Grub4Dos, Basic links and WHERETO... External links Options

[Nuno Brito]

from http://grub4dos.sourceforge.net/

Besides the grub shell in real mode, GRUB for DOS have other innovations. Such as GRLDR, which is the grub console loadable by NT boot manager. Also, there is disk simulation function, which would enable you to treat an image file as floppy/harddisk (it hooks INT13 to do the magic, therefore, it works in systems that honor INT13 drives, this includes all sorts of dos, and in some case, Windows 9X). GRUB for DOS also incorporates some patches to make it more useful. This includes the NTFS patch, which enables grub to access NTFS partitions, and also the findroot patch, which makes it possible to find MENU.LST dynamically, etc.

Advantages:

* Can be launched by NTLDR
* Can be launched from linux with kexec
* Can create ramdisks
* Can use file as well as partition as the source of the ramdisk
* Can be used as a no-emulation-mode bootable CD-ROM boot image
* Has a "Chinese" special build that can display chinese help message at the console
* Add device (md) that can map a specified range of memory as a ramdisk
* Add device (rd) that reflect the memdisk loaded by inited
* Can chainload KERNEL.SYS from FreeDOS
* Can chainload NTLDR from Windows NT/2K/XP
* Can chainload IO.SYS from MSDOS, Windows 95/98/ME

Grub4Dos is a good start point for projects that target special boot projects, here's a couple of links with more informations:

http://grub4dos.sourceforge.net/
http://grub4dos.sourceforge.net/grub4dos_examples.html
http://freshmeat.net/projects/grub4dos/

UPDATE 20/01/2009:

http://grub4dos.jot.com/WikiHome - NO MORE:
New site(s):
http://sites.google.com/site/grubdos/
http://nufans.net/grub4dos/
Old releases here:
http://nufans.net/grub4dos/history/

[was_jaclaz]

As it already happened to mismatch info posted with actual version of GRUB4DOS, here is the
WHERETO
FINAL VERSIONS are here:
http://sourceforge.net/projects/grub4dos

example version 0.4.1
http://prdownloads.sourceforge.net/grub4do....1.zip?download


STABLE PRE-RELEASE VERSIONS are here:
http://sarovar.org/projects/grub4dos/

example version 0.4.2pre6
http://sarovar.org/download.php/1048/grub_...s-0.4.2pre6.zip


ALL NEWISH, I would call'em "experimental features" or "night builds", are posted on the wiki here:

UPDATE 20/01/2009:

http://grub4dos.jot.com/WikiHome - NO MORE:
New site:
http://sites.google.com/site/grubdos/

Old releases here:
http://nufans.net/grub4dos/history/

a server with latest-latest versions is here:
http://nufans.net/grub4dos/

example 2009-01-20
http://nufans.net/grub4dos/grub4dos-0.4.4-2009-01-20.zip

Unless otherwise stated all comments, hints, howto etc., will always be related to the NEWISH experimental version.


a server with latest "stablish/newish" versions is here:
https://gna.org/projects/grub4dos/


A newish version of GUI for grubinst has been written by our member booty #1:
http://www.boot-land.net/forums/index.php?...ic=6466&hl=
Download from here:
http://exec-se.de/WinBuilder/Downloads/grubinst_gui.zip

jaclaz

[ktp]

> Can be used as a no-emulation-mode bootable CD-ROM boot image

What does it mean? Does it mean grub4dos can directly boot an .iso file stored on the USB key (like bcdw 2.01) ?

[ktp]

OK the answer is no. The function is different as stated in grub4dos readme.txt.

--- Excerpt:
Update 5: Now GRLDR can be used as a no-emulation-mode bootable CD-ROM
boot image. Example for Linux users:

mkdir iso_root
cp grldr iso_root
mkisofs -R -b grldr -no-emul-boot -boot-load-seg 0x1000 -o bootable.iso iso_root

Note: There are quite a lot of buggy BIOSes that cannot boot
the CD-ROM made with bootable.iso. The boot image of
bootable.iso is the whole GRLDR file, not solely the first
2048 bytes of GRLDR. Buggy BIOSes only load the beginning
2048 bytes of the boot image, and will hang the machine. For
Those buggy BIOSes, please use stage2_eltorito instead.
Do a compilation, and the stage2_eltorito will be created in
the grub-0.97/stage2/ directory. For detailed usage about
stage2_eltorito, google the Internet, please. Don't use the
above `mkisofs' line on stage2_eltorito. The line only works
for GRLDR. The stage2_eltorito has a different `mkisofs' line
as in the following:

mkdir iso_root
cp stage2_eltorito iso_root
mkisofs -R -b stage2_eltorito -no-emul-boot -boot-load-size 4 -boot-info-table -o stage2.iso iso_root

The option -boot-info-table should not be used with the GRLDR
line, while it must be used with stage2_eltorito.

Update 2006-12-03: Now grldr can be used the same way as
stage2_eltorito. The -boot-info-table option is allowed but you
can omit it:

mkdir iso_root
cp grldr iso_root
mkisofs -R -b grldr -no-emul-boot -boot-load-size 4 -o grldr.iso iso_root

Also note that the bootable.iso above must be created with the
-boot-load-seg 0xHHHH option where HHHH is greater than or
equal to 1000(hex). If HHHH < 1000(hex), QEMU will hang. This
is a bug in QEMU. The grldr.iso can be created with or without
-boot-load-seg 0xHHHH option.

[Oleg_II]

New English language page about Grub4DOS is opened here. Tynbit and Bean are often visit this sevrer for discussions in Chinese but now it is possible to post any questions and suggestions in English too

There are two sub-forums right now:

Grub4DOS Mainland
Grub4DOS Project's general discussion: usage, updates, req. etc.

Helper Tools
Helpful tools for grub4dos: grldr.mbr, bootlace, grubinst...

[Moon Goon]

I here GRUB4DOS can boot to floppy disk images. If this can be combined with a floppy made to boot XP http://support.microsoft.com/kb/305595 then we'd finally have a drive neutral way to boot XP or Pre-install Environments.

[was_jaclaz]

sorry, MoonGoon, but you are introducing an (unneeded) complication.
Grub4dos can DIRECTLY chainload either NTLDR or SETUPLDR.BIN, there is no need to chainload a floppy which bootrecord invokes NTLDR (which is actually the flopoy you posted a reference to).
Just as a reference, here is an article that better explains thi kind of floppy (and why everyone should have one of these handy):
http://www.xxcopy.com/xxcopy33.htm

jaclaz

[Moon Goon]

Not trying to argue: just to understand

The Microsoft boot disk I referenced seems to copy a generic NTDLR from the install disc. See step 2.

2. Copy the Ntldr and the Ntdetect.com files from the I386 folder on the Windows XP Setup CD-ROM, Windows XP Setup floppy disk, or from a computer that is running the same version of Windows XP as the computer that you want to access with the boot floppy.

The XXCOPY boot floppy seems to use the old NTLDR off of the hard drive which (I think) is built specifically for that hard drive. See step 3 from your link:

3. XXCOPY16 C:\NTLDR A:\ /H

Maybe I'm thinking of a different system file than NTLDR. *shrugs* I think the BartPE installer has to generate some sort of system file called PELDR that takes some geometry info from the hard drive. Again, I may be wildly off base Maybe NTLDR is generic.

In any case, it would be interesting to see how chainloading a floppy image works in GRUB4DOS. I got lost in the links and couldn't find a proper reference to that feature.

[d4vr0s]

PELDR is actually just setupldr.bin renamed.
NTLDR is not custom built, it's copied directly off the install cd or comes from a hotfix/service pack upgrade.

BOOTSECT.DAT, however, is built from the HD geometry but it's for booting the command console.

This is how I boot a floppy image (gzip compressed)

CODE

title DOS Boot (Grub)
find --set-root /IMAGES/CDBOOT.GZ
map --mem /IMAGES/CDBOOT.GZ (fd0)
map --hook
chainloader (fd0)+1
rootnoverify (fd0)

Compression is not required, it just saves space.

[was_jaclaz]

The ONLY difference between the Microsoft Article and the XXCOPY one is that the latter suggests to prepare the floppy BEFORE you actually lose access to the system, whilst the former gives instructions to create the floppy BECAUSE you have lost the capability to boot, try reading:

2. Copy the Ntldr and the Ntdetect.com files from the I386 folder on the Windows XP Setup CD-ROM, Windows XP Setup floppy disk, or from a computer that is running the same version of Windows XP as the computer that you want to access with the boot floppy.

as

from the computer that is running the same version of Windows XP as the computer that you want to access

or more simply as:

from your computer (that is actually running Windows XP)

PELDR (aka SETUPLDR.BIN) and NTLDR have NO specific geometry, they are programs, i.e. BOOTLOADERS.

Bootsect.dat, on the contrary is a BOOTSECTOR image, and, as such, has the geometry of the drive where it was created.

Here are some more examples of Grub4dos chainloading:
http://www.911cd.net/forums//index.php?sho...=16980&st=5
http://www.911cd.net/forums//index.php?sho...=18231&st=1
http://www.911cd.net/forums//index.php?showtopic=18031

jaclaz