[syslinux] memdisk and winxp boot disk

Roy Badami roy.badami at globalgraphics.com
Wed Jun 19 09:14:17 PDT 2002


 > > I don't think that's it.  I'm pretty sure that NT uses the BIOS to
 > > read the floppy; the file it's failing to load is from the hard disk
 > > of the machine (which would normally also be read via the BIOS).
 > > 
 > 
 > Shouldn't it be trying to read it from the floppy?


If Giulio is describing the technique I'm familiar with from NT (and a
cursory look at the microsoft web page suggests he is) then it's not
actually a bootable NT floppy (I don't believe there's any documented
way to build a bootable NT system on a floppy, though the NT installer
*does* actually boot a minimal NT system from floppy.)

What we're talking about is a standard disaster recovery technique for
NT and derivatives which can be used when the NT boot sector or boot
loader is damaged.

What you do is you place the first stage boot loader (ie the boot
sector and the files NTLDR and NTDETECT.COM) -- which would normally
live on the hard disk -- on a floppy instead.  You also place a copy
of the BOOT.INI file there; this tells the boot loader where to find
the NT system partition (which even in a hard disk boot needn't be the
same partition as the boot partition).

The kernel is *not* on the floppy, it is loaded perfectly normally
from the hard disk partition referenced by the BOOT.INI file.

Normally, the boot loader uses INT 13 to load the NT kernel from hard
disk, though it is possible (but extremely rare) in SCSI
configurations to have the boot loader load an additional device
driver file and then bootstrap the kernel by accessing the SCSI card
directly.

The BOOT.INI file that Guilio is using instructs the boot loader to
use the BIOS to load a kernel and other associated files from the
\WINDOWS directory tree on the first partition of the first hard disk.

	-roy



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