booting
off a USB key. It is certanly possible
to boot on these machines using a boot floppy
It's important to understand that for a computer beeing able to use USB
disk, it needs some drivers. Where do they come from ?
a) From modern BIOSes: they support booting of USB disk by supplying a
poor-man driver which is only available to the boot-loader and only for
the disk used to boot from. This allow boot-loaders to load kernel and
initramfs from the USB disk they where booted from, not from another one
! But once control is given to kernel, this driver is no longer available.
b) From linux kernel modules in initramfs.
With a PC BIOS not supporting USB boot, it is worth knowing that most
popular boot-loaders do not have USB driver, even Grub2. It means that
having boot-loader on floppy ( it fits !) and kernel/initramfs on
liveUSB doesn't work with Lilo/Syslinux/Grub{1,2}.
For this config to work you have to use a boot-loader *with* USB
drivers, and of course this boot-loader exists and is well known, it's
Linux kernel !: http://www.solemnwarning.net/kexec-loader/ will do the
trick: it fits on a floppy ! When BIOS starts it, it loads a temporary
linux kernel and initrd with USB drivers and in a second stage, the
liveUSB kernel and initramfs is loaded and passes control to.
I have this config working with my liveUbuntu 9.10 built with
live-helper, quite easy to do.
Ph.L.
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