LinuxBIOS Bootup
Eric W Biederman
ebiederman at lnxi.com
Thu Aug 29 02:12:01 CEST 2002
Balbir Singh writes:
>
> Hello, List,
>
> I need the following clarification about the LinuxBios boot up
> information
>
> 1. Can LinuxBios boot from CDROM?
> 2. Can LinuxBios boot from a SCSI Disk?
Yes. But the drivers have not yet been written.
> 3. Does anybody have a FAQ or collected information about how the
> LinuxBios
> bootup sequence works?
Not especially as this is a work in progress, at the moment.
The design:
- All booting under LinuxBIOS will load standalone executables
that do not need BIOS calls to access the hardware
- Information will be passed in the LinuxBIOS table to the loaded
kernel.
- The LinuxBIOS core will have a dumb bootloader with one hardware driver
and it will load static ELF executables, this is to prevent feature
bloat.
- Either the LinuxBIOS core loads the final kernel, or it loads a bootloader.
- Either the bootloader is stupid and scans ~= the first 8K of a device looking
for an ELF image to boot, or it is smart and parses filesystems.
On the side of stupid bootloaders, I have just finished enhancing the
development version of etherboot:
http://www.etherboot.org
So that it has allows the specification of a boot order, (compile
time, run time or a cmos option). This supports quite a few NICs,
and IDE, and floppies. Though the code needs a little more
stabalization work.
The bootloader story with LinuxBIOS is a work in progress, but some
good options are starting to emerge.
Adam Agnew, and Ollie Lho have a forked version of etheroboot with
filesystem support. The infrastructure is in place so it can probably
be merged cleanly.
There is work on using the kernel as a bootloader with a linux booting
linux patch.
I have targeted etherboot first because it can be quite small,
allowing for more options in rom chips. With every driver compiled in
etherboot is ~= 65KB, and with the eepro100 and the ide driver it is
~= 15KB.
Eric
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