[vox-tech] booting off cd help

[Ken Bloom]

On 2003.05.04 10:22, Peter Jay Salzman wrote:
> begin Ken Bloom <kabloom@ucdavis.edu>
> >
> > On 2003.05.03 18:06, Peter Jay Salzman wrote:
> > >
> > >well, let's say i want to boot a knoppix CD (which would've really
> > >have
> > >been helpful).  how would i go about doing that?  something like
> > >
> > >dd if=/dev/hdd of=/dev/fd0 count=something?
> > >
> >
> > dd if=/cdrom/KNOPPIX/boot.img of=/dev/fd0
> 
> so i guess dd stops automatically without printing an error message
> when the output file has no more space left, but the input file still
> has 649MB left to go?

Please note that I'm not copying from the device file. I'm copying from 
a regular file on the CDROM that the cdrom filesystem has marked as the 
boot image. /cdrom/KNOPPIX/boot.img is a floppy-disk sized file. dd 
will stop when it runs out of input.

> > and FYI, since apparently the boot image can have any name, this the
> 
> > `file` output looks like for the boot image, so you can find it if
> you
> > can't tell by the name.
> >
> > [bloom@kabloom KNOPPIX]% file boot.img
> > boot.img: x86 boot sector, code offset 0x3c, OEM-ID "SYSLINUX", FAT
> 1,
> > root entries 16, sectors 2880 (volumes <=32 MB) , sectors/FAT 9,
> serial
> > number 0x3e2987b9, label: "           ", FAT (12 bit)
> >
> > (if you're actually going to use KNOPPIX, I suggest using the
> boot-en.
> > img boot image, and not the boot.img image as I'm not sure what
> > language boot.img will boot you into.)
> 
> i feel this is a stupid question, but if you create a floppy with
> 
>    dd if=/cdrom/KNOPPIX/boot.img of=/dev/fd0
> 
> and boot off the floppy, the rest of the boot will take place off the
> CD?  how does the boot loader know to start reading data off a
> different
> device?
> 

I'm not sure how it does it. (And I haven't experimented with it either 
to ensure that it really works. I'll take Mark Kim's word for it.)

-- 
I usually have a GPG digital signature included as an attachment.
If you don't know what it is, either ignore it or visit www.gnupg.org
Fingerprint: D5E2 8839 6ED3 3305 805C  941F 9476 A9BD E2B2 CAD1
The key is keyID E2B2CAD1 on pgp.mit.edu