[syslinux] USB question

Rich Mahn rich at lat.com
Wed Apr 12 13:55:15 PDT 2006

Thanks.  This is pretty much what I suspected.
If it were Linux I wanted on the USB drive, I know how to
do it using the kernel and initrd.  Unfortunately its Windows XP.
I'm not even sure what is the Windows equivalent of a kernel,
much less how it loads disk drivers.


>>> "Nazo" == Nazo  <nazosan at gmail.com> writes:

  Nazo> On 4/12/06, Rich Mahn <rich at lat.com> wrote:
  >> The BIOS on my laptop does not support booting from USB.  I would
  >> like to be able to have my Windows XP on a partition on a USB
  >> disk drive and be able to run from the USB disk using perhaps a
  >> CD or floppy to bootstrap the system.  My questions: 1). Is there
  >> a way to use syslinux and friends to do this?  2). If not, is
  >> there some other boot loader that may work?  3). Is there any
  >> hope at all?
  >> Rich
  Nazo> 1.  Syslinux relies on the BIOS to handle actually accessing
  Nazo> the USB/etc.  I can't imagine any way in which it could manage
  Nazo> to do what the BIOS can't in this particular respect.

  Nazo> 2.  I'm pretty sure they all have the same problem.  However,
  Nazo> some like Lilo us a lot of the linux stuff from the system you
  Nazo> actually install on.  I don't know what would happen if you
  Nazo> tried to trick it into working somehow, but, who knows, maybe
  Nazo> it's worth a go?

  Nazo> 3.  Well, there's another more indirect way that some do,
  Nazo> especially with live boot discs.  They load up a kernel +
  Nazo> initrd with USB support and then proceed to mount USB drives
  Nazo> looking for the rest of their data.  Almost all live distros
  Nazo> that support booting from a USB drive at all do it this way I
  Nazo> think.  I know all the ones I've used do.  It's pretty tough
  Nazo> to do this with a floppy.  You usually have to split it up
  Nazo> with the kernel on one disc and the initrd on another.  I
  Nazo> never studied how this was done since back then I didn't use
  Nazo> linux much and today I can't even retain a functional floppy
  Nazo> drive more than a few weeks before it tears up.  HOWEVER, I
  Nazo> suspect the way this is done is it first loads an absolutely
  Nazo> minimal ramdrive with nothing extra but support for /dev/fd0
  Nazo> and a simple init script which loads up a real ramdrive from
  Nazo> the next floppy.  If you use a CD this should be easy to do
  Nazo> via the live distro method since space isn't an issue.
  Nazo> However, if you're going to use a CD, what you should probably
  Nazo> do is set it up so that it only uses the USB drive for things
  Nazo> that change who's changes you need to retain across reboots.
  Nazo> No need to throw the entire filesystem on there after all.

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