Compression used in .wim (Vista) images

[jaclaz]

Hallo to everybody.

I am looking for some help/hints/ideas about the so-called "XPRESS" compression that can be used (as opposed to LZX one) when creating .wim images.

Over at boot-land:
http://www.boot-land.net
member booty#1 has begun writing an independent Open Source/Freeware tool to manage .wim images:
http://www.boot-land.net/forums/inde...topic=5308&hl=

The project is (will be) hosted on sourceforge:
http://sourceforge.net/projects/wimtool/
http://wimtool.wiki.sourceforge.net/Compression

We are having problems with the compression used.

The idea that "XPRESS" is actually another name for "LZNT1" compression appears to be not accurate.

ANY, and I mean ANY help, links, docs, code, whatever on the matter the members of the encode.su board may be able to give will be greatly appreciated.

If you do not want to register at boot-land, reply here and I will point booty#1 to the relevant info.

Thanks to all in advance.

jaclaz

[maadjordan]

7-zip supports wim but i think the lzx mode .. please provide samples of lznt1 so igor may interact with you

[jaclaz]

Thank you, maadjordan.

I am attaching the same three files posted in the original thread on boot-land.
They are the lgpl.txt file put inside a .wim with the three available compressions:
test_none.wim (NO compression)
test_maximum.wim (LZX Compression, 7-zip compatible)
test_fast.wim (Fast or "XPRESS" compression)

The first two are NOT a problem, first one is non-compressed and second one is documented.

As mentioned in the referenced thread, the dd for windows (FAU) edition has internal support for both lznt1 and lznt1+ (whatever the latter may be).
http://gmgsystemsinc.com/fau/

The lznt1 compression appears to be the same, or very similar, to that used natively by 2K/XP/2003 and maybe Vista on NTFS compressed volumes, but it does not resembles at all to the one used in test_fast.wim.

There is a Commercial tool, Winmount:
http://www.winmount.com/
that is capable of mounting the "XPRESS" compressed images allright, besides the LZX ones.

We are looking for any info on the algorithm used and, also, for any suggestion about existing compression/decompression libraries that could already have them or that however being open-source could be modified as to include the two algorithms.

jaclaz

[maadjordan]

strange 7-zip in its srouces support "copy" & "Lzx" method but the "lzx" work only.. i have informed Igor maybe it can be solved easily..

[jaclaz]

Smallish update.

It seems like the XPRESS algorithm is used somewhere else (network protocols) and it is called "Win2K3".
More details on original thread on boot-land.

Still, if anyone has any suggestion about handy compression/decompression libraries, I would be grateful.

jaclaz

[maadjordan]

based on igor result he could support the xpress algorithem but mor examples is required to check..

"Hello!

I suppose I can decompress wim/Xpress now.
But I need more files for test (with bigger embedded files).
Do you have them?
I have no wim creating tool and vista installed now.
So I can't create examples myself.

Igor"

[maadjordan]

it confirmed 7-zip v4.59 supports all methods (including Xpress)

[pat357]

it confirmed 7-zip v4.59 supports all methods (including Xpress)

7z.exe/7z.dll do support wim, but 7za apparently does not.

[hastert]

http://msuiche.net/con/bhusa2008/Win...profit-0.6.pdf

And this link too: http://www.msuiche.net/2008/04/06/fe...ty-initiative/

I suggest you to read this talk. There is a part about Xpress algorithm.

[jaclaz]

Sorry for the late reply.

Thank you very much all, hastert for the given links and maadjordan and pat357 for the news about 7-zip.

I'll pass the info on to booty#1 over at boot-land.

jaclaz