3 This is wimlib version 1.6.0 (January 2014). wimlib is a C library for
4 creating, modifying, extracting, and mounting files in the Windows Imaging
5 Format (WIM files). These files are normally created using the ImageX
6 (imagex.exe) or Dism (Dism.exe) utilities on Windows, but wimlib is distributed
7 with a free implementation of ImageX called "wimlib-imagex" for both UNIX-like
12 To install wimlib and wimlib-imagex on Windows you simply need to download and
13 extract the ZIP file containing the latest binaries from the SourceForge page
14 (http://sourceforge.net/projects/wimlib/), which you may have already done.
16 To install wimlib and wimlib-imagex on UNIX-like systems (with Linux being the
17 primary supported and tested platform), you must compile the source code, which
18 is also available at http://sourceforge.net/projects/wimlib/. Alternatively,
19 check if a package has been prepared for your Linux distribution. Example files
20 for Debian and RPM packaging are in the debian/ and rpm/ directories.
24 A Windows Imaging (WIM) file is an archive designed primarily for archiving
25 Windows filesystems. However, it can be used on other platforms as well, with
26 some limitations. Like some other archive formats such as ZIP, files in WIM
27 archives may be compressed. WIM files support multiple compression formats,
28 including LZX, XPRESS, and LZMS. All these formats are supported by wimlib.
30 A WIM file consists of one or more "images". Each image is an independent
31 top-level directory structure and is logically separate from all other images in
32 the WIM. Each image has a name as well as a 1-based index in the WIM file. To
33 save space, WIM archives automatically combine all duplicate files across all
36 A WIM file may be either stand-alone or split into multiple parts. Split WIMs
37 are read-only and cannot be modified.
41 wimlib itself is a C library, and it provides a documented public API (See:
42 http://wimlib.sourceforge.net) for other programs to use. However, it is also
43 distributed with a command-line program called "wimlib-imagex" that uses this
44 library to implement an imaging tool similar to Microsoft's ImageX.
45 wimlib-imagex supports almost all the capabilities of Microsoft's ImageX as well
46 as additional capabilities. wimlib-imagex works on both UNIX-like systems and
47 Windows, although some features differ between the platforms.
49 Run `wimlib-imagex' with no arguments to see an overview of the available
50 commands and their syntax. For additional documentation:
52 * If you have installed wimlib-imagex on a UNIX-like system, you will find
53 further documentation in the man pages; run `man wimlib-imagex' to get
56 * If you have downloaded the Windows binary distribution, you will find the
57 documentation for wimlib-imagex in PDF format in the "doc" directory,
58 ready for viewing with any PDF viewer. Please note that although the PDF
59 files are converted from UNIX-style "man pages", they do document
60 Windows-specific behavior when appropriate.
64 wimlib (and wimlib-imagex) can create XPRESS, LZX, or LZMS compressed WIM
65 archives. The following tables compare the compression ratio and performance
66 for creating a compressed x86_64 Windows PE image with XPRESS and LZX. Note:
67 these timings were done on Windows so that the times would be fully comparable;
68 however, wimlib may have even better performance on other operating systems such
69 as Linux. Timings were done with 2 CPUs available, both of which automatically
70 are used by wimlib for both XPRESS and LZX, and also by imagex.exe but
71 apparently only for LZX.
75 XPRESS Compression LZX Compression
76 wimlib-imagex (v1.5.3): 207,444,390 bytes 188,106,091 bytes
77 Microsoft imagex.exe (Windows 7): 209,960,209 bytes 188,224,481 bytes
79 Table 2. Time to create WIM
81 XPRESS Compression LZX Compression
82 wimlib-imagex (v1.5.3): 73 sec 202 sec
83 Microsoft imagex.exe (Windows 7): 90 sec 149 sec
85 The above LZX data are using explicitly specified maximum compression
86 ('--compress=maximum') as of wimlib v1.5.3. If `wimlib-imagex capture' or
87 `wimlib-imagex capture' is instead run with no '--compress' argument, then a
88 faster LZX compressor is used; it will produce results in between those given
89 for XPRESS and LZX above.
91 Note: if the absolute maximum but still compatible (i.e. not changing the
92 compression chunk size) LZX compression ratio is desired, `wimlib-imagex
93 optimize WIMFILE --recompress --compress-slow' on one of the above
94 LZX-compressed WIMs produces a WIM of 187,089,943 bytes in about 400 seconds.
98 WIM images may contain data, such as alternate data streams and
99 compression/encryption flags, that are best represented on the NTFS filesystem
100 used on Windows. Also, WIM images may contain security descriptors which are
101 specific to Windows and cannot be represented on other operating systems.
102 wimlib handles this NTFS-specific or Windows-specific data in a
103 platform-dependent way:
105 * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
106 Windows-specific data are supported natively.
108 * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
109 Windows-specific data are ordinarily ignored; however, there is also special
110 support for capturing and extracting images directly to/from unmounted NTFS
111 volumes. This was made possible with the help of libntfs-3g from the
114 For both platforms the code for NTFS capture and extraction is complete enough
115 that it is possible to apply an image from the "install.wim" contained in recent
116 Windows installation media (Vista, Windows 7, or Windows 8) directly to a NTFS
117 filesystem, and then boot Windows from it after preparing the Boot Configuration
118 Data. In addition, a Windows installation can be captured (or backed up) into a
119 WIM file, and then re-applied later.
123 A major use for wimlib and wimlib-imagex is to create customized images of
124 Windows PE, the Windows Preinstallation Environment, on either UNIX-like systems
125 or Windows without having to rely on Microsoft's software and its restrictions
128 Windows PE is a lightweight version of Windows that can run entirely from memory
129 and can be used to install Windows from local media or a network drive or
130 perform maintenance. It is the operating system that runs when you boot from
131 the Windows installation media.
133 You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
134 Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
135 Windows Automated Installation Kit (WAIK), which is free to download from
136 Microsoft, inside the `WinPE.cab' file, which you can extract natively on
137 Windows, or on UNIX-like systems if you install either the `cabextract' or
140 In addition, Windows installations and recovery partitions frequently contain a
141 WIM containing an image of the Windows Recovery Environment, which is similar to
144 A shell script `mkwinpeimg' is distributed with wimlib on UNIX-like systems to
145 ease the process of creating and customizing a bootable Windows PE image.
149 This section documents the dependencies of wimlib and the programs distributed
150 with it, when building for a UNIX-like system from source. If you have
151 downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
152 dependencies were already included and this section is irrelevant.
155 This is a commonly used free library to read and write XML files. You
156 likely already have it installed as a dependency for some other program.
157 For more information see http://xmlsoft.org/.
159 * libfuse (optional but highly recommended)
160 Unless configured with --without-fuse, wimlib requires a non-ancient
161 version of libfuse to be installed. Most Linux distributions already
162 include this, but make sure you have the libfuse package installed, and
163 also libfuse-dev if your distribution distributes header files
164 separately. FUSE also requires a kernel module. If the kernel module
165 is available it will automatically be loaded if you try to mount a WIM
166 file. For more information see http://fuse.sourceforge.net/. FUSE is
167 also available for FreeBSD.
169 * libntfs-3g (optional but highly recommended)
170 Unless configured with --without-ntfs-3g, wimlib requires the library
171 and headers for libntfs-3g version 2011-4-12 or later to be installed.
172 Versions dated 2010-3-6 and earlier do not work because they are missing
173 the header xattrs.h (and the file xattrs.c, which contains functions we
174 need). libntfs-3g version 2013-1-13 is compatible only with wimlib
177 * OpenSSL / libcrypto (optional)
178 wimlib can use the SHA1 message digest code from OpenSSL instead of
179 compiling in yet another SHA1 implementation. (See LICENSE section.)
183 * syslinux (optional)
184 * cabextract (optional)
185 The `mkwinpeimg' shell script will look for several other programs
186 depending on what options are given to it. Depending on your Linux
187 distribution, you may already have these programs installed, or they may
188 be in the software repository. Making an ISO filesystem requires
189 `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
190 requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
191 (http://www.syslinux.org). Retrieving files from the Windows Automated
192 Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
196 This section documents the most important options that may be passed to the
197 "configure" script when building from source:
200 If libntfs-3g is not available or is not version 2011-4-12 or later,
201 wimlib can be built without it, in which case it will not be possible to
202 apply or capture images directly to/from NTFS volumes.
205 If libfuse or the FUSE kernel module is not available, wimlib can be
206 compiled with --without-fuse. This will remove the ability to mount and
210 Build in functions for SHA1 rather than using external SHA1 functions
211 from libcrypto (part of OpenSSL). The default is to use libcrypto if it
212 is found on the system.
214 --enable-xattr, --disable-xattr
215 Enable or disable support for the extended-attributes interface to NTFS
216 alternate data streams in mounted WIMs. To support these, wimlib
217 requires that the setxattr() function and the attr/xattr.h header are
218 available. The default is to autodetect whether support is possible.
220 --disable-multithreaded-compression
221 By default, data will be compressed using multiple threads when writing
222 a WIM, unless only 1 processor is detected. Specify this option to
223 disable support for this.
226 Use a very fast assembly language implementation of SHA1 from Intel.
227 Only use this if the build target supports the SSSE3 instructions.
229 --disable-error-messages
230 Save some space by removing all error messages from the library.
233 Remove assertions included by default.
237 wimlib has primarily been tested on Linux and Windows (primarily Windows 7, but
238 also Windows XP and Windows 8).
240 wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
241 you do not have libntfs-3g 2011-4-12 or later available, you must configure
242 wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
243 load the POSIX message queue module (run `kldload mqueuefs').
245 The code has primarily been tested on x86 and x86_64 CPUs, but it's written to
246 be portable to other architectures and I've also tested it on ARM. However,
247 although the code is written to correctly deal with endianness, it has not yet
248 actually been tested on a big-endian architecture.
252 The WIM file format is partially specified in a document that can be found in
253 the Microsoft Download Center. However, this document really only provides an
254 overview of the format and is not a formal specification.
256 With regards to the supported compression formats:
258 - Microsoft has official documentation for XPRESS that is of reasonable quality.
259 - Microsoft has official documentation for LZX but it contains errors.
260 - There does not seem to be any official documentation for LZMS, so my comments
261 and code in src/lzms-decompress.c may in fact be the best documentation
262 available for this particular compression format.
264 The code in ntfs-3g_apply.c and ntfs-3g_capture.c uses the NTFS-3g library,
265 which is a library for reading and writing to NTFS filesystems (the filesystem
266 used by recent versions of Windows). See
267 http://www.tuxera.com/community/ntfs-3g-download/ for more information.
269 The LZX decompressor (lzx-decompress.c) was originally based on code from the
270 cabextract project (http://www.cabextract.org.uk) but has been rewritten.
272 The LZX compressor (lzx-compress.c) was originally based on code written by
273 Matthew Russotto (www.russotto.net/chm/) but has been rewritten. It now uses
274 suffix array construction code from divsufsort
275 (https://code.google.com/p/libdivsufsort/) and algorithms from 7-Zip as well as
276 several published papers.
278 lz_hash.c contains a hash-table-based LZ77 matchfinder that is based on code
279 from zlib but has been rewritten. This code is applicable to XPRESS, LZX, and
280 LZMS, all of which are partly based on LZ77 compression.
282 A limited number of other free programs can handle some parts of the WIM
285 * 7-zip is able to extract and create WIMs (as well as files in many
286 other archive formats). However, wimlib is designed specifically to handle
287 WIM files and provides features previously only available in Microsoft's
288 implementation, such as the ability to mount WIMs read-write as well as
289 read-only, the ability to create LZX or XPRESS compressed WIMs, and the
290 correct handling of security descriptors and hard links.
291 * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
292 provides similar capabilities to wimlib-imagex. One thing to note, though,
293 is that it does not support compression and decompression by itself, but
294 instead relies on external native code, such as the codecs from wimlib.
296 A very early version of wimlib is being used to deploy Windows 7 from the
297 Ultimate Deployment Appliance. For more information see
298 http://www.ultimatedeployment.org/.
300 If you are looking for a UNIX archive format that provides features similar to
301 WIM, I recommend you take a look at SquashFS (http://squashfs.sourceforge.net/).
305 As of version 1.0.0, wimlib and all programs and scripts distributed with it are
306 released under the GNU GPL version 3.0 or later.
308 wimlib is independently developed and does not contain any code, data, or files
309 copyrighted by Microsoft. It is not known to be affected by any patents.
311 On UNIX-like systems, if you do not want wimlib to be dynamically linked with
312 libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
313 implementation with built-in code and there will be no difference in
318 wimlib comes with no warranty whatsoever. Please submit a bug report (to
319 ebiggers3@gmail.com) if you find a bug in wimlib and/or wimlib-imagex.
321 Be aware that some parts of the WIM file format are poorly documented or even
322 completely undocumented, so I've just had to do the best I can to read and write
323 WIMs that appear to be compatible with Microsoft's software.
git://wimlib.net / wimlib / blob