[ipxe-devel] HP Blade Support

Michael Brown mbrown at fensystems.co.uk
Sat Mar 19 12:35:03 UTC 2011

On Friday 18 Mar 2011 20:07:43 Andrew Bobulsky wrote:
> There's a setup log buried deep in the "Panther" folder on the RAM
> drive WinPE uses that will contain diagnostic info, but I found out
> (after days of pulling my hair out!) that this is [usually] an issue
> with resolving ARC paths to NT Device names.  All of my info/research
> is in a technet thread where I mostly talked to myself.... but it may
> be of use to you if you want to go in-depth on this problem:
> http://social.technet.microsoft.com/Forums/en-US/w7itproinstall/thread/cea6
> 177e-9cb2-420e-bbc0-0cac487e51e2

For what it's worth: I have previously single-stepped through the portions of 
the Windows kernel that deal with assigning ARC paths.  To the best of my 
knowledge, the way it works is that:

a) NTLDR (or equivalent in newer Windows versions) uses INT13 to enumerate the 
BIOS drives within the system, and to read the boot sector of each drive.  It 
records the 32-bit signature of each disk.

b) Sometime shortly after the last boot driver has completed initialisation, 
Windows will scan through all native drives that it knows about, checking the 
signature from the boot sector of each drive.  It will create ARC path 
symlinks if and when it finds a match against the disk signatures previously 
obtained via INT13.

The most reliable method that I am currently aware of is to use WDS or any 
similar deployment product (e.g. Altiris RDP) that allows WinPE to be loaded 
over the network *without* having to create an extra BIOS drive (CD-ROM or 
otherwise) just to load WinPE.  Doing it this way means that nothing gets a 
chance to interfere with the INT13 drive mappings before Windows comes in and 
uses INT13 to read the disk signatures.

There's a walkthrough of using WDS to install directly to an iSCSI target at 
http://ipxe.org/howto/wds_iscsi if that helps at all.  It should apply just as 
well to any similar deployment mechanism that loads WinPE via TFTP.


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