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. wimlib includes its own compression codecs and does not use the
66 compression API available on some versions of Windows. The below table provides
67 the results (file size, in bytes, and time to create, in seconds) of capturing a
68 WIM containing a x86 Windows PE image, using various compression types and
69 options. When applicable, the results with the equivalent Microsoft
70 implementation in WIMGAPI, which is the library used by ImageX and Dism, are
73 ===========================================================================
74 | Compression type || wimlib (v1.6.1) | WIMGAPI (Windows 8) |
75 ===========================================================================
76 | None [1] || 531,979,435 in 18s | 531,980,333 in 24s |
77 | XPRESS [2] || 207,369,912 in 22s | 209,886,010 in 39s |
78 | LZX (quick) [3] || 194,876,901 in 29s | N/A |
79 | LZX (normal) [4] || 187,962,713 in 158s | 188,163,523 in 125s |
80 | LZX (slow) [5] || 186,913,423 in 358s | N/A |
81 | LZMS (non-solid) [6] || 176,880,594 in 182s | N/A |
82 | LZMS (solid) [7] || 136,507,304 in 494s | 126,735,608 in 623s |
83 ===========================================================================
86 [1] '--compress=none' for wimlib-imagex;
87 '/compress none' or no option for ImageX.
89 [2] '--compress=fast' or '--compress=XPRESS' for wimlib-imagex;
90 '/compress fast' or no option for ImageX.
91 Compression chunk size is 32768 (the default for XPRESS).
93 [3] No compression option specified to wimlib-imagex; no known equivalent for
94 WIMGAPI (ImageX uses XPRESS compression if no option specified).
95 Compression chunk size is 32768 (the default for LZX).
97 [4] '--compress=maximum' or '--compress=LZX' for wimlib-imagex;
98 '/compress maximum' for ImageX.
99 Compression chunk size is 32768 (the default for LZX).
101 [5] '--compress=maximum --compress-slow' for wimlib-imagex;
102 no known equivalent for WIMGAPI.
103 Compression chunk size is 32768 (the default for LZX).
105 [6] '--compress=recovery' or '--compress=LZMS' for wimlib-imagex;
106 no known way to create the equivalent with WIMGAPI.
107 Compression chunk size is 131072 (the default for LZMS). Note: this
108 compression type is not generally recommended due to its limited
109 compatibility with the MS implementations.
111 [7] '--compress=recovery --packed-streams' or
112 '--compress=LZMS --packed-streams' for wimlib-imagex;
113 WIMCreateFile with WIM_COMPRESSION_LZMS and flag 0x20000000 for WIMGAPI.
114 Compression chunk size in packed resources is 33554432 for wimlib,
115 67108864 for WIMGAPI. Note: this compression type is not generally
116 recommended due to its limited compatibility with the MS implementations.
117 Also, due to the large chunk size, wimlib uses about 500MB of memory per
118 thread when compressing in this format.
120 The above timings were done on Windows 8 (x86) so that side-by-side comparisons
121 with the Microsoft implementation would be possible; however, wimlib may have
122 even better performance on other operating systems such as Linux. The system
123 had 2 CPUs and 2 GiB of memory available. All times were done with the page
124 cache warmed, so the times primarily measure the performance of the compression
125 algorithms and not the time to read data from disk, which presumably is similar
126 in each implementation.
128 Below are results for compressing the Canterbury corpus using wimlib (v1.6.1),
129 WIMGAPI (Windows 8), and some other formats/programs, including the archive size
130 only. Note that the Canterbury corpus includes no duplicate files or hard
131 links, which WIM handles better than most other formats by storing only distinct
134 =================================================
135 | Format | Size (bytes) |
136 =================================================
138 | WIM (WIMGAPI, None) | 2,814,278 |
139 | WIM (wimlib, None) | 2,813,856 |
140 | WIM (WIMGAPI, XPRESS) | 825,410 |
141 | WIM (wimlib, XPRESS) | 792,024 |
142 | tar.gz (gzip, default) | 738,796 |
143 | ZIP (Info-ZIP, default) | 735,334 |
144 | tar.gz (gzip, -9) | 733,971 |
145 | ZIP (Info-ZIP, -9) | 732,297 |
146 | WIM (wimlib, LZX quick) | 722,196 |
147 | WIM (WIMGAPI, LZX) | 651,766 |
148 | WIM (wimlib, LZX normal) | 639,464 |
149 | WIM (wimlib, LZX slow) | 633,144 |
150 | WIM (wimlib, LZMS non-solid) | 590,252 |
151 | tar.bz2 (bzip, default) | 565,008 |
152 | tar.bz2 (bzip, -9) | 565,008 |
153 | WIM (wimlib, LZMS solid) | 534,218 |
154 | WIM (wimlib, LZMS solid, slow) | 529,904 |
155 | WIM (WIMGAPI, LZMS solid) | 521,232 |
156 | tar.xz (xz, default) | 486,916 |
157 | tar.xz (xz, -9) | 486,904 |
158 | 7z (7-zip, default) | 484,700 |
159 | 7z (7-zip, -9) | 483,239 |
160 =================================================
164 WIM images may contain data, such as alternate data streams and
165 compression/encryption flags, that are best represented on the NTFS filesystem
166 used on Windows. Also, WIM images may contain security descriptors which are
167 specific to Windows and cannot be represented on other operating systems.
168 wimlib handles this NTFS-specific or Windows-specific data in a
169 platform-dependent way:
171 * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
172 Windows-specific data are supported natively.
174 * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
175 Windows-specific data are ordinarily ignored; however, there is also special
176 support for capturing and extracting images directly to/from unmounted NTFS
177 volumes. This was made possible with the help of libntfs-3g from the
180 For both platforms the code for NTFS capture and extraction is complete enough
181 that it is possible to apply an image from the "install.wim" contained in recent
182 Windows installation media (Vista, Windows 7, or Windows 8) directly to a NTFS
183 filesystem, and then boot Windows from it after preparing the Boot Configuration
184 Data. In addition, a Windows installation can be captured (or backed up) into a
185 WIM file, and then re-applied later.
189 A major use for wimlib and wimlib-imagex is to create customized images of
190 Windows PE, the Windows Preinstallation Environment, on either UNIX-like systems
191 or Windows without having to rely on Microsoft's software and its restrictions
194 Windows PE is a lightweight version of Windows that can run entirely from memory
195 and can be used to install Windows from local media or a network drive or
196 perform maintenance. It is the operating system that runs when you boot from
197 the Windows installation media.
199 You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
200 Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
201 Windows Automated Installation Kit (WAIK), which is free to download from
202 Microsoft, inside the `WinPE.cab' file, which you can extract natively on
203 Windows, or on UNIX-like systems if you install either the `cabextract' or
206 In addition, Windows installations and recovery partitions frequently contain a
207 WIM containing an image of the Windows Recovery Environment, which is similar to
210 A shell script `mkwinpeimg' is distributed with wimlib on UNIX-like systems to
211 ease the process of creating and customizing a bootable Windows PE image.
215 This section documents the dependencies of wimlib and the programs distributed
216 with it, when building for a UNIX-like system from source. If you have
217 downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
218 dependencies were already included and this section is irrelevant.
221 This is a commonly used free library to read and write XML files. You
222 likely already have it installed as a dependency for some other program.
223 For more information see http://xmlsoft.org/.
225 * libfuse (optional but highly recommended)
226 Unless configured with --without-fuse, wimlib requires a non-ancient
227 version of libfuse to be installed. Most Linux distributions already
228 include this, but make sure you have the libfuse package installed, and
229 also libfuse-dev if your distribution distributes header files
230 separately. FUSE also requires a kernel module. If the kernel module
231 is available it will automatically be loaded if you try to mount a WIM
232 file. For more information see http://fuse.sourceforge.net/. FUSE is
233 also available for FreeBSD.
235 * libntfs-3g (optional but highly recommended)
236 Unless configured with --without-ntfs-3g, wimlib requires the library
237 and headers for libntfs-3g version 2011-4-12 or later to be installed.
238 Versions dated 2010-3-6 and earlier do not work because they are missing
239 the header xattrs.h (and the file xattrs.c, which contains functions we
240 need). libntfs-3g version 2013-1-13 is compatible only with wimlib
243 * OpenSSL / libcrypto (optional)
244 wimlib can use the SHA1 message digest code from OpenSSL instead of
245 compiling in yet another SHA1 implementation. (See LICENSE section.)
249 * syslinux (optional)
250 * cabextract (optional)
251 The `mkwinpeimg' shell script will look for several other programs
252 depending on what options are given to it. Depending on your Linux
253 distribution, you may already have these programs installed, or they may
254 be in the software repository. Making an ISO filesystem requires
255 `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
256 requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
257 (http://www.syslinux.org). Retrieving files from the Windows Automated
258 Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
262 This section documents the most important options that may be passed to the
263 "configure" script when building from source:
266 If libntfs-3g is not available or is not version 2011-4-12 or later,
267 wimlib can be built without it, in which case it will not be possible to
268 apply or capture images directly to/from NTFS volumes.
271 If libfuse or the FUSE kernel module is not available, wimlib can be
272 compiled with --without-fuse. This will remove the ability to mount and
276 Build in functions for SHA1 rather than using external SHA1 functions
277 from libcrypto (part of OpenSSL). The default is to use libcrypto if it
278 is found on the system.
280 --enable-xattr, --disable-xattr
281 Enable or disable support for the extended-attributes interface to NTFS
282 alternate data streams in mounted WIMs. To support these, wimlib
283 requires that the setxattr() function and the attr/xattr.h header are
284 available. The default is to autodetect whether support is possible.
286 --disable-multithreaded-compression
287 By default, data will be compressed using multiple threads when writing
288 a WIM, unless only 1 processor is detected. Specify this option to
289 disable support for this.
292 Use a very fast assembly language implementation of SHA1 from Intel.
293 Only use this if the build target supports the SSSE3 instructions.
295 --disable-error-messages
296 Save some space by removing all error messages from the library.
299 Remove assertions included by default.
303 wimlib has primarily been tested on Linux and Windows (primarily Windows 7, but
304 also Windows XP and Windows 8).
306 wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
307 you do not have libntfs-3g 2011-4-12 or later available, you must configure
308 wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
309 load the POSIX message queue module (run `kldload mqueuefs').
311 The code has primarily been tested on x86 and x86_64 CPUs, but it's written to
312 be portable to other architectures and I've also tested it on ARM. However,
313 although the code is written to correctly deal with endianness, it has not yet
314 actually been tested on a big-endian architecture.
318 The WIM file format is partially specified in a document that can be found in
319 the Microsoft Download Center. However, this document really only provides an
320 overview of the format and is not a formal specification.
322 With regards to the supported compression formats:
324 - Microsoft has official documentation for XPRESS that is of reasonable quality.
325 - Microsoft has official documentation for LZX but it contains errors.
326 - There does not seem to be any official documentation for LZMS, so my comments
327 and code in src/lzms-decompress.c may in fact be the best documentation
328 available for this particular compression format.
330 The code in ntfs-3g_apply.c and ntfs-3g_capture.c uses the NTFS-3g library,
331 which is a library for reading and writing to NTFS filesystems (the filesystem
332 used by recent versions of Windows). See
333 http://www.tuxera.com/community/ntfs-3g-download/ for more information.
335 The LZX decompressor (lzx-decompress.c) was originally based on code from the
336 cabextract project (http://www.cabextract.org.uk) but has been rewritten.
338 The LZX compressor (lzx-compress.c) was originally based on code written by
339 Matthew Russotto (www.russotto.net/chm/) but has been rewritten. It now uses
340 suffix array construction code from divsufsort
341 (https://code.google.com/p/libdivsufsort/) and algorithms from 7-Zip as well as
342 several published papers.
344 lz_hash.c contains a hash-table-based LZ77 matchfinder that is based on code
345 from zlib but has been rewritten. This code is applicable to XPRESS, LZX, and
346 LZMS, all of which are partly based on LZ77 compression.
348 A limited number of other free programs can handle some parts of the WIM
351 * 7-zip is able to extract and create WIMs (as well as files in many
352 other archive formats). However, wimlib is designed specifically to handle
353 WIM files and provides features previously only available in Microsoft's
354 implementation, such as the ability to mount WIMs read-write as well as
355 read-only, the ability to create LZX or XPRESS compressed WIMs, and the
356 correct handling of security descriptors and hard links.
357 * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
358 provides similar capabilities to wimlib-imagex. One thing to note, though,
359 is that it does not support compression and decompression by itself, but
360 instead relies on external native code, such as the codecs from wimlib.
362 A very early version of wimlib is being used to deploy Windows 7 from the
363 Ultimate Deployment Appliance. For more information see
364 http://www.ultimatedeployment.org/.
366 If you are looking for a UNIX archive format that provides features similar to
367 WIM, I recommend you take a look at SquashFS (http://squashfs.sourceforge.net/).
371 As of version 1.0.0, wimlib and all programs and scripts distributed with it are
372 released under the GNU GPL version 3.0 or later.
374 wimlib is independently developed and does not contain any code, data, or files
375 copyrighted by Microsoft. It is not known to be affected by any patents.
377 On UNIX-like systems, if you do not want wimlib to be dynamically linked with
378 libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
379 implementation with built-in code and there will be no difference in
384 wimlib comes with no warranty whatsoever. Please submit a bug report (to
385 ebiggers3@gmail.com) if you find a bug in wimlib and/or wimlib-imagex.
387 Be aware that some parts of the WIM file format are poorly documented or even
388 completely undocumented, so I've just had to do the best I can to read and write
389 WIMs that appear to be compatible with Microsoft's software.
git://wimlib.net / wimlib / blob