Booting Linux from USB

[rog]

OK.  I know little.   However.  Puppy Linux is designed to boot from 
USB.  They also have a boot floppy to assist in booting from USB when 
unusual problems occur.  Maybe you can find something useful in the 
Puppy Linux Forum.   http://www.murga-linux.com/puppy/

Derek Davis wrote:
> I'm trying to get Linux booting off of a USB thumb drive.  I tried 
> both using
> image.squashfs (which would be my preferred method) and just putting
> the whole, uncompressed file system on the USB drive.  I can get the
> system to load the kernel and begin booting using either method, but
> the problem happens when it actually tries to access the file system.
>
> When I use squashfs, the kernel goes through it's initialization, and
> then it begins looking for the device that has image.squashfs.  It
> checks sda (my sata hard drive) and hda (my optical drive), but it
> doesn't check sdb, which is my USB drive.  However, it then drops me
> to busy box, and from there I can mount /dev/sdb1, point the env var
> LOOP to it, exit, and it boots fine.
>
> When I copy the whole file system to the USB drive and modify menu.lst
> accordingly, I'm not sure how to set the root= parameter, because I
> need to set it to sdb, whereas if someone doesn't have a sata drive,
> they would need it set to sda.  None the less, for the sake of
> testing, I set it to sdb.  After the kernel init, it says that
> /dev/sdb1 is not a valid root device.  It then immediately prompts me
> to specify a boot device, so I put /dev/sdb1 exactly as in the
> menu.lst, and it works.
>
> So, how can I get this working?  Any suggestions?  Basically, why
> won't the system check my USB drive for the image.squashfs file, even
> though from busy box I can mount and use it?  I made sure that USB
> drivers are compiled into the kernel and not modules.  And why, when
> using the uncompressed file system, can the system not use /dev/sdb1
> until I specify it after it fails?  I've been searching the web, but
> can't find anything helpful.
>
> Thanks.
>