Few questions about sanhook'ing and BIOS

[mr_jrt]

I'll start by thanking you all for iPXE. I've only recently discovered it, and it seems pretty awesome. So thanks for that.

Apologies if I've missed something obvious, this is all new territory for me. Basically, I'm learning about with iSCSI by tinkering with it, and my weapons of choice are the latest iPXE ISO, a simple iSCSI server from here, and Microsoft's iSCSI bootable initiator in XP setup, booted from an ISO on a USB stick using Firadisk.

As you might expect with such a convoluted setup, I have a weird problem. (I'm not looking for help for the XP bit here - I'm just telling you for context.)

Basically, the install seems to work, it formats, but tries to add the MBR to my USB stick rather than the iSCSI target, and when looking at the resulting VHD I end up with a full directory tree, but not a single file. All a bit weird. So, troubleshooting 101, I took a step back.

I wanted to see if the device was working in anything else. So I tried a partedmagic boot ISO, and was able to mount the iSCSI target fine, and dump files on it, etc. no problems. So, step back.

I boot XP setup from GRUB4DOS, which has a command line. So I fired that up, and had a look at what GRUB could see via the BIOS. At this point, I get an error from GRUB4DOS that it's "tuning" the geometry of the iSCSI sanhook'ed disk, and then showing it as a CHS drive, not LBA. I suspect this may be incorrect hooks into int13 by iPXE? (btw, the target is a 10GB VHD on my other machine.)

I'm going to try using a smaller VHD (< 8GB to avoid the CHS limit) to see if that helps, but thought I may as well ask here if this is a known limitation or if I'm doing something obviously silly here to someone who is a bit more experienced.

[mcb30]

(2016-03-06 04:20)mr_jrt Wrote:  I boot XP setup from GRUB4DOS, which has a command line. So I fired that up, and had a look at what GRUB could see via the BIOS. At this point, I get an error from GRUB4DOS that it's "tuning" the geometry of the iSCSI sanhook'ed disk, and then showing it as a CHS drive, not LBA. I suspect this may be incorrect hooks into int13 by iPXE? (btw, the target is a 10GB VHD on my other machine.)

I'm going to try using a smaller VHD (< 8GB to avoid the CHS limit) to see if that helps, but thought I may as well ask here if this is a known limitation or if I'm doing something obviously silly here to someone who is a bit more experienced.

Whatever the problem is, it's not that. iPXE supports LBA via the usual INT13 extensions.

Michael

[mr_jrt]

Indeed. It dawned on me an hour or so after I posted that (sorry - was unable to edit before bothering anyone with it!) that my raid controller was still active and could be interfering...so I pulled it, and the phantom drives vanished.

So good in some ways, but does mean that G4D cannot see the iPXE SAN drive though, which is something I refocussed on in my follow-up thread: http://forum.ipxe.org/showthread.php?tid...8#pid12368