[gPXE] 512MB Limitation of gPXE ?

[Shao Miller]

Good day, guy.

Your config-file LABEL doesn't seem right.  The LABEL should reflect the
name of the item that you are booting.  You have already booted gpxelinux.0
and it is gpxelinux.0 that reads the config-file, so "LABEL gpxelinux"
doesn't make a lot of sense.  I'd suggest using "LABEL winxp", since that is
what you are booting from gpxelinux.0.

Back to your problem, is there any reason why you are not using MEMDISK,
instead of GRUB4DOS?  Please try it and see if there's any difference:

  LABEL winxp
    KERNEL http://192.168.100.254/memdisk
    INITRD http://192.168.100.254/MiniXP350.vhd
    APPEND raw

Also note that "Later, grub.exe will map the vhd image into memory" is
incorrect.  gpxelinux.0 is the program that maps the VHD into memory in your
current scenario.  GRUB4DOS establishes a very simple mapping of BIOS drive
0x80 to the already-mapped VHD image.

Also: Why are you calling your image a VHD?  If it can be booted by GRUB4DOS
in the way that you've described, the image is basically just a
sector-by-sector disk image.  There's no need to confuse things by calling
it a VHD.

- Shao Miller

________________________________________
From: gpxe-bounces at etherboot.org [mailto:gpxe-bounces at etherboot.org] On
Behalf Of LinuxByExamples
Sent: Thursday, October 18, 2012 09:04
To: gpxe at etherboot.org
Subject: [gPXE] 512MB Limitation of gPXE ?

Hi, 

This is the first time I use this mailing list, so I am very sorry if I have
made any mistake.

Well, here is my case, I have followed this post
: http://www.linuxbyexamples.net/2012/08/boot-winxp-from-http-server.html

_ I can use gPXE to download two files : grub.exe and winxp.vhd image by
http. Later, grub.exe will map the vhd image into memory then successfully
load the windows xp. The config file look this :

LABEL gpxelinux
kernel http://192.168.100.254/grub.exe
initrd http://192.168.100.254/MiniXP350.vhd
APPEND --config-file="map (rd)+1 (hd0); map --hook; chainloader
(hd0,0)/ntldr"

This works very well.

_ But when the winxp.vhd image becomes bigger than 512MB ( I added some more
files and winxp modules into to the image), the loading step fire an error
tell me that the image can not be loaded ... I then try put the bigger vhd
image and grub.exe into usb disk and I can boot it well (without using gPXE
http loading). So, I guess the problem is in gPXE module, it looks like that
gPXE can not load the image bigger than 512MB ? is this right or I have
missed something else ?

I hope you can help to overcome this limitation.

Thank you guy.