Mailing List Archive

rob beard (JIC) wrote:
> Hi,
>
> I was wondering if it is possible to have the option to boot from hard disk
> when syslinux loads from floppy.
>
> Basicly I'm trying to create a boot disk which gives me the option to boot
> from hard disk, possibly after 5 seconds incase I leave the floppy in by
> mistake.
>
> The systems I would be using this floppy on would be running Windows NT 4.0,
> Windows 2000 and possibly RedHat Linux 7.2.
>
> Is this possible?
>

Not in the current version. Well, it *sort of* is... you could write a
COMBOOT program to chainload a harddisk. Hmmm... you got me thinking
now. Always a dangerous thing.

No new projects before 1.70 is out, though. Anyone who can try out
1.70-pre1 and give me feedback would help that process along...

-hpa

On Fri, 05 Apr 2002 12:15:50 -0800, "H. Peter Anvin" <hpa@zytor.com> wrote:

>> I was wondering if it is possible to have the option to boot from hard disk
>> when syslinux loads from floppy.

>Not in the current version. Well, it *sort of* is... you could write a
>COMBOOT program to chainload a harddisk. Hmmm... you got me thinking
>now. Always a dangerous thing.
>

I'm not sure if this is the same thing you're talking about, but if the hard
disk already have a boot loader on it (ie: lilo), can't you chainload the
512 boot sector directly?

dd if=/dev/hda of=bootsect.bs bs=512 count=1

kernel bootsect.bs

I used this to build remote systems (I could not put floppy in and out)
starting them from floppy and then rebooting them from HD (with the syslinux
floppy still inside), then from HD I could edit syslinux.cfg and have it
rebooted from floppy, and so on.

--
giulioo@pobox.com

Giulio Orsero wrote:
>
> I'm not sure if this is the same thing you're talking about, but if the hard
> disk already have a boot loader on it (ie: lilo), can't you chainload the
> 512 boot sector directly?
>
> dd if=/dev/hda of=bootsect.bs bs=512 count=1
>
> kernel bootsect.bs
>
> I used this to build remote systems (I could not put floppy in and out)
> starting them from floppy and then rebooting them from HD (with the syslinux
> floppy still inside), then from HD I could edit syslinux.cfg and have it
> rebooted from floppy, and so on.
>

This *can* work, but it isn't guaranteed to work because the DL register
will contain the wrong drive number. It works for LILO, I'm pretty
sure, but may not work for other systems.

-hpa