3 This is wimlib version 1.5.3 (December 2013). 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 two compression formats: LZX and
28 XPRESS *. Both 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.
39 * Note: The Windows 8 WIMGAPI apparently adds a third format, LZMS, but it is
40 not documented and is incompatible with ImageX and Dism. It is unclear if
41 this new format is actually being used for anything.
45 wimlib itself is a C library, and it provides a documented public API (See:
46 http://wimlib.sourceforge.net) for other programs to use. However, it is also
47 distributed with a command-line program called "wimlib-imagex" that uses this
48 library to implement an imaging tool similar to Microsoft's ImageX.
49 wimlib-imagex supports almost all the capabilities of Microsoft's ImageX as well
50 as additional capabilities. wimlib-imagex works on both UNIX-like systems and
51 Windows, although some features differ between the platforms.
53 Run `wimlib-imagex' with no arguments to see an overview of the available
54 commands and their syntax. For additional documentation:
56 * If you have installed wimlib-imagex on a UNIX-like system, you will find
57 further documentation in the man pages; run `man wimlib-imagex' to get
60 * If you have downloaded the Windows binary distribution, you will find the
61 documentation for wimlib-imagex in PDF format in the "doc" directory,
62 ready for viewing with any PDF viewer. Please note that although the PDF
63 files are converted from UNIX-style "man pages", they do document
64 Windows-specific behavior when appropriate.
68 wimlib (and wimlib-imagex) can create XPRESS or LZX compressed WIM archives.
69 The following tables compare the compression ratio and performance for creating
70 a compressed x86_64 Windows PE image. Note: these timings were done on Windows
71 so that the times would be fully comparable; however, wimlib may have even
72 better performance on other operating systems such as Linux. Timings were done
73 with 2 CPUs available, both of which automatically are used by wimlib for both
74 XPRESS and LZX, and also by imagex.exe but apparently only for LZX.
78 XPRESS Compression LZX Compression
79 wimlib-imagex (v1.5.3): 207,444,390 bytes 188,106,091 bytes
80 Microsoft imagex.exe (Windows 7): 209,960,209 bytes 188,224,481 bytes
82 Table 2. Time to create WIM
84 XPRESS Compression LZX Compression
85 wimlib-imagex (v1.5.3): 73 sec 202 sec
86 Microsoft imagex.exe (Windows 7): 90 sec 149 sec
88 The above LZX data are using explicitly specified maximum compression
89 ('--compress=maximum') as of wimlib v1.5.3. If `wimlib-imagex capture' or
90 `wimlib-imagex capture' is instead run with no '--compress' argument, then a
91 faster LZX compressor is used; it will produce results in between those given
92 for XPRESS and LZX above.
94 Note: if the absolute maximum compression ratio is desired, `wimlib-imagex
95 optimize WIMFILE --recompress --compress-slow' on one of the above
96 LZX-compressed WIMs produces a WIM of 187,089,943 bytes in about 400 seconds.
100 WIM images may contain data, such as alternate data streams and
101 compression/encryption flags, that are best represented on the NTFS filesystem
102 used on Windows. Also, WIM images may contain security descriptors which are
103 specific to Windows and cannot be represented on other operating systems.
104 wimlib handles this NTFS-specific or Windows-specific data in a
105 platform-dependent way:
107 * In the Windows version of wimlib and wimlib-imagex, NTFS-specific and
108 Windows-specific data are supported natively.
110 * In the UNIX version of wimlib and wimlib-imagex, NTFS-specific and
111 Windows-specific data are ordinarily ignored; however, there is also special
112 support for capturing and extracting images directly to/from unmounted NTFS
113 volumes. This was made possible with the help of libntfs-3g from the
116 For both platforms the code for NTFS capture and extraction is complete enough
117 that it is possible to apply an image from the "install.wim" contained in recent
118 Windows installation media (Vista, Windows 7, or Windows 8) directly to a NTFS
119 filesystem, and then boot Windows from it after preparing the Boot Configuration
120 Data. In addition, a Windows installation can be captured (or backed up) into a
121 WIM file, and then re-applied later.
125 A major use for wimlib and wimlib-imagex is to create customized images of
126 Windows PE, the Windows Preinstallation Environment, on either UNIX-like systems
127 or Windows without having to rely on Microsoft's software and its restrictions
130 Windows PE is a lightweight version of Windows that can run entirely from memory
131 and can be used to install Windows from local media or a network drive or
132 perform maintenance. It is the operating system that runs when you boot from
133 the Windows installation media.
135 You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
136 Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
137 Windows Automated Installation Kit (WAIK), which is free to download from
138 Microsoft, inside the `WinPE.cab' file, which you can extract natively on
139 Windows, or on UNIX-like systems if you install either the `cabextract' or
142 In addition, Windows installations and recovery partitions frequently contain a
143 WIM containing an image of the Windows Recovery Environment, which is similar to
146 A shell script `mkwinpeimg' is distributed with wimlib on UNIX-like systems to
147 ease the process of creating and customizing a bootable Windows PE image.
151 This section documents the dependencies of wimlib and the programs distributed
152 with it, when building for a UNIX-like system from source. If you have
153 downloaded the Windows binary distribution of wimlib and wimlib-imagex then all
154 dependencies were already included and this section is irrelevant.
157 This is a commonly used free library to read and write XML files. You
158 likely already have it installed as a dependency for some other program.
159 For more information see http://xmlsoft.org/.
161 * libfuse (optional but highly recommended)
162 Unless configured with --without-fuse, wimlib requires a non-ancient
163 version of libfuse to be installed. Most Linux distributions already
164 include this, but make sure you have the libfuse package installed, and
165 also libfuse-dev if your distribution distributes header files
166 separately. FUSE also requires a kernel module. If the kernel module
167 is available it will automatically be loaded if you try to mount a WIM
168 file. For more information see http://fuse.sourceforge.net/. FUSE is
169 also available for FreeBSD.
171 * libntfs-3g (optional but highly recommended)
172 Unless configured with --without-ntfs-3g, wimlib requires the library
173 and headers for libntfs-3g version 2011-4-12 or later to be installed.
174 Versions dated 2010-3-6 and earlier do not work because they are missing
175 the header xattrs.h (and the file xattrs.c, which contains functions we
176 need). libntfs-3g version 2013-1-13 is compatible only with wimlib
179 * OpenSSL / libcrypto (optional)
180 wimlib can use the SHA1 message digest code from OpenSSL instead of
181 compiling in yet another SHA1 implementation. (See LICENSE section.)
185 * syslinux (optional)
186 * cabextract (optional)
187 The `mkwinpeimg' shell script will look for several other programs
188 depending on what options are given to it. Depending on your Linux
189 distribution, you may already have these programs installed, or they may
190 be in the software repository. Making an ISO filesystem requires
191 `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
192 requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
193 (http://www.syslinux.org). Retrieving files from the Windows Automated
194 Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
198 This section documents the most important options that may be passed to the
199 "configure" script when building from source:
202 If libntfs-3g is not available or is not version 2011-4-12 or later,
203 wimlib can be built without it, in which case it will not be possible to
204 apply or capture images directly to/from NTFS volumes.
207 If libfuse or the FUSE kernel module is not available, wimlib can be
208 compiled with --without-fuse. This will remove the ability to mount and
212 Build in functions for SHA1 rather than using external SHA1 functions
213 from libcrypto (part of OpenSSL). The default is to use libcrypto if it
214 is found on the system.
216 --enable-xattr, --disable-xattr
217 Enable or disable support for the extended-attributes interface to NTFS
218 alternate data streams in mounted WIMs. To support these, wimlib
219 requires that the setxattr() function and the attr/xattr.h header are
220 available. The default is to autodetect whether support is possible.
222 --disable-multithreaded-compression
223 By default, data will be compressed using multiple threads when writing
224 a WIM, unless only 1 processor is detected. Specify this option to
225 disable support for this.
228 Use a very fast assembly language implementation of SHA1 from Intel.
229 Only use this if the build target supports the SSSE3 instructions.
231 --disable-error-messages
232 Save some space by removing all error messages from the library.
235 Remove assertions included by default.
239 wimlib has primarily been tested on Linux and Windows (primarily Windows 7, but
240 also Windows XP and Windows 8).
242 wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
243 you do not have libntfs-3g 2011-4-12 or later available, you must configure
244 wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
245 load the POSIX message queue module (run `kldload mqueuefs').
247 The code has primarily been tested on x86 and x86_64 CPUs, but it's written to
248 be portable to other architectures and I've also tested it on ARM. However,
249 although the code is written to correctly deal with endianness, it has not yet
250 actually been tested on a big-endian architecture.
254 The WIM file format is specified in a document that can be found in the
255 Microsoft Download Center. There is a similar document that specifies the LZX
256 compression format, and a document that specifies the XPRESS compression format.
257 However, many parts of these formats are poorly documented, and some parts have
258 no documentation whatsoever. Some particularly poorly documented parts of the
259 formats have had comments added in various places in the library code. Please
260 see the code and/or ask me if you have any questions about the WIM file format
261 as it exists in reality and not as it exists in Microsoft's poorly written
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 lzx-decompress.c, the code to decompress WIM file resources that are compressed
270 using LZX compression, was originally based on code from the cabextract project
271 (http://www.cabextract.org.uk) but has been rewritten.
273 lzx-compress.c, the code to compress WIM file resources using LZX compression,
274 was originally based on code written by Matthew Russotto (www.russotto.net/chm/)
275 but has been rewritten.
277 lz77.c, the code to find LZ77 matches (used for both XPRESS and LZX
278 compression), is based on code from zlib but has been rewritten.
280 A limited number of other free programs can handle some parts of the WIM
283 * 7-zip is able to extract and create WIMs (as well as files in many
284 other archive formats). However, wimlib is designed specifically to handle
285 WIM files and provides features previously only available in Microsoft's
286 imagex.exe, such as the ability to mount WIMs read-write as well as
287 read-only, the ability to create LZX or XPRESS compressed WIMs, and the
288 correct handling of security descriptors and hard links.
289 * ImagePyX (https://github.com/maxpat78/ImagePyX) is a Python program that
290 provides similar capabilities to wimlib-imagex. One thing to note, though,
291 is that it does not support compression and decompression by itself, but
292 instead relies on external native code, such as the codecs from wimlib.
294 A very early version of wimlib is being used to deploy Windows 7 from the
295 Ultimate Deployment Appliance. For more information see
296 http://www.ultimatedeployment.org/.
298 You can see the documentation about Microsoft's version of ImageX at
299 http://technet.microsoft.com/en-us/library/cc749447(v=ws.10).aspx, so you can
300 see how it compares to wimlib-imagex.
302 If you are looking for a UNIX archive format that provides features similar to
303 WIM, I recommend you take a look at SquashFS (http://squashfs.sourceforge.net/).
307 As of version 1.0.0, wimlib and all programs and scripts distributed with it are
308 released under the GNU GPL version 3.0 or later.
310 wimlib is independently developed and does not contain any code, data, or files
311 copyrighted by Microsoft. It is not known to be affected by any patents.
313 On UNIX-like systems, if you do not want wimlib to be dynamically linked with
314 libcrypto (OpenSSL), configure with --without-libcrypto. This replaces the SHA1
315 implementation with built-in code and there will be no difference in
320 wimlib comes with no warranty whatsoever. Use Microsoft's `imagex.exe' if you
321 want to make sure your WIM files are made "correctly" (but beware: Microsoft's
322 version contains some bugs).
324 Please submit a bug report (to ebiggers3@gmail.com) if you find a bug in wimlib
325 and/or wimlib-imagex.
327 Be aware that some parts of the WIM file format are poorly documented or even
328 completely undocumented, so I've just had to do the best I can to read and write
329 WIMs that appear to be compatible with Microsoft's software.
git://wimlib.net / wimlib / blob