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 archives.
65 The following tables compare the compression ratio and performance for creating
66 a compressed x86_64 Windows PE image. Note: these timings were done on Windows
67 so that the times would be fully comparable; however, wimlib may have even
68 better performance on other operating systems such as Linux. Timings were done
69 with 2 CPUs available, both of which automatically are used by wimlib for both
70 XPRESS and LZX, and also by imagex.exe but apparently only for LZX. Results for
71 LZMS compression are excluded because the creation of LZMS compressed WIM
72 archives is not yet recommended.
76 XPRESS Compression LZX Compression
77 wimlib-imagex (v1.5.3): 207,444,390 bytes 188,106,091 bytes
78 Microsoft imagex.exe (Windows 7): 209,960,209 bytes 188,224,481 bytes
80 Table 2. Time to create WIM
82 XPRESS Compression LZX Compression
83 wimlib-imagex (v1.5.3): 73 sec 202 sec
84 Microsoft imagex.exe (Windows 7): 90 sec 149 sec
86 The above LZX data are using explicitly specified maximum compression
87 ('--compress=maximum') as of wimlib v1.5.3. If `wimlib-imagex capture' or
88 `wimlib-imagex capture' is instead run with no '--compress' argument, then a
89 faster LZX compressor is used; it will produce results in between those given
90 for XPRESS and LZX above.
92 Note: if the absolute maximum (but still compatible; i.e. not changing the
93 compression chunk size) LZX compression ratio is desired, `wimlib-imagex
94 optimize WIMFILE --recompress --compress-slow' on one of the above
95 LZX-compressed WIMs produces a WIM of 187,089,943 bytes in about 400 seconds.
99 WIM images may contain data, such as alternate data streams and
100 compression/encryption flags, that are best represented on the NTFS filesystem
101 used on Windows. Also, WIM images may contain security descriptors which are
102 specific to Windows and cannot be represented on other operating systems.
103 wimlib handles this NTFS-specific or Windows-specific data in a
104 platform-dependent way:
106 * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
107 Windows-specific data are supported natively.
109 * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
110 Windows-specific data are ordinarily ignored; however, there is also special
111 support for capturing and extracting images directly to/from unmounted NTFS
112 volumes. This was made possible with the help of libntfs-3g from the
115 For both platforms the code for NTFS capture and extraction is complete enough
116 that it is possible to apply an image from the "install.wim" contained in recent
117 Windows installation media (Vista, Windows 7, or Windows 8) directly to a NTFS
118 filesystem, and then boot Windows from it after preparing the Boot Configuration
119 Data. In addition, a Windows installation can be captured (or backed up) into a
120 WIM file, and then re-applied later.
124 A major use for wimlib and wimlib-imagex is to create customized images of
125 Windows PE, the Windows Preinstallation Environment, on either UNIX-like systems
126 or Windows without having to rely on Microsoft's software and its restrictions
129 Windows PE is a lightweight version of Windows that can run entirely from memory
130 and can be used to install Windows from local media or a network drive or
131 perform maintenance. It is the operating system that runs when you boot from
132 the Windows installation media.
134 You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
135 Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
136 Windows Automated Installation Kit (WAIK), which is free to download from
137 Microsoft, inside the `WinPE.cab' file, which you can extract natively on
138 Windows, or on UNIX-like systems if you install either the `cabextract' or
141 In addition, Windows installations and recovery partitions frequently contain a
142 WIM containing an image of the Windows Recovery Environment, which is similar to
145 A shell script `mkwinpeimg' is distributed with wimlib on UNIX-like systems to
146 ease the process of creating and customizing a bootable Windows PE image.
150 This section documents the dependencies of wimlib and the programs distributed
151 with it, when building for a UNIX-like system from source. If you have
152 downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
153 dependencies were already included and this section is irrelevant.
156 This is a commonly used free library to read and write XML files. You
157 likely already have it installed as a dependency for some other program.
158 For more information see http://xmlsoft.org/.
160 * libfuse (optional but highly recommended)
161 Unless configured with --without-fuse, wimlib requires a non-ancient
162 version of libfuse to be installed. Most Linux distributions already
163 include this, but make sure you have the libfuse package installed, and
164 also libfuse-dev if your distribution distributes header files
165 separately. FUSE also requires a kernel module. If the kernel module
166 is available it will automatically be loaded if you try to mount a WIM
167 file. For more information see http://fuse.sourceforge.net/. FUSE is
168 also available for FreeBSD.
170 * libntfs-3g (optional but highly recommended)
171 Unless configured with --without-ntfs-3g, wimlib requires the library
172 and headers for libntfs-3g version 2011-4-12 or later to be installed.
173 Versions dated 2010-3-6 and earlier do not work because they are missing
174 the header xattrs.h (and the file xattrs.c, which contains functions we
175 need). libntfs-3g version 2013-1-13 is compatible only with wimlib
178 * OpenSSL / libcrypto (optional)
179 wimlib can use the SHA1 message digest code from OpenSSL instead of
180 compiling in yet another SHA1 implementation. (See LICENSE section.)
184 * syslinux (optional)
185 * cabextract (optional)
186 The `mkwinpeimg' shell script will look for several other programs
187 depending on what options are given to it. Depending on your Linux
188 distribution, you may already have these programs installed, or they may
189 be in the software repository. Making an ISO filesystem requires
190 `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
191 requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
192 (http://www.syslinux.org). Retrieving files from the Windows Automated
193 Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
197 This section documents the most important options that may be passed to the
198 "configure" script when building from source:
201 If libntfs-3g is not available or is not version 2011-4-12 or later,
202 wimlib can be built without it, in which case it will not be possible to
203 apply or capture images directly to/from NTFS volumes.
206 If libfuse or the FUSE kernel module is not available, wimlib can be
207 compiled with --without-fuse. This will remove the ability to mount and
211 Build in functions for SHA1 rather than using external SHA1 functions
212 from libcrypto (part of OpenSSL). The default is to use libcrypto if it
213 is found on the system.
215 --enable-xattr, --disable-xattr
216 Enable or disable support for the extended-attributes interface to NTFS
217 alternate data streams in mounted WIMs. To support these, wimlib
218 requires that the setxattr() function and the attr/xattr.h header are
219 available. The default is to autodetect whether support is possible.
221 --disable-multithreaded-compression
222 By default, data will be compressed using multiple threads when writing
223 a WIM, unless only 1 processor is detected. Specify this option to
224 disable support for this.
227 Use a very fast assembly language implementation of SHA1 from Intel.
228 Only use this if the build target supports the SSSE3 instructions.
230 --disable-error-messages
231 Save some space by removing all error messages from the library.
234 Remove assertions included by default.
238 wimlib has primarily been tested on Linux and Windows (primarily Windows 7, but
239 also Windows XP and Windows 8).
241 wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
242 you do not have libntfs-3g 2011-4-12 or later available, you must configure
243 wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
244 load the POSIX message queue module (run `kldload mqueuefs').
246 The code has primarily been tested on x86 and x86_64 CPUs, but it's written to
247 be portable to other architectures and I've also tested it on ARM. However,
248 although the code is written to correctly deal with endianness, it has not yet
249 actually been tested on a big-endian architecture.
253 The WIM file format is partially specified in a document that can be found in
254 the Microsoft Download Center. However, this document really only provides an
255 overview of the format and is not a formal specification.
257 With regards to the supported compression formats:
259 - Microsoft has official documentation for XPRESS that is of reasonable quality.
260 - Microsoft has official documentation for LZX but it contains errors.
261 - There does not seem to be any official documentation for LZMS, so my comments
262 and code in src/lzms-decompress.c may in fact be the best documentation
263 available for this particular compression format.
265 The code in ntfs-3g_apply.c and ntfs-3g_capture.c uses the NTFS-3g library,
266 which is a library for reading and writing to NTFS filesystems (the filesystem
267 used by recent versions of Windows). See
268 http://www.tuxera.com/community/ntfs-3g-download/ for more information.
270 The LZX decompressor (lzx-decompress.c) was originally based on code from the
271 cabextract project (http://www.cabextract.org.uk) but has been rewritten.
273 The LZX compressor (lzx-compress.c) was originally based on code written by
274 Matthew Russotto (www.russotto.net/chm/) but has been rewritten. It now uses
275 suffix array construction code from divsufsort
276 (https://code.google.com/p/libdivsufsort/) and algorithms from 7-Zip as well as
277 several published papers.
279 lz77.c contains a hash-table-based LZ77 matchfinder that is based on code from
280 zlib but has been rewritten. This code is applicable to XPRESS, LZX, and LZMS,
281 all of which are partly based on LZ77 compression.
283 A limited number of other free programs can handle some parts of the WIM
286 * 7-zip is able to extract and create WIMs (as well as files in many
287 other archive formats). However, wimlib is designed specifically to handle
288 WIM files and provides features previously only available in Microsoft's
289 implementation, such as the ability to mount WIMs read-write as well as
290 read-only, the ability to create LZX or XPRESS compressed WIMs, and the
291 correct handling of security descriptors and hard links.
292 * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
293 provides similar capabilities to wimlib-imagex. One thing to note, though,
294 is that it does not support compression and decompression by itself, but
295 instead relies on external native code, such as the codecs from wimlib.
297 A very early version of wimlib is being used to deploy Windows 7 from the
298 Ultimate Deployment Appliance. For more information see
299 http://www.ultimatedeployment.org/.
301 If you are looking for a UNIX archive format that provides features similar to
302 WIM, I recommend you take a look at SquashFS (http://squashfs.sourceforge.net/).
306 As of version 1.0.0, wimlib and all programs and scripts distributed with it are
307 released under the GNU GPL version 3.0 or later.
309 wimlib is independently developed and does not contain any code, data, or files
310 copyrighted by Microsoft. It is not known to be affected by any patents.
312 On UNIX-like systems, if you do not want wimlib to be dynamically linked with
313 libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
314 implementation with built-in code and there will be no difference in
319 wimlib comes with no warranty whatsoever. Please submit a bug report (to
320 ebiggers3@gmail.com) if you find a bug in wimlib and/or wimlib-imagex.
322 Be aware that some parts of the WIM file format are poorly documented or even
323 completely undocumented, so I've just had to do the best I can to read and write
324 WIMs that appear to be compatible with Microsoft's software.
git://wimlib.net / wimlib / blob