3 This is wimlib version 1.13.5 (December 2021). wimlib is a C library for
4 creating, modifying, extracting, and mounting files in the Windows Imaging
5 Format (WIM files). wimlib and its command-line frontend 'wimlib-imagex'
6 provide a free and cross-platform alternative to Microsoft's WIMGAPI, ImageX,
11 To install wimlib and wimlib-imagex on UNIX-like systems, you can compile from
12 source (e.g. './configure && make && sudo make install'). Alternatively, check
13 if a package has already been prepared for your operating system.
15 To install wimlib and wimlib-imagex on Windows, just download and extract the
16 ZIP file containing the latest binaries. See README.WINDOWS for more details.
18 All official wimlib releases are available from https://wimlib.net.
22 A Windows Imaging (WIM) file is an archive designed primarily for archiving
23 Windows filesystems. However, it can be used on other platforms as well, with
24 some limitations. Like some other archive formats such as ZIP, files in WIM
25 archives may be compressed. WIM archives support multiple compression formats,
26 including LZX, XPRESS, and LZMS. All these formats are supported by wimlib.
28 A WIM archive contains one or more "images", each of which is a logically
29 independent directory tree. Each image has a 1-based index and usually a name.
31 WIM archives provide data deduplication at the level of full file contents. In
32 other words, each unique "file contents" is only stored once in the archive,
33 regardless of how many files have that contents across all images.
35 A WIM archive may be either stand-alone or split into multiple parts.
37 An update of the WIM format --- first added by Microsoft for Windows 8 ---
38 supports solid-mode compression. This refers to files being compressed together
39 (e.g. as in a .tar.xz or .7z archive) rather than separately (e.g. as in a .zip
40 archive). This usually produces a much better compression ratio. Solid
41 archives are sometimes called "ESD files" by Microsoft and may have the ".esd"
42 file extension rather than ".wim". They are supported in wimlib since v1.6.0.
46 wimlib itself is a C library, and it provides a documented public API (See:
47 https://wimlib.net/apidoc) for other programs to use. However, it is also
48 distributed with a command-line program called "wimlib-imagex" that uses this
49 library to implement an imaging tool similar to Microsoft's ImageX.
50 wimlib-imagex supports almost all the capabilities of Microsoft's ImageX as well
51 as additional capabilities. wimlib-imagex works on both UNIX-like systems and
52 Windows, although some features differ between the platforms.
54 Run `wimlib-imagex' with no arguments to see an overview of the available
55 commands and their syntax. Note that the commands have both long and short
56 forms, e.g. `wimlib-imagex apply' is equivalent to `wimapply'. For additional
59 * If you have installed wimlib-imagex on a UNIX-like system, you will find
60 further documentation in the man pages; run `man wimlib-imagex' to get
63 * If you have downloaded the Windows binary distribution, you will find the
64 documentation for wimlib-imagex in PDF format in the "doc" directory. Note
65 that although the documentation is written in the style of UNIX manual
66 pages, it does document Windows-specific behavior when relevant.
70 wimlib (and wimlib-imagex) can create XPRESS, LZX, and LZMS compressed WIM
71 archives. wimlib's compression codecs usually outperform and outcompress their
72 closed-source Microsoft equivalents. Multiple compression levels and chunk
73 sizes as well as solid mode compression are supported. Compression is
74 multithreaded by default. Detailed benchmark results and descriptions of the
75 algorithms used can be found at https://wimlib.net/compression.html.
79 WIM images may contain data, such as named data streams and
80 compression/encryption flags, that are best represented on the NTFS filesystem
81 used on Windows. Also, WIM images may contain security descriptors which are
82 specific to Windows and cannot be represented on other operating systems.
83 wimlib handles this NTFS-specific or Windows-specific data in a
84 platform-dependent way:
86 * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
87 Windows-specific data are supported natively.
89 * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
90 Windows-specific data are ordinarily ignored; however, there is also special
91 support for capturing and extracting images directly to/from unmounted NTFS
92 volumes. This was made possible with the help of libntfs-3g from the
95 For both platforms the code for NTFS capture and extraction is complete enough
96 that it is possible to apply an image from the "install.wim" contained in recent
97 Windows installation media (Vista or later) directly to an NTFS filesystem, and
98 then boot Windows from it after preparing the Boot Configuration Data. In
99 addition, a Windows installation can be captured (or backed up) into a WIM file,
100 and then re-applied later.
104 wimlib can also be used to create customized images of Windows PE on either
105 UNIX-like systems or Windows. Windows PE (Preinstallation Environment) is a
106 lightweight version of Windows that runs entirely from memory and can be used to
107 perform maintenance or to install Windows. It is the operating system that runs
108 when you boot from the Windows installation media.
110 A copy of Windows PE can be found on the installation media for Windows (Vista
111 or later) as the file `sources/boot.wim', or in the Windows Automated
112 Installation Kit (WAIK), which is free to download from Microsoft.
114 A shell script `mkwinpeimg' is provided with wimlib on UNIX-like systems to
115 simplify the process of creating and customizing a bootable Windows PE image,
116 sourcing the needed files from the Windows installation media or from the WAIK.
120 This section documents the dependencies of wimlib and the programs distributed
121 with it, when building for a UNIX-like system from source. If you have
122 downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
123 dependencies were already included and this section is irrelevant.
126 This is a commonly used free library to read and write XML documents.
127 Almost all Linux distributions should include this; however, you may
128 need to install the header files, which might be in a package named
129 "libxml2-dev" or similar. For more information see http://xmlsoft.org/.
131 * libfuse (optional but recommended)
132 Unless configured --without-fuse, wimlib requires a non-ancient version
133 of libfuse. Most Linux distributions already include this, but make
134 sure you have the libfuse package installed, and also libfuse-dev if
135 your distribution distributes header files separately. FUSE also
136 requires a kernel module. If the kernel module is available it should
137 automatically be loaded if you try to mount a WIM image. For more
138 information see http://fuse.sourceforge.net/.
140 * libntfs-3g (optional but recommended)
141 Unless configured --without-ntfs-3g, wimlib requires the library and
142 headers for libntfs-3g to be installed. The minimum required version is
143 2011-4-12, but newer versions contain important bug fixes.
145 * OpenSSL / libcrypto (optional)
146 wimlib can use the SHA-1 message digest implementation from libcrypto
147 (usually provided by OpenSSL) instead of compiling in yet another SHA-1
152 * syslinux (optional)
153 * cabextract (optional)
154 The `mkwinpeimg' shell script will look for several other programs
155 depending on what options are given to it. Depending on your Linux
156 distribution, you may already have these programs installed, or they may
157 be in the software repository. Making an ISO filesystem requires
158 `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
159 requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
160 (http://www.syslinux.org). Retrieving files from the Windows Automated
161 Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
165 This section documents the most important options that may be passed to the
166 "configure" script when building from source:
169 If libntfs-3g is not available or is not version 2011-4-12 or later,
170 wimlib can be built without it, in which case it will not be possible to
171 capture or apply WIM images directly from/to NTFS volumes.
173 The default is --with-ntfs-3g when building for any UNIX-like system,
174 and --without-ntfs-3g when building for Windows.
177 The --without-fuse option disables support for mounting WIM images.
178 This removes dependencies on libfuse and librt. The wimmount,
179 wimmountrw, and wimunmount commands will not work.
181 The default is --with-fuse when building for Linux, and --without-fuse
185 Build in functions for SHA-1 rather than using external SHA-1 functions
186 from libcrypto (usually provided by OpenSSL).
188 The default is to use libcrypto if it is found on your system.
192 wimlib works on both UNIX-like systems (Linux, Mac OS X, FreeBSD, etc.) and
193 Windows (XP and later).
195 As much code as possible is shared among all supported platforms, but there
196 necessarily are some differences in what features are supported on each platform
197 and how they are implemented. Most notable is that file tree scanning and
198 extraction are implemented separately for Windows, UNIX, and UNIX (NTFS-3G
199 mode), to ensure a fast and feature-rich implementation of each platform/mode.
201 wimlib is mainly used on x86 and x86_64 CPUs, but it should also work on a
202 number of other GCC-supported 32-bit or 64-bit architectures. It has been
203 tested on the ARM and MIPS architectures.
205 Currently, gcc and clang are the only supported compilers. A few nonstandard
206 extensions are used in the code.
210 The WIM file format is partially specified in a document that can be found in
211 the Microsoft Download Center. However, this document really only provides an
212 overview of the format and is not a formal specification. It also does not
213 cover later extensions of the format, such as solid resources.
215 With regards to the supported compression formats:
217 - Microsoft has official documentation for XPRESS that is of reasonable quality.
218 - Microsoft has official documentation for LZX, but in two different documents,
219 neither of which is completely applicable to its use in the WIM format, and
220 the first of which contains multiple errors.
221 - There does not seem to be any official documentation for LZMS, so my comments
222 and code in src/lzms_decompress.c may in fact be the best documentation
223 available for this particular compression format.
225 The algorithms used by wimlib's compression and decompression codecs are
226 inspired by a variety of sources, including open source projects and computer
229 The code in ntfs-3g_apply.c and ntfs-3g_capture.c uses the NTFS-3G library,
230 which is a library for reading and writing to NTFS filesystems (the filesystem
231 used by recent versions of Windows). See
232 http://www.tuxera.com/community/open-source-ntfs-3g/ for more information.
234 A limited number of other free programs can handle some parts of the WIM
237 * 7-Zip is able to extract and create WIMs (as well as files in many
238 other archive formats). However, wimlib is designed specifically to handle
239 WIM files and provides features previously only available in Microsoft's
240 implementation, such as the ability to mount WIMs read-write as well as
241 read-only, the ability to create compressed WIMs, the correct handling of
242 security descriptors and hard links, support for LZMS compression, and
243 support for solid archives.
244 * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
245 provides some capabilities of wimlib-imagex, with the help of external
248 If you are looking for an archive format that provides features similar to WIM
249 but was designed primarily for UNIX, you may want to consider SquashFS
250 (http://squashfs.sourceforge.net/). However, you may find that wimlib works
251 surprisingly well on UNIX. It will store hard links and symbolic links, and it
252 supports storing standard UNIX file permissions (owners, groups, and modes);
253 special files such as device nodes and FIFOs; and extended attributes.
254 Actually, I use it to back up my own files on Linux!
258 wimlib was originally a project started by Carl Thijssen for use on Linux in the
259 Ultimate Deployment Appliance (http://www.ultimatedeployment.org/). Since then
260 the code has been entirely rewritten and improved (main author: Eric Biggers).
261 Windows support has been available since version 1.3.0 (March 2013). A list of
262 version-to-version changes can be found in the NEWS file.
266 wimlib is free software that comes with NO WARRANTY, to the extent permitted by
267 law. See the COPYING file for more details.
269 Bug reports, suggestions, and other contributions are appreciated and may be
270 posted to https://wimlib.net/forums/.
272 wimlib is independently developed and does not contain any code, data, or files
273 copyrighted by Microsoft. It is not known to be affected by any patents.
275 On UNIX-like systems, if you do not want wimlib to be dynamically linked with
276 libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
277 implementation with built-in code and there will be no difference in
280 Note: copyright years may be listed using range notation, e.g., 2012-2016,
281 indicating that every year in the range, inclusive, is a copyrightable year that
282 would otherwise be listed individually.
git://wimlib.net / wimlib / blob