Booting Windows XP using Grub4dos and ramdisk.sys

Hello everyone!

I have a RAW partition (super-floppy) image with Windows XP installed and successfully boot it from RAM using NTLDR and ramdisk.sys. No 3-d party tools are used.

Question: can I compress that image and boot it using Grub4dos or any other tool without installing additional 3-d party drivers?

Edited by snoopy, 26 August 2017 - 01:52 PM.

Hello everyone!

 

I have a RAW partition (super-floppy) image with Windows XP installed and successfully boot it from RAM using NTLDR and ramdisk.sys. No 3-d party tools are used.

 

Question: can I compress that image and boot it using Grub4dos or any other tool without installing additional 3-d party drivers?

Answer:

How are we supposed to know, without knowing EXACTLY what you are doing already?

More or less it should be the one or the other variation of Euhenio's method  

https://web.archive....euhenio.mam.by/

At the time:

http://reboot.pro/to...amboot-booting/

dennis123123 used a NTFS compresed image just fine:

https://web.archive....rt=#entry127683

https://web.archive....rt=#entry127735

If this is the question.

Wonko

Answer:

How are we supposed to know, without knowing EXACTLY what you are doing already?

I have 4 files: boot.ini, ntdetect.com, ntldr and boot.ima, which contains formatted partition with Windows XP (full, not PE).

When all this starting to boot, ntldr writes boot.ima into the RAM and then boots Winbows XP from ramdisk(0). Everything's fine.

Question was: can I reduce the size of boot.ima, using some tools or methods, but without installing additional 3-d party drivers?

I know that Grub4dos can boot lzma, gzip and lz4 images, but how should ntldr deal with that?

I think that at first somebody should unpack boot image into the RAM; then it should hook INT13 and INT15 and start ntldr which will load that image... from RAM to RAM and then boot it. That's bad, since it takes two time more RAM.

P.S.

I was looking at W2k3's ntldr in the hex editor and found there some interesting words: "Unsupported compression format" and "Can't allocate compression buffer". I think it means that W2k3's ntldr supports CAB file compression. But I can be mistaken.

Thank you for trying to help!

What are the contents of boot.ini?

How big (size in bytes) is the .ima?

Is it a partitioned image or just a "supre-floppy" image?

How (exactly) are you booting/loading/chainloading the NTLDR?

(using grub4dos it would be normally possible to move boot.ini, NTLDR and NTDETECT.COM to inside the image)

If the filesystem in the partition is NTFS, you can use, as hinted, compression of NTFS, thus allowing you to make a smaller image.

NTFS compression is not that bad, I doubt that it will be less efficient than gzip, maybe lxma or lz4 may provide some (marginal) advantages in size.

There is also another possibility, using a cab compressed image, in the good ol'days it was possible to use in PE 1.x instead of .iso a cab compressed .is_ image, most probably the same can be done with your full XP but it will use a lot of memory (this is more or less what you just proposed, which is built-in in SETUPLDR.BIN and maybe also in NTLDR):

https://web.archive....showtopic=19737

In the case of the PE there are some possible patches around, see also:

http://reboot.pro/to...-with-grub4dos/

that most probably can be used to modify also a "full XP", but it has to be seen.

Wonko

Posting this just to see if the main page index gets updated (the above post was submitted but the main page index still showed the last post as the one by snoopy).

Please ignore.

EDIT: No it doesn't work.

Wonko

Posting this just to see if the main page index gets updated (the above post was submitted but the main page index still showed the last post as the one by snoopy).

Please ignore.

 

EDIT: No it doesn't work.

 

Wonko

Weird? what is happening lately?

multiple post please delete this
 

Edited by wean_irdeh, 08 September 2017 - 10:47 AM.

multiple post please delete this
 

Edited by wean_irdeh, 08 September 2017 - 10:47 AM.