[syslinux] Append boot device to /proc/cmdline
Shao Miller
Shao.Miller at yrdsb.edu.on.ca
Wed Dec 2 15:39:50 PST 2009
H. Peter Anvin wrote:
>
> Actually, a lot of people object to it, and so it will not be done
> unconditionally.
>
For example, there're more than just the Linux kernel that conform to H.
Peter's i386 Linux boot protocol [1]. Other such items might not
appreciate the extra information you've suggested that Syslinux provide
automatically, Patrick.
> Well, it really isn't a trivial question to answer even with help from
> the bootloader, as the BIOS view of things and the Linux view of things
> can be dramatically different.
>
For example, the checks you suggested, Patrick, regarding HDD size or
filesystem type seem rather arbitrary. For Syslinux to implement this
unconditionally would mean that it would be expected to support this
forever more. Even passing a BIOS drive number such as 0x00, 0x80,
0x81, 0xA0, 0xE0 does not help since it is not a guaranteed one-to-one
mapping to Linux devices. There might even come a time when such
information is not relevant because there is some other, more efficient
means of notifying the OS of the correct boot media. An example would
be the iSCSI iBFT. Who knows? Perhaps ACPI tables will be the future
preferred method for this kind of thing. To suggest appending the
filesystem type or the HDD size to /proc/cmdline, I wonder if you
attempt to rally all Linux distributions towards that cause and check
the response, what it will be like.
That's not at all to say that a particular COM32 module or some special
option could not benefit your particular needs, Patrick. Parted Magic
is nice.
[1] linux/Documentation/i386/boot.txt
- Shao Miller
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